Article

A comparison of conventional versus locking plates in intraarticular calcaneus fractures: A biomechanical study in human cadavers

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Abstract

Internal fixation of displaced intraarticular calcaneal fractures in patients older than 50 years remains controversial. This is, in many cases, due to fear of loss of fixation and the risk of implant failure in osteoporotic bone. It is the objective of this study to compare the fixation strength obtained using calcaneal plates with and without locking screws, in the fixation of osteoporotic cadaveric intraarticular calcaneal fractures. In seven pairs of fresh frozen lower limbs cadavers, intraarticular calcaneal fractures were created with a dynamic single impact loading device and stabilized using either the low profile locking plate, or the conventional calcaneus plate. Radiographs were obtained to assess reduction. The specimens were then subjected to cyclic loading followed by loading to failure, using matched pairs of cadaveric lower limbs. The Wilcoxon signed rank test was used to test for differences in the results. The locking plate showed a significant lower irreversible deformation during cyclic loading and a significant higher load to failure. The difference between the ultimate displacement, and work to failure was not significant. A low bone mineral content in the area of the posterior facet correlated only in the conventional plate group with increased irreversible deformation. This study supports the mechanical viability of using locking calcaneal plates for the fixation of intraarticular calcaneal fractures in elderly patients.

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... Another valuable finding in the current study is related to the order of observed failure pattern appearance. While some biomechanical human cadaveric studies have reported initial failure at the posterior facet fracture line, the failure pattern observed in the present study had a different sequence [27] . The specimens in all groups failed first at the Gissane angle, followed by the anterior articular surface and finally by plantar gapping. ...
... Although the mechanical superiority of locking plates to non-locking ones in DIACF osteosynthesis is still debated, locked plating has proven to be noninferior [26] . Locking plates are the implant of choice in osteoporotic bone [27] . With the introduction of VA locking, calcaneal plates have solved a major problem -fixed screw orientation being not flexible to variations in fracture pattern or anatomy. ...
... It has been demonstrated that cyclic loading reveals additional differences in the biomechanical characteristics of tested implants that quasi-static testing to failure alone does not [37] . All specimens survived a load higher than the average force of 755 N at heel strike suggested in the literature [27] . The loading protocol was characterized by the link between the cycle number and the applied load. ...
Article
Treatment of comminuted intraarticular calcaneal fractures remains controversial and challenging. The aim of this study was to investigate the biomechanical performance of three different methods for fixation of such fractures. Comminuted calcaneal fractures, including Sanders III AB fracture of the posterior facet and Kinner II B fracture of the calcaneocuboid joint (CCJ) articular calcaneal surface, were created in 18 human cadaveric lower legs by osteotomizing. The ankle joint, medial soft tissues and midtarsal bones along with their ligaments were preserved. The specimens were randomized to three groups for fixation with either (1) 2.7 mm variable-angle locking lateral calcaneal plate (Group 1), (2) 2.7 mm variable-angle locking anterolateral calcaneal plate in combination with one 4.5 mm and one 6.5 mm cannulated screws (Group 2), or (3) interlocking calcaneal nail with 3.5 mm screws in combination with three separate 4.0 mm cannulated screws (Group 3). All specimens were biomechanically tested to failure under axial loading in midstance foot position. Each test commenced with a quasi-static compression ramp from 50 to 200 N, followed by progressively increasing cyclic loading at 2 Hz. Starting from 200 N, the peak load of each cycle increased at a rate of 0.2 N/cycle. Interfragmentary movements were captured by optical motion tracking. In addition, mediolateral X-rays were taken every 250 cycles with a triggered C-arm. Böhler angle after 5000 cycles (1200 N peak load) increased significantly more in Group 1 compared to both other groups (P ≤ 0.020). Varus deformation of 10° between the calcaneal tuberosity and the lateral calcaneal fragments was reached at significantly lower number of cycles in Group 1 compared the other groups (P ≤ 0.017). Both cycles to 10° plantar gapping between the anterior process and the calcaneal tuberosity fragments, and 2 mm displacement at the CCJ articular calcaneal surface revealed no significant differences among the groups (P ≥ 0.773). From a biomechanical perspective, treatment of comminuted intraarticular calcaneal fractures using anterolateral variable-angle locking plate with additional longitudinal screws or interlocked nail in combination with separate transversal screws provides superior stability as opposed to lateral variable-angle locked plating only.
... The investigated calcaneal fracture fixation techniques included conventional plates, locking plates, unicortical screws, bicortical screws, small fragment plates, intramedullary devices, augmented screw osteosynthesis, compression bolts, and longitudinal screws added to lateral plates. The results of the included studies are listed in the Table (3,8,10,(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). The authors concluded that all tested fixation methods seemed to be biomechanically adequate and did not differ significantly from each other. ...
... The authors concluded that all tested fixation methods seemed to be biomechanically adequate and did not differ significantly from each other. The use of locking devices did not seem to strengthen the construction compared with the conventional devices (10,(20)(21)(22). ...
... It is well known that artificial bones have different biomechanical characteristics than human bone (34), mandating careful interpretation of their results. Four studies biomechanically investigated locking plates (10,(20)(21)(22). Three studies failed to show a significant beneficial effect of locking plates compared with nonlocking plates in the fixation of calcaneal fractures, questioning the benefit of using locking plates in these patients (10,20,21). ...
Article
Calcaneal fractures are notoriously difficult to treat and wound complications occur often. However, owing to the rare nature of these fractures, clinical trials on this subject are lacking. Thus, biomechanical studies form a viable source of information on this subject. With our systematic review of biomechanical studies, we aimed to provide an overview of all the techniques available and guide clinicians in their choice of method of fracture fixation. A literature search was conducted using 3 online databases to find biomechanical studies investigating methods of fixation for calcaneal fractures. A total of 14 studies investigating 237 specimens were identified. Large diversity was found in the tested fixation methods and in the test setups used. None of the studies found a significant difference in favor of any of the fixation methods. All tested methods provided a biomechanically stable fixation. All the investigated methods of fixation for calcaneal fractures seem to be biomechanically sufficient. No clear benefit was found for locking plates in the fixation of calcaneal fractures; however, a subtle mechanical superiority might exist compared with nonlocking plates in the case of fractures in osteoporotic bone. Several of the techniques tested would be suitable for a minimal invasive approach. These should be investigated further in clinical trials.
... There have been several studies on the biomechanics of locking/nonlocking plates and comparisons between plate and screw fixations (Redfern et al., 2006;Smerek et al., 2008;Stoffel et al., 2007;Wang et al., 1998), but few reports on the comparison of all these modalities. Finite-element (FE) analysis is a powerful tool for handling clinical biomechanical problems (Huang et al., 2013;Liang et al., 2011;Niu et al., 2014;Ren et al., 2015;Wong et al., 2015). ...
... We used a cadaveric experiment to develop and validate a computational model of a Sanders type III fracture, a common type of fracture, the biomechanics of which have been frequently studied (Ni et al., 2015;Smerek et al., 2008;Stoffel et al., 2007;Wang et al., 1998). In this study, we simulated the stance phase of a walking gait, a typical and mechanically demanding loading pattern. ...
Article
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The locking plate and percutaneous crossing metallic screws and crossing absorbable screws have been used clinically to treat intra-articular calcaneal fractures, but little is known about the biomechanical differences between them. This study compared the biomechanical stability of calcaneal fractures fixed using a locking plate and crossing screws. Three-dimensional finite-element models of intact and fractured calcanei were developed based on the CT images of a cadaveric sample. Surgeries were simulated on models of Sanders type III calcaneal fractures to produce accurate postoperative models fixed by the three implants. A vertical force was applied to the superior surface of the subtalar joint to simulate the stance phase of a walking gait. This model was validated by an in vitro experiment using the same calcaneal sample. The intact calcaneus showed greater stiffness than the fixation models. Of the three fixations, the locking plate produced the greatest stiffness and the highest von Mises stress peak. The micromotion of the fracture fixated with the locking plate was similar to that of the fracture fixated with the metallic screws but smaller than that fixated with the absorbable screws. Fixation with both plate and crossing screws can be used to treat intra-articular calcaneal fractures. In general, fixation with crossing metallic screws is preferable because it provides sufficient stability with less stress shielding.
... Recent studies have demonstrated that locking plate constructs can be as stiff as the conventional plating constructs [4,5] designed to induce direct bone healing. The relatively high stiffness of locked bridge plating constructs may therefore suppress IFM to an insufficient level, resulting in complications in healing, including delayed union, nonunion, and implant failure [6][7][8] . ...
... Ahmad et al. [23] reported that the construct strength was influenced by increasing the distance between the plate and the bone. However, the results obtained in this study (approximately 3700-6100 N) were all higher than the locked plates (2600 N) tested in human femora under similar loading conditions [5] irrespective of the distance of the plate from the bone. During these experiments, fixation failure was noted for the plate at both 2 mm and 4 mm. ...
Article
Full-text available
The far cortical locking (FCL) system, a novel bridge-plating technique, aims to deliver controlled and symmetric interfragmentary motion for a potential uniform callus distribution. However, clinical data for the practical use of this system are limited. The current study investigated the biomechanical effect of a locking plate/far cortical locking construct on a simulated comminuted diaphyseal fracture of the synthetic bones at different distance between the plate and the bone. Biomechanical in vitro experiments were performed using composite sawbones as bone models. A 10-mm osteotomy gap was created and bridged with FCL constructs to determine the construct stiffness, strength, and interfragmentary movement under axial compression, which comprised one of three methods: locking plates applied flush to bone, at 2 mm, or at 4 mm from the bone. The plate applied flush to the bone exhibited higher stiffness than those at 2 mm and 4 mm plate elevation. A homogeneous interfragmentary motion at the near and far cortices was observed for the plate at 2 mm, whereas a relatively large movement was observed at the far cortex for the plate applied at 4 mm. A plate-to-bone distance of 2 mm had the advantages of reducing axial stiffness and providing nearly parallel interfragmentary motion. The plate flush to the bone prohibits the dynamic function of the far cortical locking mechanism, and the 4-mm offset was too unstable for fracture healing.
... Axial compression was applied through a spherical bearing proximally while the distal end of the specimen was rigidly mounted to the load cell for consistency with prior studies ( Figure 3A). 27,31,32 Torsion was applied around the diaphyseal shaft axis ( Figure 3B). Bending was applied in a four-point-bending setup to generate a constant bending moment over the entire plate length ( Figure 3C). ...
... This failure mode is consistent with prior studies in which locked plating constructs failed in torsion as a result of screw breakage. 27,32 In osteoporotic specimens, dynamic constructs also exhibited a 25% greater bending strength than LP constructs. Both constructs failed by transverse fracture at the plate end. ...
Article
Axial dynamization of an osteosynthesis construct can promote fracture healing. This biomechanical study evaluated a novel dynamic locking plate that derives symmetric axial dynamization by elastic suspension of locking holes within the plate. Standard locked and dynamic plating constructs were tested in a diaphyseal bridge-plating model of the femoral diaphysis to determine the amount and symmetry of interfragmentary motion under axial loading, and to assess construct stiffness under axial loading, torsion, and bending. Subsequently, constructs were loaded until failure to determine construct strength and failure modes. Finally, strength tests were repeated in osteoporotic bone surrogates. One body-weight axial loading of standard locked constructs produced asymmetric interfragmentary motion that was over three times smaller at the near cortex (0.1 ± 0.01 mm) than at the far cortex (0.32 ± 0.02 mm). Compared to standard locked constructs, dynamic plating constructs enhanced motion by 0.32 mm at the near cortex and by 0.33 mm at the far cortex and yielded a 77% lower axial stiffness (p < 0.001). Dynamic plating constructs were at least as strong as standard locked constructs under all test conditions. In conclusion, dynamic locking plates symmetrically enhance interfragmentary motion, deliver controlled axial dynamization, and are at least comparable in strength to standard locked constructs. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
... However, the biomechanical experiment by Richter et al 23 confirmed that the locking plate provided a better stability than the non-locking plate did in calcaneal fractures. Stoffel et al 24 thought that the locking plate had the mechanical advantages of improved fixation strength and better load-bearing in elderly patients with calcaneal intraarticular fractures. Illert et al 22 We found some differences between the two experiments. ...
Article
Full-text available
Purpose To evaluate the clinical outcomes of locking calcaneal plate in treating calcaneal fracture (Sanders II–III) in elderly patients. Methods From October 2012 to December 2013, 23 elderly patients suffering from calcaneal fracture (Sanders II–III) were treated and followed up. There were 15 males and 8 females with the mean age of 68.5 years (range: 65–79 years). According to Sander's classification, 16 cases (16 feet) were type II fractures and 7 cases (7 feet) were type III fractures. Anteroposterior, lateral and axial views of X-ray were taken to detect the calcaneum. CT scan was done to assess the amount of comminution and articular depression. Radiological assessment was performed using Bohler's angle and Gissane's angle. Functional outcome was assessed using the Maryland foot score. Results All the patients were followed up for 13.7 months on average (10–20 months). The mean time of bone union was 3.2 months (3–4 months). The mean time of complete weight bearing was 3.2 months (3.1–4.0 months). The soft tissue necrosis was found in 1 case. The mean Bohler's angle and Gissane's angle were 25.31° and 117.5° respectively. The overall excellent to good rate was 82.6%. Conclusion Open reduction and internal fixation with locking calcaneal plate can obtain good functional outcome for Sanders II–III calcaneal fractures in elderly patients.
... The advent of modern locking plates has allowed improved fixation of the peri-articular fractures. Numerous studies have demonstrated and confirmed the increased stability provided by locking plates at the distal femur, proximal tibia, calcaneum, distal radius and proximal humerus [21][22][23][24][25]. This increased strength of fixation has in some cases obviated the need for dual column fixation. ...
