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ABSTRACT: Although the mouse has become a preferred species for molecular studies on fracture healing, gait analysis after fracture fixation and during bone healing has not yet been performed in mice. Herein, we introduce a novel technique for gait analysis in mice and report the change of motion pattern after fracture and fixation. A standardized femur fracture was stabilized by a common pin. The non-fractured tibia was additionally marked with a pin, allowing continuous analysis of the tibio-femoral angle by digital video-radiography. Dynamic gait analysis was performed at day fourteen after surgery in a radio-opaque running wheel. Fracture fixation resulted in a significantly reduced range and maximum of the tibio-femoral angle compared to non-fractured controls. This was associated with a significantly reduced stride length. Because stride frequency was slightly increased and, thus, stride time diminished, stride velocity was not significantly reduced compared to controls. Thus, our study demonstrates distinct alterations of the gait of mice at 2 weeks after femur fracture and stabilization. Our results support the need of gait analysis in fracture healing studies to assess the animals' well-being.
Journal of biomechanics 12/2010; 43(16):3240-3. · 2.66 Impact Factor
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ABSTRACT: Due to the great availability of specific antibodies, gene-targeted animals and knockout strains, mouse models came into the focus of musculoskeletal research. Herein, we introduce a calvarian defect model in mice that allows the repetitive analysis of blood vessel formation during bone repair by intravital microscopy.
The right parietal calvaria of 20 adult CD-1 mice were exposed by skin excision. Under continuous irrigation, a circular defect (Ø0.75 mm) was drilled into the calvarium without penetrating the inner cortical shell. A circular glass (Ø12 mm; thickness 0.15 mm) was fixed by two microscrews (M1; length 2mm) to cover the bone defect. Angiogenesis was analysed by intravital microscopy at days 0, 3, 6, 9, 12, 15, 18 and 21. In addition, bone repair was evaluated by histomorphometry at days 3, 6, 9 and 15. Immunohistochemical stainings for the angiogenic growth factor vascular endothelial growth factor (VEGF) and the cell proliferation marker proliferating cell nuclear antigen (PCNA) were performed to assess angiogenic and proliferative activity during healing of the calvarian defect.
Histomorphometry showed a typical pattern of intramembranous bone repair. Osseous bridging of the defect was observed at day 9. This was associated with the formation of a neo-periosteum, which covered the new woven bone and contained a dense network of newly formed blood vessels. At day 9, particularly cells of the neo-periosteum showed intense staining for VEGF, whilst PCNA-positive staining was found mainly in osteoblasts. At day 15, the major fraction of fibrous tissue was replaced by bone undergoing extensive remodelling. Intravital microscopy revealed an increase of vascular density between days 3 and 15. Blood vessel diameters showed an increase between days 3 and 9 and a subsequent decrease between days 9 and 21.
The present calvarian defect model provides a powerful tool to evaluate the process of angiogenesis during intramembranous bone repair in mice.
Injury 12/2010; 42(8):765-71. · 1.98 Impact Factor
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J H Holstein,
M Herrmann,
J Schmalenbach,
R Obeid,
I Olkü,
M Klein,
P Garcia,
T Histing, T Pohlemann,
M D Menger,
W Herrmann,
L Claes
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ABSTRACT: Recently, hyperhomocysteinemia has been shown to be associated with impaired fracture healing in mice. The main causes for hyperhomocysteinemia are deficiencies of folate and vitamin B12. However, there is no information on whether deficiencies of these B vitamins are affecting bone repair, too.
We used two groups of mice to investigate the impact of folate and vitamin B12 deficiency on fracture healing: mice of the first group were fed a folate- and vitamin B12-deficient diet (n=14), while mice of the second group received an equicaloric control diet (n=13). Four weeks after stabilizing a closed femur fracture, bone repair was analyzed by histomorphometry and biomechanical testing. In addition, serum concentrations of homocysteine, folate, vitamin B12, the bone formation marker osteocalcin (OC), and the bone resorption marker collagen I C-terminal crosslaps (CTX) were measured.
Serum analyses revealed significantly decreased concentrations of folate and vitamin B12 in animals fed the folate- and vitamin B12-deficient diet when compared to controls. This was associated with a moderate hyperhomocysteinemia in folate- and vitamin B12-deficient mice, while no hyperhomocysteinemia was found in controls. Three-point bending tests showed no significant differences in callus stiffness between bones of folate- and vitamin B12-deficient animals and those of control animals. In accordance, the histomorphometric analysis demonstrated a comparable size and tissue composition of the callus, and also serum markers of bone turnover did not differ significantly between the two groups.
We conclude that folate and vitamin B12 deficiency does not affect bone repair in mice.
Bone 07/2010; 47(1):151-5. · 4.02 Impact Factor
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ABSTRACT: Whereas pelvic injuries in patients in their 20s and 30s are typically caused by high energy trauma, another group suffering this injury are elderly patients between the seventh and eighth decades of life. Due to osteoporosis and co-morbidities females are particularly affected by low energy trauma. After examining the medical history a physical examination of the pelvis is performed. This is followed by imaging with X-ray and CT scanning with 3D reconstruction if necessary. If there are concomitant injuries additional diagnostics are essential (e.g. sonography, MRI, retrograde ureterography, cystography and excretion urogram). The standard AO/ATO classification (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association) has been well proven and does not depend on the age of the patient. Three different fracture types are differentiated, types A, B and C. This classification in combination with the description of the affected anatomical region (e.g. transsymphysis, transpubic, etc.) is sufficient in the daily clinical practice to decide on the necessary treatment. Often there are diagnostic difficulties in elderly patients (so-called differentiation of the A-B problem). In these patients a type A fracture is initially diagnosed and treated conservatively but due to persistent pain the imaging is repeated and an additional (insufficiency) fracture is found. With this new information the therapeutic regime has to be changed. The reconstruction of the pelvic ring is of major importance especially for elderly patients. This reduces the pain and the primary objective, an earliest possible rehabilitation without prolonged immobilization, can be achieved. In elderly patients external fixation with supra-acetabular screw positioning is an effective procedure and secondary insufficiency-instability (mostly dorsal) can be avoided. Whereas type A fractures can almost exclusively be treated non-surgically, types B and C fractures usually need surgery. As in young patients type B fractures are stabilized ventrally and C fractures dorsoventrally. In an emergency supra-acetabular external fixation and when required extraperitoneal tamponade has been established as the standard treatment for elderly patients in Germany. For the definitive surgical management standard procedures are used, but they often have to be modified depending on the bone structure.
Der Unfallchirurg 04/2010; 113(4):258-71. · 0.61 Impact Factor
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ABSTRACT: The tremendous increase of acetabular fractures in the elderly provides new challenges for their surgical treatment. The aim of this study was to evaluate the biomechanical properties of conventional and newly developed implants for the stabilisation of an anterior column combined with posterior hemitransverse fracture (ACPHTF), which represents the typical acetabular fracture in the elderly.
Using a single-leg stance model we analysed four different implant systems for the stabilisation of ACPHTFs in synthetic and cadaveric pelvises. Applying an increasing axial load, fracture dislocation was analysed with a new multidirectional ultrasonic measuring system. Results of the different implant systems were compared by Scheffé post hoc test and one-way ANOVA.
In synthetic pelvises, the standard reconstruction plate fixed by 3 periarticular long screws and a new titanium fixator with multidirectional interlocking screws were associated with significantly less dislocation of the fractured quadrilateral plate of the acetabulum when compared to a standard reconstruction plate fixed by only one periarticular long screw and a locking reconstruction plate. No significant differences between the different osteosynthesis techniques could be observed in cadaver pelvises, probably due to a heterogeneous bone quality.
We conclude that the plate fixation by positioning of periarticular long screws as well as the multidirectional positioning of interlocking screws account for the most sufficient fracture stabilisation of ACPHTFs under experimental conditions.