Article
Full-text available
Management of extra-articular distal humerus fractures presents a challenge to the treating surgeon due to the complex anatomy of the distal part of the humerus and complicated fracture morphology. Although surgical treatment has shown to provide a more stable reduction and alignment and predictable return to function, it has been associated with complications like iatrogenic radial nerve palsy, infection, non-union and Implant failure. We in the present series retrospectively analysed 20 patients with extra-articular distal humerus shaft fractures surgically treated using the extra-articular distal humeral locking plate approached by the triceps-sparing posterolateral approach. The outcome was assessed using the DASH score, range of motion at the elbow and the time to union. The mean time to radiographic fracture union was 12 weeks.
... Failure was defined by reaching the maximum load of 5000 N or a 0-degree gradient in the load deformation diagram. 19 The load deformation data of the hydraulic testing device were registered via MTS FlexTest 40 multipurpose testware software. Interfragmentary movement was detected by 2 charge-coupled device cameras connected to a computer. ...
... Although the advantages of locking plates on calcaneus fractures are controversial, many studies proved the superiority of locking plates over conventional constructions. [7,8] In this study, we aimed to evaluate the possible effects of early weight-bearing on clinical and radiological outcomes of comminuted calcaneal fractures treated with locking plates. ...
... Redfern et al. (38) and Stoffel et al. (39) used models of intraarticular fractures in parts of cadavers to compare fixation using locking or non-locking plates in biomechanical studies testing strength, deformity, and workload. Redfern et al. (38) , in experimental models with Sanders type IIB fractures, found no advantages between the fixation with locking plates or the traditional fixation with non-locking plates. ...
Article
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Objective: Verify the variables of plantar pressure distribution of patients submitted to surgical procedure for calcaneal fracture, and correlate them with two different surgical approaches. Method: The authors studied 15 patients between 20 and 53 years of age (average 40.06 yrs.) who had intra-joint calcaneal fractures, submitted to surgical treatment by means of two different approaches: the lateral and the sinus tarsi. The authors checked the plantar pressure distribution by correlating these variables with the two different surgical approaches. The plantar pressure distribution was assessed using the Pedar System (Novel, Gmbh, Munich, Germany), by checking the maximum peak of the hindfoot and forefoot pressure on the affected and the normal sides. Results: the mean maximum pressure of the hindfoot plantigram in both approaches showed no statistical difference (t=0.11; p=0.91), as well as the mean maximum pressure of the forefoot plantigram (t=-0,48; p=0,64). Conclusion: The authors have concluded that there were no significant statistical differences between the average maximum peak of the hindfoot and forefoot pressure on the affected side as compared to the normal side, and these variables have showed no differences when compared to the surgical approach used.
... [9] Carr et al for more severe deformity (Stephens type III), the subtalar joint can undergo arthrodesis with corrective calcaneal osteotomy. [11]The goal of these measures is correction of the deformity and relief of the pain by osteotomy and subtalar arthrodesis. However ,there were few reports about restoring subtalar congruency with reconstructive osteotomy when treating calcaneal malunions. ...
... Although the advantages of locking plates on calcaneus fractures are controversial, many studies proved the superiority of locking plates over conventional constructions. [7,8] In this study, we aimed to evaluate the possible effects of early weight-bearing on clinical and radiological outcomes of comminuted calcaneal fractures treated with locking plates. ...
Article
Objectives: This study aims to evaluate the possible effects of early weight-bearing on clinical and radiological outcomes of comminuted calcaneal fractures treated with locking plates. Patients and methods: This retrospective study included 15 patients (12 males, 3 females; mean age 40.1 years; range 18 to 55 years) with comminuted calcaneal fractures between October 2010 and April 2012. Standard lateral extensile approach was carried out for surgical exposure. A corticocancellous allograft was used to fill the defect following the reduction and fixation of posterior facet. Titanium locking plates and screws were used to maintain reduction. The patients were encouraged for a limited weight-bearing at six weeks postoperatively, if tolerated. All patients were able to full weight-bear at 12 weeks postoperatively. Clinical and radiological assessments were performed using the American Orthopaedic Foot and Ankle Society (AOFAS) and Maryland scores. Results: The mean follow-up was 19 months (range, 12 to 27 months). The AOFAS and Maryland scores were 89 and 88.46 points, respectively. The Böhler's angle showed 0.3° loss from early post-surgery to the last visit. Among the workers, all returned to work but one with Sanders type IV fracture and all retired patients returned to their daily activities. The functional status of the patient with Sanders type IV fracture was poor according to the AOFAS and Maryland criteria. Conclusion: Based on radiographic and clinical assessment, there was no unfavorable effect of early weight-bearing after calcaneal fracture surgery. Therefore, these results suggest that sufficient stability can be achieved by locking plates in comminuted calcaneal fractures, when early weight-bearing is recommended, even.
... Bezüglich der Effektivität beider Behandlungsalternativen existieren lediglich 4 experimentelle Untersuchungen an Kadaverfüßen. Während Stoffel et al. [55] zeigen konnten, dass eine geringere Deformierung durch die Anwendung einer winkelstabilen Platte stattfand, identifizierten Redfern et al. [41], Blake et al. [4] und Illert et al. [25] keine signifikanten Unterschiede im Bereich der Anzahl der Zyklen bis zum Versagen der Platte, der Implantatlockerung, der Fragmentverschiebung oder der Implantatsteifigkeit. Lediglich Illert et al. [25] konnten eine höhere Steifigkeit der nichtwinkelstabilen Platte nachweisen. Sie schlossen daraus, dass die Platte zunächst mit der Spongiosaschraube zur Erhöhung der Steifigkeit an den Knochen angepresst und anschließend winkelstabile Schrauben eingebracht werden sollten. ...
Article
Background Calcaneus fractures are still regarded as one of the most complicated fractures. In this paper, the current classifications and the status quo of therapy options for calcaneal fractures are provided. Classification Although a large number of classifications are available, no uniform classification is used in the clinical setting. Therapy Various options for treatment and concepts for follow-up treatments are reviewed and evaluated in an evidenced-based manner. While it appears that surgical treatment of complex fractures of the joint is superior to conservative therapy, the optimal surgical procedure remains unclear. Intraoperative evidence of the joint′s reposition is desirable. Conclusion Due to the difficulty and complexity of treatment, treatment in hospitals with high case loads of calcaneal fractures is likely to be beneficial for the patient.
... Schlussfolgernd werden winkelstabilen Implantaten am proximalen Humerus aufgrund des optimalen Lasttransfers am Knochen- Implantat-Interface bessere Retentionseigenschaften zugeschrieben [11]. Diese biomechanische Überlegenheit winkelstabiler Platten konnte neben der Anwendung am proximalen Humerus [8] auch für das distale Femur [5] , die proximale Tibia [9] und den Kalkaneus [12] nachgewiesen werden. Für distale Radiusfrakturen mit dorsaler Trümmerzone hingegen bestätigte sich ein solcher biomechanischer Vorteil winkelstabiler vs. nichtwinkelstabiler Platten nicht [14]. ...
Article
Zusammenfassung Die biomechanischen Vorteile winkelstabiler Implantate führten zu einer weiten Verbreitung im klinischen Alltag. Das Indikationsspektrum winkelstabiler Platten reicht von komplexen periartikulären Frakturen über meta- und diaphysäre Trümmerfrakturen, Umstellungsosteotomien bis hin zum Einsatz bei periprothetischen Brüchen. Besondere Vorteile bietet das Fixateur-interne-Prinzip bei der Frakturversorgung am osteoporotischen Knochen sowie in der Anwendung als Brückenplatte („bridging plate“) bei langstreckigen mehrfragmentären Schaftfrakturen zur elastischen Fixation und sekundären Frakturheilung über Kallusbildung. Als nachteilig sind sekundäre Schraubenperforationen des starren Implantatkonstruktes z. B. am proximalen Humerus, das Beibehalten jeder Distraktion, schwierige Materialentfernungen bei kaltverschweißten Schrauben und die höheren Implantatkosten anzusehen.
... Redfern et al (38) e Stoffel et al (39) , em estudos biomecânicos testando resistência, deformidade e carga suportada, utilizaram modelos de fraturas intra-articulares em peças de cadáveres para comparar a fixação utilizando placas bloqueadas ou não. Redfern et al (38) , em modelos experimentais com fraturas tipo IIB de Sanders, não encontraram vantagens entre a fixação da fratura com placa bloqueada ou com a fixação tradicional com a placa não bloqueada. ...
Article
Full-text available
OBJETIVO: Verificar as variáveis de distribuição da pressão plantar de pacientes submetidos a tratamento cirúrgico de fratura de calcâneo e correlacioná-las com duas diferentes vias de acesso cirúrgico. Métodos: Os autores estudaram 15 pacientes com idade entre 20 e 53 anos (média de 40,06 anos) que apresentaram fraturas intra-articulares do calcâneo, submetidos ao tratamento cirúrgico por duas vias de acesso cirúrgico, a via lateral e a via do seio do tarso. Avaliaram a distribuição da pressão plantar, correlacionando essas variáveis com as duas vias de acesso. A avaliação da distribuição da pressão plantar foi rea-lizada através do sistema Pedar (Novel, GmbH, Munique, Alemanha), verificando o pico máximo de pressão do retropé e do antepé do lado fraturado e do lado normal. RESULTADOS: A média das pressões máximas dos plantigramas do retropé dos pés operados pela via de acesso lateral e pela via curta não apresentou diferença estatística entre as duas vias de acesso (t=0,11; p=0,91), bem como a média das pressões máximas dos plantigramas do antepé também não mostrou diferença estatística significativa (t= -0,48; p = 0,64). CONCLUSÃO: Os autores concluíram que não houve diferença estatística entre as médias dos picos máximos de pressão do retropé e do antepé do lado operado, comparados com o lado normal, bem como não houve diferença estatística dessas variáveis comparadas com a via de acesso cirúrgico utilizada.
... Specialized forms of internal fixation devices, such as locking plates or intramedullary nails, have been shown to be superior to traditional methods of fixation in osteoporotic bone. [31][32][33][34][35][36][37][38] The limitations of this study include its small sample size, which makes the study underpowered when evaluating the relationship between age and BMD. Furthermore, the patients were not stratified by type of DM (type 1 or type 2), duration of DM, use of insulin, body mass index, or associated comorbidities that may affect BMD (ie, renal osteodystrophy). ...
Article
This prospective study was performed to compare calcaneal and lumbar bone mineral density (BMD) in individuals with and without diabetes mellitus. We compared bone density with the time from onset of Charcot's neuroarthropathy (CN) in patients with unilateral, nonoperative, reconstructive-stage CN. The final purpose was to investigate the role that sex, age, and serum vitamin D level may have in osseous recovery. Thirty-three individuals were divided into three groups: controls and patients with diabetes mellitus with and without CN. Peripheral instantaneous x-ray imaging and dual-energy x-ray absorptiometry were performed. The calcaneal BMD of patients with diabetes mellitus and CN was lower than that of the control group (P < .01) but was not significantly lower than that of patients with diabetes mellitus alone. There was no statistically significant difference in lumbar T-scores between groups. Women demonstrated lower BMD than did men (P = .02), but patients 60 years and older did not demonstrate significantly lower BMD than did patients younger than 60 years (P = .135). A negative linear relationship was demonstrated between time and BMD in patients with CN. The results of this study suggest that lumbar BMD does not reflect peripheral BMD in patients with diabetes mellitus and reconstructive-stage CN. This study has clinical implications when reconstructive osseous surgery is planned in patients with CN.
... Many studies demonstrated improved stability and fracture healing potential by use of locking plates. [4,5] However, in plating technique, screw failure is not a rare phenomenon, which mostly happens due to screw toggling, screw pullout, or screw fracture. [5,6] Therefore, cortical screw purchase is an important factor in the mechanical stability of fracture fixation. ...
Article
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Objectives: This study aims to assess five different cortical screw types using artificial femurs, under equated testing conditions. Materials and methods: We investigated the maximum force needed to cause deformation at screw-bone interface using fourth generation composite femurs by conducting separate pullout tests for each screw type. We normalized obtained results with traditional methods and cross-comparison. To conduct pullout tests dependent on screw dimensions, we eliminated the effect of bicortical bone thickness by equalizing the conditions of screw insertion. Results: Non-locking screws with larger diameter and pitch depth required larger pullout forces to be extracted, showing statistically superior performance compared to locking screws with smaller dimensions. However, the statistical differences between the absolute pullout forces decreased after the traditional normalization of the results. We proposed a new normalization method based on solid geometric reasoning. Conclusion: This novel approach showed that a screw type that appeared to show average performance, in fact, did not have statistically significantly different results than the top performers. Surgeons are not required to prefer larger dimension screws in small dimension host bones.
... Failure was defined by reaching the maximum load of 5000 N or a 0-degree gradient in the load deformation diagram. 19 The load deformation data of the hydraulic testing device were registered via MTS FlexTest 40 multipurpose testware software. Interfragmentary movement was detected by 2 charge-coupled device cameras connected to a computer. ...
Article
Full-text available
Background: Open reduction and internal fixation with a plate is deemed to represent the gold standard of surgical treatment for displaced intra-articular calcaneal fractures. Standard plate fixation is usually placed through an extended lateral approach with high risk for wound complications. Minimally invasive techniques might avoid wound complications but provide limited construct stability. Therefore, 2 different types of locking nails were developed to allow for minimally invasive technique with sufficient stability. The aim of this study was to quantify primary stability of minimally invasive calcaneal interlocking nail systems in comparison to a variable-angle interlocking plate. Material and methods: After quantitative CT analysis, a standardized Sanders type IIB fracture model was created in 21 fresh-frozen cadavers. For osteosynthesis, 2 different interlocking nail systems (C-Nail; Medin, Nov. Město n. Moravě, Czech Republic; Calcanail; FH Orthopedics SAS; Heimsbrunn, France) as well as a polyaxial interlocking plate (Rimbus; Intercus GmbH; Rudolstadt, Germany) were used. Biomechanical testing consisted of a dynamic load sequence (preload 20 N, 1000 N up to 2500 N, stepwise increase of 100 N every 100 cycles, 0.5 mm/s) and a load to failure sequence (max. load 5000 N, 0.5 mm/s). Interfragmentary movement was detected via a 3-D optical measurement system. Boehler angle was measured after osteosynthesis and after failure occurred. Results: No significant difference regarding load to failure, stiffness, Boehler angle, or interfragmentary motion was found between the different fixation systems. A significant difference was found with the dynamic failure testing sequence where 87.5% of the Calcanail implants failed in contrast to 14% of the C-Nail group (P < .01) and 66% of the Rimbus plate. The highest load to failure was observed for the C-Nail. Boehler angle showed physiologic range with all implants before and after the biomechanical tests. Conclusion: Both minimally invasive interlocking nail systems displayed a high primary stability that was not inferior to an interlocking plate. Clinical relevance: Based on our results, both interlocking nails appear to represent a viable option for treating displaced intra-articular calcaneal fractures.
... The determination of the treatment process is linked to the diagnosis and severity of the fracture. In recent years computed tomography (CT) has been used instead of radiographic methods [27][28][29][30][31] . In calcaneal fractures detailed evaluation of pathoanatomy with CT demonstrating the integrity of the joint surfaces and better understanding of the mechanisms of fracture formation have led to progress in classification and treatment. ...
Article
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Purpose: The aim of this study was to evaluate calcaneus angles in dry bones belonging to Turkish population. Materials and Methods: Dry calcaneal bones which age and sex were unknown belonging to Cukurova University Faculty of Medicine were used in this study. The photographs of the bones were taken under fixed light and distance, positioned like lateral direct graph, the Böhler (BA) and Gissane (GA) angles were measured according to the reference points using the digital design program (SketchUp 2016). Calculation sensitivity was 1/10°. Angle value distrubitons and left right relations were examined. After the measurements minimum-maximum, median and standart deviation values were obtained. Results: Total of 67 dry bones were clasified as left and right. The average BA was measured as (minimum-maximum); 29.68°±4.71° (20.00°-39.80°) on the right side and 31.54°±4.88° (20.20°-41.20°) on the left side. GA average was measured as (minimum-maximum); 102.96°±5.25° (93.70°-114.5°) on the right side, 103.89°±7.14° (93.10°-120.4°) on the left side. For both angles no significant difference was found between left and right calcaneus. Conclusions: Calcaneus angles may differ between races and populations. These angular values are important in determining calcaneus fractures. Base values of these angles are especially important in determining the baseline values which will be useful in practice. In literature the risk of fractures (especially displaced fractures) increases as the Böhler Angle and Gissane Angle approach the lower limits. Therefore, values obtained in this study will contribute establishing reference values in Turkish population.
... In the literature, the advantages and effectiveness of locking plates are very clear. [21][22][23] However, the necessity for and effectiveness of grafting is still a controversial issue. [9][10][11][12] In addition to the effects of filling defects, grafting also has the effect of providing mechanical support and promoting bone healing. ...
Article
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Objective The aim of this study was to determine whether tri-cortical iliac bone autografting provided extra benefit for the stabilization in Sanders Type 3–4 calcaneal fractures fixed with locking plate. Materials and methods The study included 29 calcaneal fractures (Sanders Type 3/4=15/14). All fractures were fixed with locking plate using the extended lateral approach. Bone grafts were used in 16 (Group A; Sanders Type 3/4=7/9) and not used in 13 (Group B; Sanders Type 3/4=8/5) calcaneal fractures. As a grafting material, only tri-cortical iliac crest bone autograft was used. All operations were performed by the same surgeon. The same locking plate was used in all fractures. Calcaneal height and angle of Bohler and Gissane were measured in early postoperative and final control radiographs in both groups. Clinical evaluations were performed using the American Orthopedic Foot and Ankle Society ankle hind foot scale. Results There was no difference between the groups in terms of clinical results. Radiologically, the degree of change in Bohler’s angle, Gissane’s angle, and calcaneal height was not different between the groups. Conclusion Bone grafting does not affect the clinical and radiologic outcomes in Sanders Type 3–4 calcaneal fractures fixed with locking plate, and they provide no extra benefit to the stabilization. We think that fixation using locking plate is adequate and there is no need for bone grafting.
... It is notable that the regions where the stress exceeded the allowable stress were located in the screw neck immediately below the plate. This was consistent with the results of three LP construct biomechanical studies (Stoffel et al. 2007;Bottlang, Doornink, Byrd, et al. 2009;). They reported that all LP constructs failed by screw breakage under torsion. ...
Article
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With the emerging concerns for more flexible and less stiff bridge constructs in the interest of stimulating bone healing, the technique of far cortical locking has been designed to reduce the stiffness of locked plating (LP) constructs while retaining construct strength. This study utilized simulation with diaphyseal bridge plating biomechanical models to investigate whether far cortical locking causes larger screw fracture risk than LP during rehabilitation. The fracture risk of the screws in the far cortical locking constructs increases in the non-osteoporotic and osteoporotic diaphysis compared with the screws in the LP constructs.
... However, the difference between ultimate displacement and work to failure was not significant in their study. 13 Rak et al confirmed the benefits of implanting locking compression plates in displaced intra-articular fractures of calcaneus over non-locking calcaneal plates for all Sanders types of intra-articular fractures. 14 ...
Article
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Introduction: Calcaneal fractures are a common fracture in the hind foot caused by a high energy trauma, such as a fall or motorcycle accident. For ideal functional results, anatomical reconstruction and restoration of the joint should be achieved with the restoration of articular congruity of the subtalar joint. This study was planned to assess the problem of wound complications and final outcome of fracture calcaneus. Aims & Objectives: To evaluate the results of plating of calcaneus by lateral approach. Methods: We retrospectively evaluated 12 patients of calcaneus fracture who were treated at Department of Orthopaedics, Govt. Medical College & Hospital, Patiala, between January 2017 to December 2019. These patients were treated by extensile lateral approach and calcaneus plate fixation. The inclusion criteria were intra-articular fractures of the calcaneus. All findings and complications were recorded and managed accordingly. Results: 8.3% patients had wound edge necrosis and required debridement which healed with dressings. 1(8.3%) patient had a serious wound dehiscence. Excellent result was achieved in 7 (58.3%) patients. Good results were seen in 3 (25%) patients. 1 patient (8.3%) had a fair result. 1 patient (8.3%) had a poor result. Conclusion: The treatment of calcaneus fracture by open reduction and locking plate is a satisfactory method. There is good outcome and better patient satisfaction.
... 5 Regarding surgical treatment options using internal fixation, including lag screws, Kirschner wires, steel cables, anchors, and steel plates, all of these techniques have their shortcomings as well as strengths. [6][7][8][9] The calcaneal tuberosity is the stop point of the Achilles tendon. Due to the traction of the Achilles tendon and osteoporosis, a large number of reports have shown that a series of complications such as skin flap necrosis and failure of internal fixation after surgery often cause nonunion or malunion of calcaneal tuberosity fractures. ...
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Ding Xu,* Weigang Lou,* Ming Li, Jianming Chen Department of Orthopedic Trauma Surgery, Ningbo No.6 Hospital, Ningbo, People’s Republic of China*These authors contributed equally to this workCorrespondence: Ding Xu Email xuding831129@126.comAbstract: Due to the traction of the Achilles tendon and osteoporosis, a large number of reports have shown that a series of complications such as skin flap necrosis and failure of internal fixation after surgery often cause nonunion or malunion of calcaneal tuberosity fractures. At the same time, there is no uniform standard for the operative procedure in the treatment of the avulsion fractures of the calcaneal tuberosity. We presented a new technique for the treatment of avulsion fractures of the calcaneal tuberosity, which is fixed with a 180-degree microplate. We aim to provide a simple, safe, and strong internal fixation technique for avulsion fractures of the calcaneal tuberosity as one of the treatment options.Keywords: 180-degree annular internal fixation, avulsion fractures of the calcaneal tuberosity, new technique
... We used strong internal fixation and bone grafting in the osteotomy area to promote the healing of the osteotomy as other surgeons do. Studies have shown that [13,14] strong internal fixation materials can promote fracture healing and to make patients to walk as soon as possible, which is conducive to the recovery of lower limb function. Wedgeshaped osteotomy on the medial tibia will lead to a wedgeshaped bone defect area, and the larger the expansion angle, the larger the defect volume, which may increase the risk of nonunion of the osteotomy area. ...
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Purpose: To explore the clinical effect of electroacupuncture in promoting the healing of the osteotomy area after high tibial osteotomy. Methods: 50 patients with knee osteoarthritis who underwent open wedge high tibial osteotomy (OWHTO) were selected and randomly divided into the observation group and control group. The control group got the common postoperative treatment, and the observation group was added electroacupuncture from the 3rd day after the operation on the basis of the control group. The electroacupuncture acupoints were selected SP10, ST34, ST32, EX-LE2, ST40,KI6, KI3, SP6, and ST41, once a day, and 14 days were a course of treatment. And then we contrasted the index of the Lane-Sandhu X-ray score, the skin incision healing time, the swelling subsided time, Visual Analogue Scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index Score (WOMAC), and Lysholm in different time. Results: The Lane-Sandhu X-ray score of the observation group was better than that of the control group at all time points (P < 0.05), and the time to achieve bone healing was about 2 weeks earlier than that of the control group. The skin healing and swelling were the subsided time in the osteotomy area. Both were better than the control group, and the difference was statistically significant (P < 0.05). The VAS score, WOMAC score, and Lysholm score of the two groups were significantly improved compared with preoperatively, and the difference was statistically significant (P < 0.05). The improvement of the observation group's VAS score, WOMAC score, and Lysholm score at 1 week, 4 weeks, and 8 weeks after the end of the treatment course was better than that of the control group, and the difference was statistically significant (P < 0.05). Conclusion: Electroacupuncture can quicken the healing of bone tissue and surrounding soft tissues in the osteotomy area after high tibial osteotomy, and at the same time, it can help the relief of knee joint pain and improve knee joint function.
... A number of implants, like the Kirschner wires (K-wires), absorbable screws (AS), cannulated screws (CS), and plate-screw system (PSS), have been successfully used for the internal fixation of calcaneal fractures [6][7][8][9]. The stability of the fixation is an important factor in maintaining the position of the reduction, but previous biomechanical studies were mostly concerned about plate selection and implant type [10][11][12][13][14]. The biomechanical stability of different devices has not yet been well investigated and there is no clear evidence which one will produce the best stability for calcaneal fractures. ...
Article
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Background Calcaneal fractures account for around 2% of all fractures and most of them are intra-articular fractures. Many implants have been used in the fixation of calcaneal fractures, but their biomechanical stability has not yet been well investigated. The aim of this study was to compare the primary stability of four fixations of calcaneal fracture. Methods Eight cadaveric calcaneus samples were used to simulate the Sanders’ types III fracture pattern and fixed through four different implants, namely, K-wires, cannulated screws (CS), absorbable screws (AS), and plate-screw system (PSS). Each specimen was then placed into a custom-made jig and was loaded through a material testing machine to simulate the physiological condition. The primary stability was measured in the vertical direction as the stiffness and anterior–posterior direction as the calcaneocuboid force. One-way analysis of variance was used for data analysis. ResultsThe results showed the highest stiffness of 634 (383–891; SD 226) N/mm in the intact model. It was significantly higher than the models fixed with K-wires, CS or PSS. There was no significant difference in vertical stiffness between fractures fixed with AS and the intact model or other fixed models. The intact model showed the lowest calcaneocuboid force of 153 (120–218; SD 39) N, while the fractures fixed with AS showed the greatest force of 242 (146–398; SD 84) N. The significance was only detected between these two models. Conclusions The global stiffness was similar when the calcaneal fractures were fixed by K-wires, CS and PSS. The stability of the AS fixation differed along both the vertical and anterior–posterior directions, and was greatly influenced by the bone quality. AS for fracture fixation should be designed with greater strength and pull-out resistance.
... A cadaveric study compared a conventional calcaneal plate to a low-profile locking plate on fracture reduction and failure of implant with cyclical loading. The locking plate showed a lower deformation rate and significantly higher load to failure compared with the conventional one [43]. Another group looked at the differences between uniaxial and polyaxial screws in locking plates using calcaneal saw bones and found that during cyclical loading the plate with the polyaxial screws showed less displacement and hence increased stability [44]. ...
Article
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This review article on the current management for calcaneal fractures discusses the advantages and disadvantages of different treatment options including the problems encountered. Controversies are described and the evidence reviewed. The management of some types of displaced intra-articular calcaneal fractures remains contentious; is there a preferred stabilisation method for each type of calcaneal fracture? How constant is the “constant fragment” in an intra-articular calcaneal fracture and what is the evidence for primary arthrodesis and what is its place in these fractures?
... Surgical techniques and hygiene concepts have undergone significant developments since the 1990s and early 2000s and might have led to a reduction in incidences of IWH [6]. Modern implants, such as low-profile locking plates, have been shown to provide improved stability compared to older implants [24,25]. As good balance between biomechanical stability and micromovements is a key element for successful secondary fracture and primary wound healing, modern implants may have contributed to a reduction in complication rates, including IWH [26]. ...