Injury 04/2010; 41(4):405-10. · 1.98 Impact Factor
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ABSTRACT: The definition of complex pelvic trauma has allowed a selection of those pelvic fracture patients with the highest mortality rate. The term complex pelvic trauma is used as a definition for pelvic fractures which are associated with serious soft tissue lesions in the pelvic region. These may include visceral and neurovascular, as well as extensive skin and muscle injuries. Haemodynamic instability particularly related to vascular injuries raises the mortality dramatically. Traumatic hemipelvectomy, which represents the worst case of a complex pelvic trauma, is associated with mortality rates of up to 60%. The pelvic study groups 1-3 of the German trauma association (DGU) and the Association for Osteosynthesis (AO) provide the worldwide largest database on pelvic injuries (group 1, 1991-1993: 1,722 patients from 10 hospitals; group 2, 1998-2002: 2,569 patients from 22 hospitals; and group 3, 2005-2007: 2,704 patients from 23 hospitals). Using this database this article reviews epidemiological data, therapy concepts, associated injuries as well as the incidence and mortality rates related to complex pelvic trauma over a 16-year time period. Special attention has been paid to complex trauma in the elderly (patients >60 years of age). An additional aim of this article is to analyze the correlation between different treatment modalities and the mortality rate of complex pelvic trauma and to investigate whether changes in the treatment of complex pelvic trauma have improved the outcome of these injuries. Taken together an increase in measures for an initial mechanical stabilization of the pelvic ring, such as the use of the pelvic C clamp, the external fixator or primary osteosynthesis was found over the 16-year observation period. In addition to stabilization of the pelvic ring, pelvic tamponade for mechanical haemostasis has been proven to be one of the most effective measures to control haemorrhaging. These treatment regimes did not differ between young patients and patients >60 years of age. Regarding the outcome of these treatment strategies only slight decreases in the mortality rate were found (pelvic study group 1: 21%; pelvic study group 2: 22%; pelvic study group 3: 18%). In all pelvic study groups the mortality rate in patients >60 years of age was found to be significantly higher than in individuals <60 years of age (pelvic study group 1: 57% versus 29.6%, pelvic study group 2: 33% versus 22.6%, pelvic study group 3: 41% versus 10.4%, p <0.05, respectively).
Der Unfallchirurg 03/2010; 113(4):281-6. · 0.61 Impact Factor
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ABSTRACT: The renin-angiotensin system (RAS) regulates blood pressure and electrolyte homeostasis. In addition, 'local' tissue-specific RAS have been identified, regulating regeneration, cell growth, apoptosis, inflammation and angiogenesis. Although components of the RAS are expressed in osteoblasts and osteoclasts, a local RAS in bone has not yet been described and there is no information on whether the RAS is involved in fracture healing. Therefore, we studied the expression and function of the key RAS component, angiotensin-converting enzyme (ACE), during fracture healing.
In a murine femur fracture model, animals were treated with the ACE inhibitor perindopril or vehicle only. Fracture healing was analysed after 2, 5 and 10 weeks using X-ray, micro-CT, histomorphometry, immunohistochemistry, Western blotting and biomechanical testing.
ACE was expressed in osteoblasts and hypertrophic chondrocytes in the periosteal callus during fracture healing, accompanied by expression of the angiotensin type-1 and type-2 receptors. Perindopril treatment reduced blood pressure and bone mineral density in unfractured femora. However, it improved periosteal callus formation, bone bridging of the fracture gap and torsional stiffness. ACE inhibition did not affect cell proliferation, but reduced apoptotic cell death. After 10 week treatment, a smaller callus diameter and bone volume after perindopril treatment indicated an advanced stage of bone remodelling.
Our study provides evidence for a local RAS in bone that influenced the process of fracture healing. We show for the first time that inhibition of ACE is capable of accelerating bone healing and remodelling.
British Journal of Pharmacology 03/2010; 159(8):1672-80. · 4.41 Impact Factor
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ABSTRACT: We describe the case of a 6-year-old girl with post-traumatic torticollis after falling on her head. The suspected fractures of the dens axis and/or atlas were ruled out after performing CT and MRI examinations as well as dynamic fluoroscopy. Radiological findings showed no further instability but there was a congenital non-fusion of the posterior arch and an age-appropriate non-fused anterior arch of the atlas. In addition to discoligamental injuries and fractures, congenital anomalies and normal variants of the immature anatomy of the cervical spine should also be considered in the diagnosis of the pediatric cervical spine after trauma.