Article
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Purpose Surgically treated calcaneal fractures have a high risk of postoperative wound healing complications and a prolonged length of hospital stay (LOS). The aim of this study was to identify predictor variables of impaired wound healing (IWH) and LOS in surgically treated patients with isolated calcaneal fractures. Methods This retrospective cohort study analyzed data on patients aged 18 years or older who were admitted to a level I trauma center with isolated calcaneal fractures between 2008 and 2018. Multivariable regression models were used to identify predictor variables. Results In total, 89 patients (age: 45.4 years; SD: 15.1) were included. In 68 of these patients, low-profile locking plate osteosynthesis was performed, and a minimally invasive approach (MIA) (percutaneous single screws/K-wire or low-profile locking plating via a sinus tarsi approach) was applied in 21 patients. Multivariable regression analysis revealed that a higher preoperative Böhler’s angle (β = − 0.16 days/degree, 95% CI [− 0.25, − 0.08], p = 0.004) and MIA (β = − 5.04 days, 95% CI [− 8.52, − 1.56], p = 0.002) reduced the LOS. A longer time-to-surgery (β = 1.04 days/days, 95% CI [0.66, 1.42] p = 0.001) and IWH increased the LOS (β = 7.80 days, 95% CI [4.48, 11.12], p = 0.008). In a subsequent multivariable regression analysis, two variables, open fractures (OR: 14.6, 95% CI [1.19, 180.2], p = 0.030) and overweight (BMI > 24) (OR: 3.65, 95% CI [1.11, 12.00], p = 0.019), increased the risk of IWH. Conclusion Advanced treatment algorithms for open fractures are needed to reduce the risk of IWH.
Article
Calcaneal fractures represent 2% of all fractures and account for approximately 60% of all tarsal injuries. Motor vehicle collisions and falls are the major causes of these large force compression injuries, causing widening of the heel, loss of heel height, and articular surface displacement. A correlation has been shown between restoration of normal anatomy and satisfactory functional outcome. Once the basic principles of calcaneal fractures are understood, including the anatomy, the radiographic findings, and the challenges that these complicated fractures present, the physician can then be ready with the armamentarium that allows for a patient-specific and injury-specific plan.
Article
To determine whether locking plates offer an advantage in fixation of fractures in osteoporotic humeral bone. Biomechanical testing of 18 matched pairs of osteoporotic human cadaver humeri plated posteriorly with either all locked or all nonlocked screws. An established protocol was used to test the constructs with torque applied to a peak of ±10 Nm for 1000 cycles at 0.3 Hz or until failure. Eighteen pairs were tested for failure, 11 pairs were tested for cycles survived, and 10 pairs were tested for stiffness. University biomechanical laboratory. Percentage surviving testing, mean cycles survived, and stiffness. We observed catastrophic failure of the constructs in 47% of the samples. Humeri plated with nonlocking plates failed at a higher rate than those with locking plates (67% nonlocking vs 28% locking, n = 18 pairs, P = 0.008). Locking constructs also outperformed nonlocking constructs in mean cycles survived (707 cycles locking, 345 cycles nonlocking, n = 11 pairs, P < 0.05) and stiffness at 10 cycles (0.853 Nm/degree locking vs 0.416 Nm/degree nonlocking, n = 10 pairs, P < 0.001). Locking plates were shown to provide improved mechanical performance over nonlocking plates in torsional cyclic loading in a osteoporotic cadaveric fracture model. Our results confirm general conclusions of previous work that used a synthetic bone model of osteoporosis, but we found a high rate of catastrophic failure, questioning the validity of the previously published synthetic model of osteoporosis (overdrilling of synthetic bone) for this application.
Article
Objective: To compare the accuracy of reduction and the biomechanical characteristics of canine acetabular osteotomies stabilized with locking versus standard screws in a locking plate. Study design: Ex vivo biomechanical study. Sample population: Cadaveric canine hemipelves and corresponding femurs (n=10 paired). Methods: Transverse acetabular osteotomies stabilized with 5-hole 2.4 mm uniLOCK reconstruction plates using either 2.4 mm locking monocortical or standard bicortical screw fixation (Synthes Maxillofacial). Fracture reduction was assessed directly (craniocaudal acetabular width measurements and gross observation) and indirectly (impression casts). All constructs were fatigue-tested, followed by acute destructive testing. All outcome measures (mean+/-SD) were evaluated for significance (P<.05) using paired t-tests. Results: Craniocaudal acetabular diameters before and after fixation were not significantly different (21.9+/-1.2 and 21.5+/-1.2 mm; P=.45). No significant differences were observed in acetabular width differences between pre- and postoperative fixation between groups (locking -0.4+/-0.4 mm; standard -0.4+/-0.3 mm; P=.76). Grossly, there was no significant difference in the repairs and impression casts did not reveal a significant (P=.75) difference in congruency between the groups. No significant differences were found in fracture gap between groups either dorsally (locking 0.38+/-0.23 mm versus standard 0.22+/-0.05 mm; P=.30) or ventrally (locking 0.80+/-0.79 mm versus standard 0.35+/-0.13 mm; P=.23), and maximum change in amplitude dorsally (locking 0.96+/-2.15 mm versus standard 0.92+/-0.89 mm; P=.96) or ventrally (locking 2.02+/-2.93 mm versus standard 0.15+/-0.81 mm; P=.25). There were no significant differences in stiffness (locking 241+/-46 N/mm versus standard 283+/-209 N/mm; P=.64) or load to failure (locking 1077+/-950 N versus standard 811+/-248 N; P=.49). Conclusion: No significant differences were found between pelves stabilized with locking monocortical screw fixation or standard bicortical screw fixation with respect to joint congruity, displacement of fracture gap after cyclic loading, construct stiffness, or ultimate load to failure. Clinical relevance: There is no apparent advantage of locking plate fixation over standard plate fixation of 2-piece ex vivo acetabular fractures using the 2.4 mm uniLOCK reconstruction plate.
Article
The purpose of this study was to compare the biomechanical stability obtained by using our technique featured an anatomical plate and compression bolts versus that of the conventional anatomic plate and cancellous screws in the fixation of intraarticular calcaneal fractures. Eighteen fresh frozen lower limbs of cadavers were used to create a reproductive Sanders type-III calcaneal fracture model by using osteotomy. The calcaneus fractures were randomly selected to be fixed either using our anatomical plate and compression bolts or conventional anatomic plate and cancellous screws. Reduction of fracture was evaluated through X radiographs. Each calcaneus was successively loaded at a frequency of 1 Hz for 1000 cycles through the talus using an increasing axial force 20 N to 200 N and 20 N to 700 N, representing the partial weight bearing and full weight bearing, respectively, and then the specimens were loaded to failure. Data extracted from the mechanical testing machine were recorded and used to test for difference in the results with the Wilcoxon signed rank test. No significant difference was found between our fixation technique and conventional technique in displacement during 20-200 N cyclic loading (P=0.06), while the anatomical plate and compression bolts showed a great lower irreversible deformation during 20-700 N cyclic loading (P=0.008). The load achieved at loss of fixation of the constructs for the two groups had significant difference: anatomic plate and compression bolts at 3839.6±152.4 N and anatomic plate and cancellous screws at 3087.3±58.9 N (P=0.008). There was no significant difference between the ultimate displacements. Our technique featured anatomical plate and compression bolts for calcaneus fracture fixation was demonstrated to provide biomechanical stability as good as or better than the conventional anatomic plate and cancellous screws under the axial loading. The study supports the mechanical viability of using our plate and compression bolts for the fixation of calcaneal fracture.
Article
This study evaluated the effects of locking vs nonlocking configuration on the biomechanical performance of a calcaneal reconstruction plate in an osteoporotic cadaveric model. A Saunders II B type calcaneal fracture was created in ten matched pair of cadaveric calcanei. Each pair was fixed with the Ascension calcaneal reconstruction plate using either locking or nonlocking screws in the same hole pattern. Specimens were axially loaded for 1000 cycles through the talus followed by load to failure. Statistical comparisons were made between the locking and nonlocking constructs on the displacements during cyclic loading as well as construct stiffness and load achieved at selected fragment displacements. No significant difference was detected between the locking and nonlocking constructs in displacement during cyclic loading (p > 0.2) for the numbers available. Similarly no significant difference was found in stiffness of the constructs between the groups: 445.7 ± 148.8 (N/mm ± SD) for the locking plate and 395.2 ± 127.7 for the nonlocking plate (p > 0.14). The load achieved at 2 mm displacement of the posterior fragment for the two groups were not different: locking plate at 744.6 ± 237.2 N and nonlocking plate at 739.3 ± 269.7 N (p > 0.99). This study did not reveal a mechanical advantage to locking technology for calcaneal fractures with the selected plate and fracture model. While locking plate technology has shown mechanical advantages for fracture management in other osteoporotic models, in our fracture model and plating construct, this was not found. It is still unclear which fixation technique is most beneficial in these calcaneal fractures.
Article
Understanding the basic biomechanical principles of surgical stabilization of fractures is essential for developing an appropriate preoperative plan as well as making prudent intraoperative decisions. This article aims to provide basic biomechanical knowledge essential to the understanding of the complex interaction between the mechanics and biology of fracture healing. The type of healing and the outcome can be influenced by several mechanical factors, which depend on the interaction between bone and implant. The surgeon should understand the mechanical principles of fracture fixation and be able to choose the best type of fixation for each specific fracture.
Article
Purpose of review: The aim of this article is to present recent publications regarding diagnosing and treating calcaneus fractures. Recent findings: Increased awareness of occult fractures, the role of plain film imaging, computed tomography, and MRI improve early diagnosis and guide decision-making. The reliability of fracture classification systems may confound the conclusions of clinical studies relying on these classification systems. Studies reporting the results of minimally invasive management continue to demonstrate scant complications. Improving reduction through adjuncts to joint surface visualization may improve long-term functional outcomes. A protocol for decision-making in open fractures of the calcaneus defines prognostic factors. Bone graft substitutes may reduce subsidence following minimally invasive procedures. Biomechanical studies explore the potential benefit of locked plate constructs. Strategies for management of late complications of arthrosis and malunion are reviewed. Summary: Recent trends in minimally invasive surgery, noninvasive imaging, and understanding the biomechanics of fixation constructs suggest the evolution of new decision-making and treatment philosophies in the management of calcaneus fractures.
Article
The aim of this biomechanical cadaver study of calcaneal fractures was to investigate whether a locking calcaneal plate provides more stiffness in osteoporotic bone compared to a non-locking plate. Sixteen fresh frozen bone mineral density (BMD)-matched cadaver feet were tested in a four-part model of a Sanders Type IIB calcaneal fracture. The fractures were fixed either with a non-locking AO (Sanders) plate or an interlocking AO plate (Synthes, Paoli, PA) to the lateral calcaneal wall with six screws. Specimens were subjected to cyclic loading which was increased stepwise to full body weight. Displacement of the posterior facet fragment was measured with an optical tracking system in the sagittal and transverse planes. No statistically significant differences were observed between the non-locking and the locking plates with respect to number of cycles to failure or 1-mm displacement of the posterior facet. The initial stiffness was significantly higher for non-locking plates. In osteoporotic bone, the greater stiffness of the screw-locking-plate construct was offset by the smaller diameter of the screw threads and the lower friction between the plate and bone when a locking plate was used. In clinical practice, the plate should first be compressed to osteoporotic bone with cancellous screws and at least two screws should be placed in the anterior process and in the tuberosity of the calcaneus.
Article
Locked plating and nonlocked plating rely on different biomechanical principles for success. Therefore, it should be no surprise that differences in performance can be observed, especially in specific clinical situations. The current consensus is that locked plating is beneficial in situations which require support of end segment fractures that are prone to varus/valgus collapse, in diaphyseal or metaphyseal fractures in osteoporotic bone, and in plating of fractures where, due to anatomic constraints, compression plates may not be placed on the tension side of the fracture. These fractures are often comminuted and commonly occur in elderly patients with poor bone density. The objective of this review is to examine the research studies that compare the biomechanical performance of locked and nonlocked plates for the specific application of difficult diaphyseal or metaphyseal osteoporotic fractures.
Chapter
Das zentrale Kapitel 5 behandelt in systematischer Weise die Frakturen und posttraumatischen Fehlstellungen der 28 Knochen des Fußes vom Talus bis zu den Sesambeinen. Die Konsequenzen von Fehlheilungen einzelner Fußknochen und Gelenkverwerfungen auf die komplizierte Statik des Fußes als Ganzes werden detailliert beschrieben und Lösungswege für Korrekturoperationen anhand therapierelevanter Algorithmen dargestellt. Schließlich wird auch auf Stressfrakturen und Überlastungsschäden eingegangen, welche an keinem anderen Skelettabschnitt so häufig auftreten, wie am Fuß.
Article
This paper analyses the suitability of a system comprising a Dynamic Compression Plate (DCP) and Screw Locking Elements (SLEs) to allow sufficient interfragmentary motion to promote secondary bone healing in osteoporotic fractures.Four fixation systems were mounted on bone-simulating reinforced epoxy bars filled with solid rigid polyurethane foam. Group 1, used for comparison purposes, represents a system comprised of a Locking Compression Plate (LCP) and eight locking screws. Groups 2 and 3 represent a system comprised of a DCP plate with eight cortical screws and two SLEs placed on the screws furthest from (group 2) and nearest to (group 3) the fracture. Group 4 represents the system comprised of a DCP plate with SLEs placed on all eight cortical screws. Cyclic compression tests of up to 10,000 load cycles were performed in order to determine the parameters of interest, namely the stiffnesses and the interfragmentary motion of the various configurations under consideration. Tukey's multiple comparison test was used to analyse the existence or otherwise of significant differences between the means of the groups.At 10,000 cycles, interfragmentary motion at the far cortex for group 2 was 0.60 ± 0.04 mm and for group 3 0.59 ± 0.03 mm (there being no significant differences: p = 0.995). The mean interfragmentary motion at the far cortex of the LCP construct was 70% less than that of the two groups with 2SLEs (there being significant differences: p = 1.1 × 10−8). In the case of group 4 this figure was 45% less than in groups 2 and 3 (there being significant differences: p = 5.6 × 10−6). At 10,000 cycles, interfragmentary motion at the near cortex for group 2 was 0.24 ± 0.06 mm and for group 3 0.24 ± 0.03 mm (there being no significant differences: p = 1.000). The mean interfragmentary motion at the near cortex of the LCP construct was 70.8% less than that of the two groups with 2SLEs (there being significant differences: p = 0.011). In the case of group 4 this figure was 66.7% less than in groups 2 and 3 (there being significant differences: p = 0.016). The mean stiffness at 10,000 cycles was 960 ± 110 N mm−1 for group 2 and 969 ± 53 N mm−1 for group 3 (there being no significant differences: p = 1.000). For group 1 (the LCP construct) the mean stiffness at 10,000 cycles was 3144 ± 446 N mm−1, 3.25 times higher than that of groups 2 and 3 (there being significant differences: p = 0.00002), and 1.6 times higher than that of the DCP + 8SLEs construct (1944 ± 408 N mm−1, there being significant differences: p = 0.007).It is concluded that using the DCP + 2SLEs construct sufficient interfragmentary motion is ensured to promote secondary bone healing. However, if too many SLEs are used the result may be, as with the LCP, an excessively rigid system for callus formation.
Article
Met deze review willen wij proberen inzicht te geven in de verschillende mogelijkheden en problemen die kunnen optreden bij het behandelen van een patiënt met een calcaneusfractuur. Door adequate diagnostiek en behandeling kan geprobeerd worden blijvende invaliditeit (ten gevolge van infectie, secundaire artrose, non/ malunion) te voorkomen, maar ook bij een optimal behandeling bestaat er een grote socio-economische impact. Naast de botschade door de fractuur zijn bij dit soort fracturen de weke delen bijzonder belangrijk voor de behandelingsopties. Het doel van de behandeling is het reconstrueren van de verschillende gewrichtsvlakken en de vorm van de calcaneus. In deze review bespreken wij de anatomie, classificatie, diagnostiek en behandeling van calcaneusfracturen.
Article
Calcaneal fractures are the most common fractures of the tarsal bones. The stability of fixation is an important factor for successful reconstruction of calcaneal fractures. The purpose of this study was to analyze the biomechanical influence of plate fixation with different combinations of locking and nonlocking screws during early weight-bearing phase. A three-dimensional FE foot model was established using ANSYS software, which comprised bones, cartilages, plantar fascia, and soft tissue. Calcaneal plate was fixed with whole locking (WLS), whole nonlocking (WNS), and hybrid screw configurations for FE analysis. The WNS generated a 6.1° and 2.2° Bohler angle decrease compared with the intact model and WLS (WNS: 18.9; WLS: 21.1; intact: 25.0°). Some hybrid screw configurations (Bohler angle: 21.5° and 21.2°) generated stability similar to WLS. The FE results showed that the fragments at the posterior facet and the posterior tuberosity sustained more stress. This study recommends that the hybrid screw configuration with at least four locking screws, two at the posterior facet fragment and two at the posterior tuberosity fragment, is the optimal choice for the fixation of Sanders type IIB calcaneal fractures.
Article
Background: The optimal treatment of displaced intraarticular calcaneal fractures remains challenging. Currently, there is no uniform method to treat such fractures. The purpose of this study was to compare the radiographic and clinical outcome of nonlocking plates and locking plates in the treatment of intraarticular calcaneal fractures. Methods: A retrospective comparative study was performed including 42 patients with intraarticular calcaneal fractures that were treated by nonlocking plate (n = 18) or locking plates (n = 24) between January 2010 and June 2012. Radiological and functional outcomes were compared between the 2 groups. Results: At the final follow-up, all fractures were healed, and the patients with a locking plate had a significantly better Bohler's angle and Gissane's angle compared with the nonlocking plate group (P < .05). No complications occurred for the patients in the locking plate group, and 3 patients in the nonlocking plate group had implant loosening that led to loss of reduction (P < .05). The average American Orthopaedic Foot and Ankle Society hindfoot score in the locking plate group was significantly higher than that in the nonlocking plate group (P < .05). No statistically significant difference between the 2 groups was found regarding SF-36 (P > .05). Conclusion: This study supports the view that locking plates may provide better stability and functional recovery in the treatment of intraarticular calcaneal fractures. Level of evidence: Level III, comparative case series.
Research
Campbell's Operative Orthopaedics 4-Volume Set, 13th Edition Chapter 88 translation
Article
Given the high rates of wound complications with a standard lateral extensile incision, small dual incision techniques might result in less soft tissue destruction. The goal of the present study was to compare the biomechanical performance between a single locking plate and a dual locking plating system for an intra-articular calcaneal fracture model. A Sanders IIB type joint depression calcaneal fracture was created in 10 paired, fresh-frozen, cadaveric calcanei (age 47 ± 12, range 35 to 78 years). The calcanei of each pair were randomly assigned for fixation using either a lateral locking reconstruction plate or lateral and medial locking reconstruction plates. The specimens were axially loaded in cyclic fashion for 1000 cycles, followed by load to failure. The relative fragment movement was monitored optically in both the sagittal and the coronal planes. The amount of overall construct displacement increased with cycling, although no difference was found between the plating techniques. For fragment movement during cycling, the lateral joint fragment migrated anteroinferiorly along the fracture line relative to the tuberosity fragment for dual plated specimens by a small, but statistically significant, amount. This same translation was smaller for lateral plated specimens but was not found to be significant. During load to failure testing, no statistically significant differences were found for construct stiffness. A tendency was seen toward more interfragmentary motion in the sagittal plane (lateral joint fragment movement relative to the fracture line), with less movement overall in the coronal plane (anterior fragment translation and twist) for dual plating, although the difference from the lateral plate was not statistically significant. The present study demonstrated that for this calcaneal fracture model, the dual plating technique experienced a small amount of fragment translation during cycling that was significantly different statistically from that with lateral plating but was not clinically relevant. During the load to failure, the dual plating technique was comparable to the lateral plate. Thus, dual plating could be a viable biomechanical option for fracture reduction if avoidance of a large extensile lateral approach associated with lateral plating is warranted. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.
Article
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Complex distal tibia fracture involving the articular surface poses a significant challenge to treat due to the need for stable fracture fixation that concurrently prevents articular displacement during motion. While several implant designs have been suggested to overcome this issue, the superiority of one design over the other has not been previously demonstrated. This study compared the stability provided by two commonly used implants (anterolateral plate (ATL) vs. medial distal tibia plate (MDT)) in treating these types of fracture. A three dimensional model of a six-part fracture fragment involving the distal tibia was reconstructed and simulated using computer aided software. Loading was applied to the model during swing phase gait. The model was fixed in all degree of freedom on bone fragment number 5 (central fragment). Simulated data from finite element analysis was used to determine the stresses in equivalent von Mises stress values (EVMS) whilst displacement of the fragments was measured in mm. The stresses subjected to the ATL and the MDT were 8.70 MPa and 5.62 MPa, respectively (p < 0.05). MDT caused less displacement of bone fragments as compared to ATL (0.22 ± 0.001 vs. 2.05 ± 0.019; p < 0.001). Fracture fixation using MDT provided superior stability and reduced fragment displacement than ATL during motion.
Article
Aim: The internal osteosynthesis of calcaneus fractures is implemented by pursuing the principle of anatomic reduction and stable synthesis, in order to obtain a cure with restoration morphological and biomechanical structures damaged while enabling early mobilization of articular structures. Aim of the work was to assess the resources currently available to the surgeon in light of their claims, the advantages and disadvantages in the use and its economic cost. Methods: The implants and materials used in the surgical synthesis of 85 calcaneus fractures between January 2003 and December 2010 at UOC of Traumatology, Department of Orthopedics and Traumatology of the ASO CTO/Maria Adelaide in Turin have been assessed and a systematic analysis of the results obtained by entering key words as "rearfoot", "surgery", "calcaneus" and "osteosynthesis" by the Internet search engines "PubMed" and "Google" was conducted. Results: Implants and materials now available are Kirschner wires, free screws, systems of plates and screws, rods and screws in PLLA and injectable bone substitutes. Conclusion: A stable osteosynthesis is the most important condition for avoiding to employ bone grafts, thus reducing the time for surgery and consequently the risk of infection. Plate and screws, especially most recent locking plate, is the golden standard to obtain a good stability in ORIF of articular fractures. Other implants have to be used in well-encoded cases, and the choice of the implant is based not only on the type of lesion but also on the inherent technical characteristics.
Article
The use of a locking plate eliminates excessive pressure on bone for anatomical reduction and thus preserves the periosteal blood supply, which is important for fracture healing. The far-cortical locking technique with a semi-rigid locking screw reduces structural stiffness and parallel motion, allowing uniform callus formation at the fracture site. Although previous studies demonstrated the superior clinical and biomechanical outcomes of semi-rigid locking screws over rigid ones, it is unclear whether a gap between the plate and bone should be preserved in the far-cortical locking technique. The present study conducted finite element analyses with mechanical calibration to clarify the influence of a plate-bone gap on the biomechanical performance of the far-cortical locking technique. A simulated mid-shaft fracture model was fixed using a locking plate and six semi-rigid locking screws. The plate-bone distance was 0 to 2 mm and the axial compressive load was 500 N. Gliding guidance at the plate-bone interface enhanced parallel intersegmental motion but reduced intersegmental movement, which is a mechanical stimulant for callus formation, and may increase pressure on the bone. Screw stresses increased with increasing plate-bone gap distance. For the far-cortical locking technique, the results suggest a minor plate-bone gap should be preserved. Engagement between the plate and bone should be avoided both before and after the application of mechanical load.
Article
Open reduction and internal fixation (ORIF) with plate is the standard treatment for displaced intra-articular calcaneal fractures. We constructed a three-dimensional complete foot finite element model, which was also modified to evaluate the biomechanical effect of Sanders IIB tongue-type calcaneal fracture treated by ORIF with locking plate. We compared plates with locking screws (LSs) and those with non-locking screws (NSs). Static standing was simulated by applying ground reaction force and the pulling force of the Achilles tendon. ORIF with plate using NS or LS provided good stability for Sanders IIB tongue-type calcaneal fracture and might allow light touch weight-bearing in the early postoperative period.
Article
Background: The extensile lateral approach (ELA) has been considered to be a standard approach for displaced intra-articular calcaneal fractures (DICF) because it provides excellent exposure and allows direct reduction of the depressed posterior facet fragment. But continuous retraction during surgery needs sufficient manpower and may cause ischemia. Failure of rigid fixation of DICF will not allow for early weight bearing and may lead to a loss of reduction. To avoid these disadvantages, this study presents open reduction assisted with an external fixator and internal fixation with a calcaneal locking plate. Methods: A series of 58 patients with 62 DICFs were treated over a period of 49 months. All patients were clinically and radiologically followed up with a mean follow-up of 35 (range 29-42) months. Clinical follow-up included visual analog scale (VAS), the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score, and ability to work. Radiologic follow-up included axial and lateral radiographs and measurements of the Bohler angle and Gissane angle. Results: At the final follow-up, all fractures had healed. The mean VAS score was 2.9 (range 0 to 8, SD 1.9) and the average AOFAS score was 71 (range 55-85, SD 8.1). The mean postoperative Bohler angle immediately after the surgery was 28.3 degrees (range 13.0-44.6, SD 7.0), which decreased to 27.5 degrees (range 12.2-43.3, SD 7.0) at the final follow-up, and the mean postoperative Gissane angle after the surgery was 116.3 degrees (range 94.9-131.5, SD 9.0) which finally increased to 118.4 degrees (range 94.5-135.8, SD 9.3). No statistically significant differences regarding Bohler and Gissane angles were found between different Sanders fracture types ( P>.05). Conclusion: The presented operative technique was found to provide comparable reduction of Sanders type II-IV injuries. Level of evidence: Level III, case control study.
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Background Decreasing the stiffness of locked plating constructs can promote natural fracture healing by controlled dynamization of the fracture. This biomechanical study compared the effect of 4 different stiffness reduction methods on interfragmentary motion by measuring axial motion and shear motion at the fracture site. Methods Distal femur locking plates were applied to bridge a metadiaphyseal fracture in femur surrogates. A locked construct with a short-bridge span served as the nondynamized control group (LOCKED). Four different methods for stiffness reduction were evaluated: replacing diaphyseal locking screws with nonlocked screws (NONLOCKED); bridge dynamization (BRIDGE) with 2 empty screw holes proximal to the fracture; screw dynamization with far cortical locking (FCL) screws; and plate dynamization with active locking plates (ACTIVE). Construct stiffness, axial motion, and shear motion at the fracture site were measured to characterize each dynamization methods. Results Compared with LOCKED control constructs, NONLOCKED constructs had a similar stiffness (P = 0.08), axial motion (P = 0.07), and shear motion (P = 0.97). BRIDGE constructs reduced stiffness by 45% compared with LOCKED constructs (P < 0.001), but interfragmentary motion was dominated by shear. Compared with LOCKED constructs, FCL and ACTIVE constructs reduced stiffness by 62% (P < 0.001) and 75% (P < 0.001), respectively, and significantly increased axial motion, but not shear motion. Conclusions In a surrogate model of a distal femur fracture, replacing locked with nonlocked diaphyseal screws does not significantly decrease construct stiffness and does not enhance interfragmentary motion. A longer bridge span primarily increases shear motion, not axial motion. The use of FCL screws or active plating delivers axial dynamization without introducing shear motion.
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Despite the fact that the calcaneus is the commonest tarsal bone fractured, many controversies exist in the literature regarding the management options. This stems from the fact that the understanding of the fracture pattern has evolved only recently, surgical approaches have lately been standardized, surgical timing has become more clear, and newer implants are regularly being introduced. Despite the significant advances, complications and controversies related to this common fracture abound. The present paper looks at all aspects of modern management options of calcaneus fractures and tries to review the literature with regard to the controversial issues that still persist.