Der Unfallchirurg 02/2010; 113(3):230-4. · 0.61 Impact Factor
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ABSTRACT: The diagnosis and treatment of pelvic ring injuries is demanding. Therefore, standardized classifications characterizing the stability and severity of pelvic ring fractures are essential to define clear algorithms for the treatment of these injuries. The first part of this article provides an overview of the etiology and classification of pelvic ring injuries. We recommend the AO classification to assess the stability of pelvic ring fractures. This classification includes 3 types of pelvic ring fractures: stable fractures (type A), fractures with only rotational instability (type B), and fractures with complete (rotational and translational) instability. To describe the severity of the injury, pelvic ring fractures can be classified as plain pelvic fractures, which include fractures with osteoligamentous instability, but without significant concomitant injuries to the soft tissue, versus complex pelvic fractures, which are combined with severe peripelvic soft tissue lesions.While plain pelvic fractures allow thorough clinical and radiological diagnostics, complex pelvic traumata represent a life threatening situation for the patient, which needs immediate emergency measures. In the second part of the this review we present current data of the German Pelvic Multicenter Study III (DGU/AO) on the epidemiology and treatment of pelvic ring injuries deriving from a study population of more than 3000 patients. In addition, we compare the present data with those of the German Pelvic Multicenter Study I and highlight changes in the epidemiology and treatment of pelvic ring fractures during the past decades. Taken together, we could observe an increasing number of elderly patients sustaining pelvic ring fractures.Regarding the treatment of pelvic ring fractures we found a rising use of external fixators and SI screws, while the number of laparotomies has markedly decreased.
Acta chirurgiae orthopaedicae et traumatologiae Cechoslovaca 01/2010; 77(6):450-6. · 1.63 Impact Factor
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Injury 08/2009; 41(10):1093-4. · 1.98 Impact Factor
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Injury 07/2009; 40(10):1115-7. · 1.98 Impact Factor
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L Claes,
J Schmalenbach,
M Herrmann,
I Olkü,
P Garcia,
T Histing,
R Obeid,
H Schorr,
W Herrmann, T Pohlemann,
M D Menger,
J H Holstein
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ABSTRACT: Hyperhomocysteinemia (HHCY) has been shown to disturb bone metabolism and to increase the incidence of osteoporosis and osteoporotic fractures. However, there is a complete lack of information on whether these metabolic alterations affect bone repair. The aim of this study was to analyze the impact of HHCY on fracture healing. One group of mice was fed a homocystine-supplemented diet (n = 12), whereas another group received the accordant standard diet for control (n = 13). Four weeks after the stable fixation of a closed femoral fracture, animals were killed to prepare bones for histomorphometric and biomechanical analyses. In addition, blood samples were obtained to evaluate serum concentration of homocysteine (HCY). Quantitative analysis of blood samples revealed severe HHCY as indicated by significantly increased serum concentrations of HCY in animals fed the homocystine-supplemented diet (102.2 +/- 64.5 micromol/l) compared to controls (2.8 +/- 1.5 micromol/l). Biomechanical evaluation of bone repair revealed significantly decreased bending stiffness of the femora of homocystine-fed animals (45.5 +/- 18.2 N/mm) compared with controls (64.6 +/- 15.8 N/mm). Histomorphometric analysis demonstrated a slightly smaller callus diameter in HHCY animals but no significant differences in the tissue composition of the callus. In conclusion, the homocystine-supplemented diet leads to severe HHCY, which is associated with an impaired biomechanical quality of the healing bone.