Article
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Current methods of treating calcaneus fractures vary greatly, and many techniques of internal fixation have been described. The study of these fractures has been limited in part by the lack of a suitable laboratory model. In this study, a new cadaveric model of calcaneus fractures was developed, using a combination of osteotomies and impaction. The model allows a pattern of intraarticular injury to be reproduced consistently. The model was used to examine one aspect of internal fixation. It was hypothesized that fixation would be more stable if the screws supporting the posterior facet were incorporated into the lateral plate, as opposed to being separate from the plate. Six pairs of anatomic specimen legs were used, and each pair was divided randomly between two experimental groups. In Group A (screws out), the posterior facet screws were outside the plate, and in Group B (screws in), the screws were incorporated into the plate. The strength of the reconstructed calcanei were evaluated by axial loading of the limb through the tibia. Stiffness and energy to failure were significantly greater and Bohler's angle significantly less compromised in Group B. It was concluded that the position of the articular fragment of comminuted calcaneal fractures will be maintained at higher loads when the screws in the posterior facet are incorporated into the lateral plate. The model of calcaneal fractures described in this study may be suitable for examining other aspects of fixation.
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We present an in vitro biomechanical study performed to evaluate and compare, for an experimentally produced fracture of the calcaneum (Duparc grade IV), the reaction of 3 standard models of internal fixation commonly used in these fractures and which occupy different volumes. We compared different methods of fixation using fresh human calcanei. In two experimental series, we compared triangular internal fixation (3 1/4 tube AO plates Saragaglia), Y internal fixation (2 1/3 tube AO plates Bezes), isolated screw technique (three 3.5 diameter screws, two 4.5 diameter screws). The plates and screws were made of identical material (316L). Both series used 8 pairs of bone (talo-calcaneum system) with the same fracture submitted to a 200N to 1000N load. Stiffness and movement were analyzed using 8 references on the calcaneum. The stiffness and movement analysis with 8 references points demonstrated the superior resistance to bending with the triangular internal fixation. Fixation stability was significantly better than with the Y or screw technique. This study underlined the importance of triangular trabecular organization of cancellous bone on calcaneum biomechanics. We showed that the 3 (anterior, posterior and inferior) trabeculae must be repaired in calcaneum fractures to achieve horizontal and vertical stability of the talar joint. In our hands, restoration of the triangular architecture of calcaneum fractures, to resemble a roof truss, where the talus is fixed to the triangle vertex, is fundamental to obtain a rigid and stable internal fixation.
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We have assessed the long-term results after operative and non-operative treatment of undisplaced and displaced calcaneal fractures. At a mean of 6.5 years, we reviewed 70 patients with a calcaneal fracture who were divided into four groups: group 1, 18 patients with undisplaced fractures and a normal Böhler's angle (BA) who had been treated non-operatively; group 2, 23 with intra-articular fractures and a BA < 10 degrees who had been treated non-operatively; group 3, 13 with intra-articular fractures and a BA > 10 degrees who had been treated surgically; and group 4, 16 with intra-articular fractures and a BA < 10 degrees who had been treated surgically. The results were assessed by a clinical score considering pain, return to work, return to physical activity, change in shoe-wear and the requirement for subtalar arthrodesis. Patients with undisplaced calcaneal fractures had a good outcome. Those with displaced fractures treated surgically who presented at follow-up with a BA > 10 degrees had a satisfactory functional outcome and those with displaced fractures who had non-operative treatment had a poor outcome. The poorest outcome was consistently seen in patients who were treated operatively without restoration of BA. Open reduction and internal fixation of intra-articular calcaneal fractures can only be expected to benefit those patients in whom nearly anatomical reconstruction is obtained.
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Our study was undertaken to assess the inter- and intra-observer variability of the classification system of Sanders for calcaneal fractures. Five consultant orthopaedic surgeons with different subspecialty interests classified CT scans of 28 calcaneal fractures using this classification system. After six months, they reclassified the scans. Kappa statistics were used to analyse the two groups. The interobserver variability of the classification system was 0.32 (95% confidence interval (CI) 0.26 to 0.38). The subclasses were then combined and assessment of agreement between the general classes as a whole gave a kappa value of 0.33 (95% CI 0.25 to 0.41). The mean kappa value for intra-observer variability of the classification system was 0.42 (95% CI 0.22 to 0.62). When the subclasses were combined, it was 0.45 (95% CI 0.21 to 0.65). Our results show that, despite its popularity, the classification system of Sanders has only fair agreement among users.
Article
Most calcaneal fractures occur in male industrial workers, making the economic importance of this injury substantial. Many authors have reported that patients may be totally incapacitated for as long as three years and partially impaired for as long as five years after the injury1,11,39,73,94,133. Although modern operative intervention has improved the outcome in many patients, there still is no real consensus on classification, treatment, operative technique, or postoperative management. In this article, the current thinking regarding the treatment of these very difficult fractures will be reviewed. As early as 1908, Cotton and Wilson suggested that open reduction of a calcaneal fracture was contra-indicated27. McLaughlin agreed, likening attempts at operative fixation to the “nailing of a custard pie to the wall.”76 Cotton and Wilson recommended closed treatment with use of a medially placed sandbag, a laterally placed felt pad, and a hammer to reduce the lateral wall and “reimpact” the fracture27. Although initially they were enthusiastic about this technique, by the 1920s they had abandoned the treatment of acute fractures altogether and had turned instead to the treatment of healed malunions29. Despite the fact that Bohler11 advocated open reduction in 1931, the principal reasons for the predominance of nonoperative treatment were the technical problems associated with operative treatment. Anesthesia was not always effective, radiography and fluoroscopy were not well developed, antibiotics did not exist, and a sound understanding of the principles of internal fixation was lacking105. The resulting complications of infection, malunion, and nonunion, and the possible need for amputation, made most surgeons believe that treatment should be nonoperative. In 1935, Conn, who was dissatisfied with standard treatment methods, reported on the use of delayed primary triple arthrodesis, with …
Article
Screws placed into cancellous bone in orthopedic surgical applications, such as fixation of fractures of the femoral neck or the lumbar spine, can be subjected to high loads. Screw pullout is a possibility, especially if low density osteoporotic bone is encountered. The overall goal of this study was to determine how screw thread geometry, tapping, and cannulation affect the holding power of screws in cancellous bone and determine whether current designs achieve maximum purchase strength. Twelve types of commercially available cannulated and noncannulated cancellous bone screws were tested for pullout strength in rigid unicellular polyurethane foams of apparent densities and shear strengths within the range reported for human cancellous bone. The experimentally derived pullout strength was compared to a predicted shear failure force of the internal threads formed in the polyurethane foam. Screws embedded in porous materials pullout by shearing the internal threads in the porous material. Experimental pullout force was highly correlated to the predicted shear failure force (slope = 1.05, R2 = 0.947) demonstrating that it is controlled by the major diameter of the screw, the length of engagement of the thread, the shear strength of the material into which the screw is embedded, and a thread shape factor (TSF) which accounts for screw thread depth and pitch. The average TSF for cannulated screws was 17 percent lower than that of noncannulated cancellous screws, and the pullout force was correspondingly less. Increasing the TSF, a result of decreasing thread pitch or increasing thread depth, increases screw purchase strength in porous materials. Tapping was found to reduce pullout force by an average of 8 percent compared with nontapped holes (p = 0.0001). Tapping in porous materials decreases screw pullout strength because the removal of material by the tap enlarges hole volume by an average of 27 percent, in effect decreasing the depth and shear area of the internal threads in the porous material.
Article
We have assessed the long-term results after operative and non-operative treatment of undisplaced and displaced calcaneal fractures. At a mean of 6.5 years, we reviewed 70 patients with a calcaneal fracture who were divided into four groups: group 1, 18 patients with undisplaced fractures and a normal Böhler’s angle (BA) who had been treated non-operatively; group 2, 23 with intra-articular fractures and a BA <10° who had been treated non-operatively; group 3, 13 with intra-articular fractures and a BA >10° who had been treated surgically; and group 4, 16 with intra-articular fractures and a BA <10° who had been treated surgically. The results were assessed by a clinical score considering pain, return to work, return to physical activity, change in shoe-wear and the requirement for subtalar arthrodesis. Patients with undisplaced calcaneal fractures had a good outcome. Those with displaced fractures treated surgically who presented at follow-up with a BA >10° had a satisfactory functional outcome and those with displaced fractures who had non-operative treatment had a poor outcome. The poorest outcome was consistently seen in patients who were treated operatively without restoration of BA. Open reduction and internal fixation of intra-articular calcaneal fractures can only be expected to benefit those patients in whom nearly anatomical reconstruction is obtained.
Article
A MEDLINE search from 1980 through 1996 revealed 1845 articles dealing with calcaneal fractures. Six of these articles that compared operative versus nonoperative treatment for displaced calcaneal fractures met the minimum criteria for inclusion in a metaanalysis. A statistical summary of information across the six articles revealed a trend for surgically treated patients to be more likely to return to the same type of work as compared with nonoperatively treated individuals. There also was a trend for nonoperatively treated patients to have a higher risk of experiencing severe foot pain than did operatively treated patients. Unfortunately, none of the other outcomes could be summarized formally across studies using statistical techniques because of variability in reporting across studies. Although the tendency was always for operatively treated patients to have better outcomes (reaching statistical significance in some of the articles), the strength of evidence to recommend operative treatment for displaced intraarticular calcaneal fractures remains weak. A large prospective randomized controlled trial should be able to answer this question.
Article
The Herbert screw has been demonstrated to have widespread clinical applicability. A biomechanical and histological evaluation of the Herbert screw was conducted to better define its applications. When subjected to pull-out, toggle, and compression testing, in a cancellous bone calf model, it was demonstrated to be biomechanically inferior to the 4.0 mm ASIF cancellous screw. The use of two Herbert screws minimized but did not eliminate this difference. Articular cartilage healing in a rabbit model was consistently demonstrated if the Herbert screw was buried deep to the osteochondral junction. However, toluidine blue histochemical staining showed that the hyaline-like repair cartilage differed qualitatively from normal cartilage. Utilization of the Herbert screw should include an understanding of the limitations of its fixation potential and a recognition of the repair response after intraarticular applications.
Article
Displaced intra-articular fractures of the calcaneus remain a diagnostic and therapeutic dilemma. The classification of these fractures has been frustrated in the past by limitations of radiographic technique. Because of our need to consistently analyze our results, a CT scan classification was developed, based on the number and location of articular fracture fragments. The authors have treated displaced intra-articular calcaneal fractures according to an operative protocol using a modified lateral approach, a new plate and lag screws, all without the use of bone graft. This article will discuss in depth the treatment options available as well as the controversies that surround them.
Article
Forty-four patients who had had fifty-two calcaneal fractures were managed with open reduction and internal fixation. The results were reviewed retrospectively, between four and fourteen years after the operation, with use of an evaluation system for the hindfoot and with plain radiographs. The characteristics of the patients that were associated with an unsatisfactory outcome were an age of more than fifty years, a greater body weight, work involving strenuous labor, and increased time missed from work due to the injury. Other prognostic variables associated with an unsatisfactory result included subtalar incongruity, osteoarthrosis of the talonavicular joint and the ankle, an increased heel width, a decreased fibulocalcaneal space, and a decreased Böhler-angle ratio of the fractured to the normal side. The heel height, fat-pad height, arch angle, talocalcaneal angle, and length of the Achilles-tendon fulcrum were not related to the outcome. Patients who had had a tongue-type fracture had a better result than those who had had a central depression fracture, while those who had had a central depression fracture had a better outcome than those who had had a comminuted fracture. Comminution of tongue and large central-depression fractures was associated with a worse prognosis. The most common most painful area in the patients who had a satisfactory outcome was the lateral aspect of the hindfoot, while in those who had an unsatisfactory result, it was the heel pad.
Article
From January 1987 to September 1990, 132 displaced intraarticular calcaneal fractures were treated operatively using a lateral approach, lag screws, and side plate without bone graft. To evaluate the results, a classification for intraarticular calcaneal fractures was developed, based on standardized coronal and transverse computed tomography (CT) scans of both feet. Type 1 fractures were nondisplaced (and received nonoperative treatment); Type II were two-part or split fractures; Type III were three-part or split depression fractures; and Type IV were four-part or highly comminuted articular fractures. Results were evaluated using the Maryland Foot Score and repeat CT scans. One hundred twenty cases were available for a minimum of one year follow-up evaluation (range, 12-56 months; mean, 29.3 months). Roentgenographic evaluation of calcaneal body dimensions showed restoration of heel height (98%), width (110%), and length (100%) to virtually normal in all cases, regardless of preoperative displacement. Roentgenographically, articular reduction was anatomic in 68 of 79 (86%) Type II fractures, 18 of 30 (60%) Type III fractures, and 0 of 11 (0%) Type IV fractures. Excellent or good clinical results occurred in 58 of 79 (73%) Type II fractures, 21 of 30 (70%) Type III fractures, and one of 11 (9%) Type IV fractures. When excellent and good clinical results were compared by year, a distinct learning curve appeared (1987, 27%; 1988, 54%; 1989, 74%; 1990, 84%). Despite an improved outcome for Type II and III fractures with increasing surgical experience, the results of operative intervention in Type IV fractures were no better, even after four years.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Displaced intraarticular fractures of the calcaneus require operative intervention to restore the anatomy of the bone, which in turn is the requirement for recovery of subtalar joint mobility. Surgery through a lateral incision, without opening the sheath of the peroneal tendons, and the use of lag screws and a "Y-plate," must restore not only the respective positions of the "three poles" of the calcaneus but also the respective orientations of the articular surfaces. Stable internal fixation allows early active and passive mobilization of the subtalar and ankle joints. If this is not achieved, the functional outcome will be poor.
Article
Buy Article Permissions and Reprints Author summary Treatment of fractures of the calcaneus must take into consideration the fracture type and mechanism of injury. A population of patients from the period of 1941 to 1950 with calcaneal fractures is presented. Evaluations of subtalar joint involvement, conservative and surgical modes of treatment, and the influence of age were done with a focus on fractures into the posterior subtalaoid joint. If precise surgical reduction of the fractures and exact repositioning of the fragments is achieved, better results can be obtained than those found with conservative treatment, but if successful repositioning cannot be attained, conservative treatment with exercise presents a better alternative, particularly in an older population.
Article
Screws placed into cancellous bone in orthopedic surgical applications, such as fixation of fractures of the femoral neck or the lumbar spine, can be subjected to high loads. Screw pullout is a possibility, especially if low density osteoporotic bone is encountered. The overall goal of this study was to determine how screw thread geometry, tapping, and cannulation affect the holding power of screws in cancellous bone and determine whether current designs achieve maximum purchase strength. Twelve types of commercially available cannulated and noncannulated cancellous bone screws were tested for pullout strength in rigid unicellular polyurethane foams of apparent densities and shear strengths within the range reported for human cancellous bone. The experimentally derived pullout strength was compared to a predicted shear failure force of the internal threads formed in the polyurethane foam. Screws embedded in porous materials pullout by shearing the internal threads in the porous material. Experimental pullout force was highly correlated to the predicted shear failure force (slope = 1.05, R2 = 0.947) demonstrating that it is controlled by the major diameter of the screw, the length of engagement of the thread, the shear strength of the material into which the screw is embedded, and a thread shape factor (TSF) which accounts for screw thread depth and pitch. The average TSF for cannulated screws was 17 percent lower than that of noncannulated cancellous screws, and the pullout force was correspondingly less. Increasing the TSF, a result of decreasing thread pitch or increasing thread depth, increases screw purchase strength in porous materials. Tapping was found to reduce pullout force by an average of 8 percent compared with nontapped holes (p = 0.0001). Tapping in porous materials decreases screw pullout strength because the removal of material by the tap enlarges hole volume by an average of 27 percent, in effect decreasing the depth and shear area of the internal threads in the porous material.
Article
To evaluate and compare the mechanical stability of two different fixation techniques on experimentally induced calcaneus fractures. Thirteen fresh frozen cadaver lower limbs had intraarticular calcaneal fractures produced with an impact loading device. Internal fixation was then performed through lateral and medial approaches using 3.5-mm interfragmentary screws fixed to the posterior facet. Next, either a five-hole 1/3 tubular or five-hole reconstruction plate was placed on the lateral cortex. Radiographs were obtained to confirm reduction. The foot was then cyclically loaded for 500 cycles with a compressive load of 98 N, followed by loading to failure. The displacement at the posterior facet fracture line between the loaded and unloaded foot at the 500th cycle was 0.30 +/- 0.08 mm and 0.39 +/- 0.18 mm for the tubular and reconstruction plates, respectively. These displacements were not statistically significant (Student's t test p > 0.3). The load and displacement at failure for the tubular plate were 2021 +/- 1050 N and 6.10 +/- 1.75 mm, respectively. Those for the reconstruction plate were 1923 +/- 697 N and 4.57 +/- 1.32 mm (p > 0.09). This study supports the mechanical viability of using less prominent plates for the fixation of intra-articular calcaneal fractures.
Article
A MEDLINE search from 1980 through 1996 revealed 1845 articles dealing with calcaneal fractures. Six of these articles that compared operative versus nonoperative treatment for displaced calcaneal fractures met the minimum criteria for inclusion in a meta-analysis. A statistical summary of information across the six articles revealed a trend for surgically treated patients to be more likely to return to the same type of work as compared with nonoperatively treated individuals. There also was a trend for nonoperatively treated patients to have a higher risk of experiencing severe foot pain than did operatively treated patients. Unfortunately, none of the other outcomes could be summarized formally across studies using statistical techniques because of variability in reporting across studies. Although the tendency was always for operatively treated patients to have better outcomes (reaching statistical significance in some of the articles), the strength of evidence to recommend operative treatment for displaced intraarticular calcaneal fractures remains weak. A large prospective randomized controlled trial should be able to answer this question.
Article
To The Editor: We congratulate Dr. Sanders on his excellent Current Concepts Review “Displaced Intra-Articular Fractures of the Calcaneus” (82-A: 225-50, Feb. 2000). Since this topic is of paramount interest and is still a matter of some debate, we would like to provide some information from the non-English-language literature. The historical review should mention the pioneering work of the French school in the 1920s, above all Leriche, who, dissatisfied with the results of closed treatment of calcaneal fractures, practiced open reduction and internal fixation with staples and screws1. The method of percutaneous leverage of the displaced tuberosity fragment and subsequent plaster immobilization of the pin was introduced as early as 1934 by the German surgeon Westhues2. We are well aware that the difficulties in the management of calcaneal fractures are reflected by a long historical record of different treatment options. However, the two above-mentioned procedures represent “milestones” that influenced and inspired surgeons like Palmer and Essex-Lopresti, who established the principles of modern treatment of calcaneal fractures. The computed-tomography-based classification by Zwipp and colleagues3, which was cited by Dr. Sanders, has proved to be of prognostic value when supplemented by an evaluation of soft-tissue damage and comminution on a 12-point scale. Bone fragments (maximum, five) and affected joint facets (maximum, three) are credited with 1 point each. Open or closed soft-tissue damage is scored on a 3-point scale. An additional point is assigned in case of extensive comminution of one major bone fragment or a fracture of another tarsal bone. With a predictive value of 86%, an excellent result can be expected with less than 7 points; a good result, with 7 or 8 points; a satisfactory result, with 9 to 10 points; and a poor result, with 11 or 12 points4. These …
Article
Open reduction and internal fixation is the treatment of choice for displaced intra-articular calcaneal fractures at many orthopaedic trauma centers. The purpose of this study was to determine whether open reduction and internal fixation of displaced intra-articular calcaneal fractures results in better general and disease-specific health outcomes at two years after the injury compared with those after nonoperative management. Patients at four trauma centers were randomized to operative or nonoperative care. A standard protocol, involving a lateral approach and rigid internal fixation, was used for operative care. Nonoperative treatment involved no attempt at closed reduction, and the patients were treated only with ice, elevation, and rest. All fractures were classified, and the quality of the reduction was measured. Validated outcome measures included the Short Form-36 (SF-36, a general health survey) and a visual analog scale (a disease-specific scale). Between April 1991 and December 1997, 512 patients with a calcaneal fracture were treated. Of those patients, 424 with 471 displaced intra-articular calcaneal fractures were enrolled in the study. Three hundred and nine patients (73%) were followed and assessed for a minimum of two years and a maximum of eight years of follow-up. The outcomes after nonoperative treatment were not found to be different from those after operative treatment; the score on the SF-36 was 64.7 and 68.7, respectively (p = 0.13), and the score on the visual analog scale was 64.3 and 68.6, respectively (p = 0.12). However, the patients who were not receiving Workers' Compensation and were managed operatively had significantly higher satisfaction scores (p = 0.001). Women who were managed operatively scored significantly higher on the SF-36 than did women who were managed nonoperatively (p = 0.015). Patients who were not receiving Workers' Compensation and were younger (less than twenty-nine years old), had a moderately lower Böhler angle (0 degrees to 14 degrees ), a comminuted fracture, a light workload, or an anatomic reduction or a step-off of < or =2 mm after surgical reduction (p = 0.04) scored significantly higher on the scoring scales after surgery compared with those who were treated nonoperatively. Without stratification of the groups, the functional results after nonoperative care of displaced intra-articular calcaneal fractures were equivalent to those after operative care. However, after unmasking the data by removal of the patients who were receiving Workers' Compensation, the outcomes were significantly better in some groups of surgically treated patients.
Article
The Locking Compression Plate (LCP), in combination with the LISS and the PHILOS, is part of a new plate generation requiring an adapted surgical technique and new thinking about commonly used concepts of internal fixation using plates. The following guidelines are needed to avoid failures and possible complications in the hands of surgeons not yet confident with the new implant philosophy. The importance of the reduction technique and minimal-invasive plate insertion and fixation is addressed to keep bone viability undisturbed. Understanding of mechanical background for choosing the proper implant length and the type and number of screws is essential to obtain a sound fixation with a high plate span ratio and a low plate screw density. A high plate span ration decreases the load onto the plate. A high working length of the plate in turn reduces the screw loading, thus fewer screws need to be inserted and the plate screw density can be kept low. Knowledge of the working length of the screw is helpful for the proper choice of monocortical or bicortical screws. Selection is done according to the quality of the bone structure and is important to avoid problems at the screw thread bone interface with potential pullout of screws and secondary displacement. Conclusive rules are given at the end of this chapter.
Article
The basic principles of an internal fixation procedure using a conventional plate and screw system (compression method) are direct, anatomical reduction and stable internal fixation of the fracture. Wide exposure of the bone is usually necessary to gain access to and provide good visibility of the fracture zone to allow reduction and plate fixation to be performed. This procedure requires pre-contouring of the plate to match the anatomy of the bone. The screws are tightened to fix the plate onto the bone, which then compresses the plate onto the bone. The actual stability results from the friction between the plate and the bone. Anatomical reduction of the fracture was the goal of conventional plating technique, but over time a technique for bridging plate osteosynthesis has been developed for multifragmentary shaft fractures that, thanks to a reduction of vascular damage to the bone, permits healing with callus formation, as seen after locked nailing. Since the damage to the soft tissues and the blood supply is less extensive, more rapid fracture healing can be achieved. The newly developed, so-called locked internal fixators (e.g.PC-Fix and Less Invasive Stabilization System (LISS)), consist of plate and screw systems where the screws are locked in the plate. This locking minimizes the compressive forces exerted by the plate on the bone. This method of screw-plate fixation means that the plate does not need to touch the bone at all, which is of particular advantage in so-called Minimal Invasive Percutaneous Osteosynthesis (MIPO). Precise anatomical contouring of a plate is no longer necessary thanks to these new screws and because the plate does not need to be pressed on to the bone to achieve stability. This prevents primary dislocation of the fracture caused by inexact contouring of a plate. The LISS plates are precontoured to match the average anatomical form of the relevant site and, therefore, do not have to be further adapted intraoperatively. The development of the locked internal fixator method has been based on scientific insights into bone biology especially with reference to its blood supply. The basic locked internal fixation technique aims at flexible elastic fixation to initiate spontaneous healing, including its induction of callus formation. This technology supports what is currently known as MIPO. The development of the Locking Compression Plate (LCP) has only been possible based on the experience gained with the PC-Fix and LISS. With reference to the mechanical, biomechanical and clinical results, the new AO LCP with combination holes can be used, depending on the fracture situation, as a compression plate, a locked internal fixator, or as an internal fixation system combining both techniques. The LCP with combination holes can also be used, depending on the fracture situation, in either a conventional technique (compression principle), bridging technique (internal fixator principle), or a combination technique (compression and bridging principles). A combination of both screw types offers the possibility to achieve a synergy of both internal fixation, methods. If the LCP is applied as a compression plate, the operative technique is much the same as conventional technique, in which existing instruments and screws can be used. The internal fixator method can be applied through an open but less invasive or an MIPO approach. An indirect closed reduction is necessary when using the LCP in the internal fixator method bridging the fracture zone. A combination of both plating techniques is possible and valuable, depending on the indication. It is important to command a knowledge of both techniques and their different features.
Article
New plating techniques, such as non-contact plates, have been introduced in acknowledgment of the importance of biological factors in internal fixation. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability, e.g. fracture motion, and the risk of implant failure can best be controlled. The results of a study based on in vitro experiments with composite bone cylinders and finite element analysis using the Locking Compression Plate (LCP) for diaphyseal fractures are presented and recommendations for clinical practice are given. Several factors were shown to influence stability both in compression and torsion. Axial stiffness and torsional rigidity was mainly influenced by the working length, e.g. the distance of the first screw to the fracture site. By omitting one screw hole on either side of the fracture, the construct became almost twice as flexible in both compression and torsion. The number of screws also significantly affected the stability, however, more than three screws per fragment did little to increase axial stiffness; nor did four screws increase torsional rigidity. The position of the third screw in the fragment significantly affected axial stiffness, but not torsional rigidity. The closer an additional screw is positioned towards the fracture gap, the stiffer the construct becomes under compression. The rigidity under torsional load was determined by the number of screws only. Another factor affecting construct stability was the distance of the plate to the bone. Increasing this distance resulted in decreased construct stability. Finally, a shorter plate with an equal number of screws caused a reduction in axial stiffness but not in torsional rigidity. Static compression tests showed that increasing the working length, e.g. omitting the screws immediately adjacent to the fracture on both sides, significantly diminished the load causing plastic deformation of the plate. If bone contact was not present at the fracture site due to comminution, a greater working length also led to earlier failure in dynamic loading tests. For simple fractures with a small fracture gap and bone contact under dynamic load, the number of cycles until failure was greater than one million for all tested constructs. Plate failures invariably occurred through the DCP hole where the highest von Mises stresses were found in the finite element analysis (FEA). This stress was reduced in constructions with bone contact by increasing the bridging length. On the other hand, additional screws increased the implant stress since higher loads were needed to achieve bone contact. Based on the present results, the following clinical recommendations can be made for the locked internal fixator in bridging technique as part of a minimally invasive percutaneous osteosynthesis (MIPO): for fractures of the lower extremity, two or three screws on either side of the fracture should be sufficient. For fractures of the humerus or forearm, three to four screws on either side should be used as rotational forces predominate in these bones. In simple fractures with a small interfragmentary gap, one or two holes should be omitted on each side of the fracture to initiate spontaneous fracture healing, including the generation of callus formations. In fractures with a large fracture gap such as comminuted fractures, we advise placement of the innermost screws as close as practicable to the fracture. Furthermore, the distance between the plate and the bone ought to be kept small and long plates should be used to provide sufficient axial stiffness.
Article
The management of calcaneus fractures and their associated soft tissue injuries are challenging tasks for the surgeon. Open reduction and stable internal fixation with a lateral plate and without joint transfixation has been established as a standard therapy for displaced intra-articular fractures with good to excellent results in two-thirds to three-quarters of cases in larger clinical series. Bone grafting appears not useful in the vast majority of cases. Anatomical reduction of joint congruity and the overall shape of the calcaneus are important prognostic factors. The quality of joint reduction should be reliably proven intra-operatively either with Brodén views, high-resolution fluoroscopy or open subtalar arthroscopy. Treatment results are adversely affected by open fractures, delayed reduction after more than 14 days and individual risk factors such as high body mass index and smoking. The extended lateral approach respects the neurovascular supply to the heel and allows a good exposure of the fractured lateral wall, and the subtalar and calcaneocuboid joints in most fractures. In selected fracture patterns percutaneous screw fixation, possibly with arthroscopic control, is a good alternative. Open fractures, compartment syndrome and fractures with severe soft tissue compromise are treated as emergency cases. Early, stable soft tissue coverage appears promising in treating complex open fractures. The benefits of newly developed plate designs and subtalar arthrolysis at the time of hardware removal remains to be proven in further studies. Calcaneal malunions after conservative therapy of displaced fractures are disabling conditions that can be treated successfully with a staged protocol according to the type of deformity. Treatment options include lateral wall decompression, subtalar in situ, or corrective, arthrodesis and calcaneal osteotomy along the former fracture line.
Article
Poor bone quality increases the technical difficulty and complications of operative treatment of nonunions and delayed unions of the diaphyseal humerus in older patients. Plates with screws that lock to the plate (transforming each screw into a fixed blade) are intended to improve the fixation of poor quality bone. Twenty-four patients (20 women, four men) with an average age of 72 years (range, 52-86 years) were followed up for a minimum of 12 months after locking compression plate fixation of an osteopenic delayed union (nine patients) or nonunion (15 patients) of the diaphyseal humerus. Twelve patients had iliac crest cancellous bone grafts, two patients had local graft, and 13 patients had demineralized bone applied to the fracture site. All the fractures eventually healed; two healed after a second procedure for autogenous bone grafting in patients who initially received demineralized bone. Using a modification of the Constant and Murley shoulder score, the results were good or excellent in 22 patients, and fair in two patients. Locking compression plates provide stable fixation of poor quality bone in patients with delayed union or nonunion of the humerus. Successful union and restoration of function are achieved in most patients. We no longer consider osteoporosis a contraindication to operative fixation of an ununited fracture of the humeral diaphysis.
Article
Although pioneers such as Leriche in 1921 [5] and Judet et al in 1954 [4] introduced screw or plate fixation of the broken calcaneus, surgical treatment using open anatomical reduction and stable internal osteosynthesis only commenced at the start of the 1980s. This treatment was made possible by the introduction of new imaging methods such as CT which allowed better detection of the fracture pathology and provided the basis for new surgical strategies. Since the start of the 1990s, various anatomically shaped steel and titanium calcaneal plates have been available. The Foot and Ankle Expert Group of the AO Foundation together with Synthes USA developed an anatomically shaped interlocking calcaneal plate, which has been available in steel since 2002, and a titaniummolybdenum(15%) alloy version (Mathys) since November 2003. The latter is now being tested clinically in our unit.
Article
This study compared the outcomes of displaced intraarticular calcaneal fractures in women treated operatively or nonoperatively. This was part of a prospective, randomized, controlled, multi-center, clinical trial performed at four level I trauma hospitals. In addition, we compared the long-term outcomes in women with those reported in men in an earlier study. Forty-one women (43 fractures) required treatment for displaced intraarticular calcaneal fractures. Patients' ages ranged from 17 to 65 years at the time of injury. All fractures were closed injuries and had posterior facet displacement of more than 2 mm. Patients were randomly assigned to either the nonoperatively or operatively treated groups. Nonoperative treatment included ice and elevation, while operative treatment consisted of open reduction and internal fixation using a standard lateral approach. Outcomes were measured using the validated Short Form-36 Health Survey (SF-36) and the Visual Analogue Scale (VAS). Women were 3.18 times (RR 3.18, 95% CI 1.03- 9.79) more likely to report high SF-36 scores after operative treatment than those who received nonoperative treatment. Operative outcomes in women were better than those reported in an earlier study in men (SF-36: 77.47 in women compared to 67.56 in men, p = .07; VAS: 81.47 in women compared to 67.04 in men, p = .01). In women the fractures generally were caused by low-energy trauma that produced less severe injuries (higher Bohler angles). Most patients were not receiving Workman's Compensation benefits and did light to moderate work. Operative treatment of the fractures showed statistically significant better results when compared to nonoperative treatment (SF-36: p = .04; VAS: p = .10) in women. Displaced intraarticular calcaneal fractures in women should be treated by open reduction and internal fixation through a lateral approach.
Article
Restoration of painless and satisfactory elbow function after a fracture of the distal humerus requires anatomic reconstruction of the articular surface, restitution of the overall geometry of the distal humerus, and stable fixation of the fracture fragments to allow early and full rehabilitation. Although these goals are now widely accepted by the orthopaedic community, they may be technically difficult to achieve, especially in the presence of substantial osteoporosis or comminution. Failure, when it occurs, typically occurs at the supracondylar level through loss of fixation in the distal fragments. To prevent such failure and thereby maximize the potential for union and full elbow mobility after a severely fractured distal humerus, 2 principles must be satisfied: (1) fixation in the distal fragment must be maximized and (2) all fixation in distal fragments should contribute to stability between the distal fragments and the shaft. There are 8 technical objectives by which these principles are met: (1) every screw in the distal fragments should pass through a plate; (2) engage a fragment on the opposite side that is also fixed to a plate; (3) as many screws as possible should be placed in the distal fragments; (4) each screw should be as long as possible; (5) each screw should engage as many articular fragments as possible; (6) the screws in the distal fragments should lock together by interdigitation, creating a fixed-angle structure; (7) plates should be applied such that compression is achieved at the supracondylar level for both columns; and (8) the plates must be strong enough and stiff enough to resist breaking or bending before union occurs at the supracondylar level. These can be achieved with parallel plating. Severe metaphyseal comminution and bone loss are managed by supracondylar shortening. From the biomechanical data in the literature, 3 conclusions can be reached concerning fixation of distal humeral fractures. First, the concept that plates need to be placed perpendicular (90 degrees /90 degrees orientation) is unsubstantiated and incorrect. Second, parallel placement of 2 plates in the sagittal plane is as strong or stronger than the 90 degrees /90 degrees orientation. Finally, linking the plates together through the bone, thereby creating the architectural equivalent of an arch, offers the greatest biomechanical stability for comminuted distal humeral fractures. This can be done by interdigitating and locking the screws together as they pass through the distal fragments from the medial and lateral plates placed in the sagittal plane.
Article
We compared different plates in an experimental calcaneal fracture model under biocompatible loading. Four plates were tested: a plate without locked screws (Synthes), and three different plates with locked screws (Newdeal, Darco, Synthes). Synthetic calcanei (Sawbone) were osteotomized to create a fracture model, and the plates were fixed onto them. Seven specimens for each plate model were subjected to cyclic loading (preload 20 N, 1,000 cycles with 800 N, 0.75 mm/s), and load to failure (0.75 mm/s). Motion, forces, plastic deformation of the plate, and consequent depression of the posterior joint facet were analyzed. During cyclic loading, all plates with locked screws showed statistically significant lower displacement in the primary loading direction than the plates without locked screws. Mean values (mm) of maximal displacements for each plate during cyclic loading were as follows: Synthes, 3.5; Darco, 4.5; Newdeal, 5.0; Synthes without locked screws, 7.5; (p < 0.001). No statistically significant differences between the plates were found in relation to loads to failure and corresponding displacement. This is the first biomechanical study to assess the stability of different plates currently in use in our practice for the fixation of calcaneal fractures. Our results showed that plates with locked screws provided greater stability during cyclic loading than the plate without locked screws.
Article
Operative intervention is an accepted treatment for fractures of the calcaneus. However, the literature discourages surgery for these fractures in the elderly. The purpose of this paper was to review the outcomes of surgical treatment of displaced fractures of the calcaneus in elderly patients. Between November 1987 and June 2000, forty-two patients (forty-four fractures) who were sixty-five years of age or older underwent surgery for a calcaneal fracture. The mechanism of injury, fracture pattern, and medical comorbidities were recorded. Thirty-five patients with a total of thirty-seven fractures were available for follow-up, which was conducted with physical and radiographic examinations and outcomes assessment with the Short Form-36 (SF-36), the American Orthopaedic Foot and Ankle Society ankle-hindfoot scale, and the Short Musculoskeletal Function Assessment survey. The minimum duration of follow-up was two years, and the average duration was forty-four months. All but one fracture (97% of the fractures) healed at an average of 110 days. The average active range of motion was 38 degrees of plantar flexion, 10 degrees of dorsiflexion, 16 degrees of inversion, and 11 degrees of eversion. The average American Orthopaedic Foot and Ankle Society score was 82.4 points, the average SF-36 score was 52.8 points, and the average Short Musculoskeletal Function Assessment score was 20.4 points. Posttraumatic subtalar arthritis developed in twelve patients. There were twelve minor complications and four major complications (three cases of osteomyelitis and one nonunion), all of which were treated successfully. Open reduction appears to be an acceptable method of treatment for displaced calcaneal fractures in elderly patients. Careful patient selection is necessary because individuals presenting with severe osteopenia, those who are unable to walk or are able to walk only about the house, and those with a medical condition that precludes surgery may be better candidates for nonoperative care.
Article
The purpose of this cadaveric study was to compare the mechanical behavior of a locked compression plate, which uses threaded screw heads to create a fixed angle construct, with a dynamic compression plate construct in a cadaver radius model. Mechanical study with cyclic testing and high-speed optical motion analysis. Biomechanics laboratory at an academic institution. Eighteen pairs of fresh-frozen human cadaver radii were divided into 3 groups of 6 to be tested as a group in each of the following force applications: anteroposterior (AP) bending, mediolateral bending, or torsion. Each bone was osteotomized leaving a 5-mm fracture gap and then fixed with a plate. For each pair, 1 radius received a standard plate (limited-contact dynamic compression plates; LC-DCP), the contralateral radius was fixed with a locking compression plate (LCP), and specimens underwent cyclic loading. Normalized stiffness, average energy absorbed, and Newton-cycles to failure were calculated. In addition, a 3-dimensional, high-speed, infrared motion analysis system was used to evaluate motion at the fracture site. Construct stiffness, fracture site motion, cycles to failure, and energy absorption. Repeated measures ANOVA were used to detect differences between groups with time. In the torsion group, LCP specimens failed at 60% greater Newton-cycles than the LC-DCP (1473 vs. 918; P < 0.05). In the AP group, the LC-DCP absorbed significantly greater energy during 10,000 cycles compared with the LCP group (P < 0.05). The 2 constructs demonstrated different biomechanical behavior with time. As cycling progressed in the LC-DCP specimens under torsion testing, stiffness (measured at the actuator at the bone ends) did not change significantly; however, fracture motion (measured at the fracture surfaces) decreased significantly (P = 0.04). The LCP specimens did not display similar behavior. Our findings indicated that LCP constructs may demonstrate subtle mechanical superiority compared with the LC-DCP. The LCP specimens had less energy absorption in the AP group and survived longer in the torsion group. Discordance of motion between measurement regions was observed only in the LC-DCP torsion group, and may have been caused by plate-bone slippage or bone-screw subcatastrophic failure. However, many other compared parameters were found to be similar, and the clinical significance of the few differences found between constructs mandates further investigation.
Article
Critical analysis of the medium-term results of open reduction and internal fixation (ORIF) of displaced intra-articular calcaneus fractures with a standardized protocol in a greater patient cohort. From October 1993 to December 1999 314 patients (mean age 42.3 years) with 348 calcaneus fractures were seen at the Dresden University Hospital. 41 fractures were open, 4 with 1st degree, 28 with 2nd and 9 with 3rd degree soft tissue damage. 275 displaced intra-articular fractures were treated with ORIF, 262 (95.3 %) with plate osteosynthesis via an extended lateral approach. 169 patients could be evaluated at a mean of 18 months (range 10-47 months) postoperatively with an extended protocol of questionnaire, physical and radiographic examination. The Maryland Foot Score after 18 months follow-up averaged 80.8/100, the mean Zwipp score averaged 146.4/200. The functional result with the Merle d'Aubigné score was judged good to excellent in 86% of cases. Rates of deep infection and superficial wound edge necrosis increased significantly with open fractures and delay in surgery of more than 2 weeks after injury in closed fractures. Clinical results were adversely affected by even minor residual steps in the posterior facet (1-2 mm) as judged by CT or Brodén views (p < 0.001). Böhler's tuberosity-joint-angle had an impact on the final result when falling short compared to the unaffected contralateral side by more than 30% (p < 0.001). Management of intra-articular calcaneus fractures with a standardized protocol of ORIF and early mobilization leads to reproducible good or excellent clinical results in a majority of patients. New approaches like an interlocking calcaneus plate, the use of subtalar arthroscopy, early soft tissue coverage for complex open injuries and percutaneous screw fixation for selected fractures should further improve prognosis.
The Foot and its Disorders
  • W C Hutton
  • J R Stott
  • I A Stokes
Hutton, W.C., Stott, J.R., Stokes, I.A., 1982. The Foot and its Disorders. Blackwell Scientific, Oxford, England.
Comparative biomechanical study of 3 types of osteosynthesis of the Duparc grade IV fractures of the calcaneus: value of triangular internal fixation
  • Badet