Calcified Tissue International 07/2009; 85(1):17-21. · 2.38 Impact Factor
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ABSTRACT: Scaffolds for tissue engineering should be biocompatible and stimulate rapid blood vessel ingrowth. Herein, we analyzed in vivo the biocompatibility and vascularization of three novel types of biodegradable porous polyurethane scaffolds. The polyurethane scaffolds, i.e., PU-S, PU-M and PU-F, were implanted into dorsal skinfold chambers of BALB/c mice. Using intravital fluorescence microscopy we analyzed vascularization of the implants and venular leukocyte-endothelial cell interaction in the surrounding host tissue over a 14 day period. Incorporation of the scaffolds was analyzed by histology, and a WST-1 assay was performed to evaluate their cell biocompatibility in vitro. Our results indicate that none of the polyurethane scaffolds was cytotoxic. Accordingly, rolling and adherent leukocytes in venules of the dorsal skinfold chamber were found in a physiological range after scaffold implantation and did not significantly differ between the groups, indicating a good in vivo biocompatibility. However, the three scaffolds induced a weak angiogenic response with a microvessel density of only approximately 47-60 and approximately 3-10cm/cm(2) in the border and centre zones of the scaffolds at day 14 after implantation. Histology demonstrated that the scaffolds were incorporated in a granulation tissue, which exhibited only a few blood vessels and inflammatory cells. In conclusion, PU-S, PU-M and PU-F scaffolds may be used to generate tissue constructs which do not induce a strong inflammatory reaction after implantation into patients. However, the scaffolds should be further modified or conditioned in order to accelerate and improve the process of vascularization.
Acta biomaterialia 03/2009; 5(6):1991-2001. · 3.98 Impact Factor
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J H Holstein,
M Klein,
P Garcia,
T Histing,
U Culemann,
A Pizanis,
M W Laschke,
C Scheuer,
C Meier,
H Schorr, T Pohlemann,
M D Menger
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ABSTRACT: The immunosuppressive drug rapamycin (RAPA) prevents rejection in organ transplantation by inhibiting interleukin-2-stimulated T-cell division. Rapamycin has also been suggested to possess strong anti-angiogenic activities linked to a decrease in production of vascular endothelial growth factor (VEGF). Angiogenesis and VEGF are thought to play a crucial role in fracture healing and as osteoporotic and traumatic fractures are common complications in immunosuppressed, organ transplantation patients, we conducted this study to analyze the effect of rapamycin treatment on bone repair.
We investigated the effect of rapamycin treatment on bone repair in a murine closed femur fracture model using radiological, histomorphometric, immunohistochemical, biomechanical and protein biochemical analyses.
X-ray analyses demonstrated that rapamycin treatment inhibits callus formation after two weeks of fracture healing. The radiologically observed lack of callus formation was confirmed by histomorphometric analyses, which revealed a significantly diminished callus size and a reduced amount of bone formation when compared with vehicle-treated controls. Biomechanical testing further demonstrated that rapamycin significantly reduces torsional stiffness of the callus. Interestingly, this effect was associated with decreased vessel formation; a diminished proliferation of osteoblasts, endothelial cells and periosteal cells; and a reduced VEGF expression in hypertrophic chondrocytes. After five weeks treatment, however, the negative impact of rapamycin on fracture healing was overcome.
Thus, rapamycin initially delays fracture healing, most probably by inhibiting cell proliferation and neovascularization in the callus. These undesirable effects should be considered when rapamycin is administered to patients sustaining bone fractures.
British Journal of Pharmacology 08/2008; 154(5):1055-62. · 4.41 Impact Factor
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ABSTRACT: Evaluation of a reduction is currently a static procedure. The purpose of this study was to evaluate a model for analyzing the whole dynamic component of the reduction path up to the final result: the optimal reduction. The entire reduction procedure should be able to be retrospectively analyzed, both qualitatively and quantitatively.
Two examiners of different experience levels had to solve multiple predefined tasks, which were noted with the assistance of a motion tracking system in all space axes. The noted paths of reduction were then analyzed with the MATLAB program and some additional quantitative and qualitative tools.
Both examiners had to accomplish a typical number of characteristic movement samples in typical number, in order to arrive at the same final result. After the temporal component was eliminated, the reduction process showed typical turning points that represented essential conditions for achieving an optimal result.
Using the presented model the paths in a reduction process can be achieved as data in a simple manner. These data are supplied in a second work procedure of an automated evaluation. Thus, multiple possibilities result for retrospective analysis of the data regarding the dynamic process of a reduction.
Der Unfallchirurg 07/2008; 111(6):395-402. · 0.61 Impact Factor
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ABSTRACT: Epiphysiolysis of the dens axis at the infant age is a rare injury, which must be surely clarified at car accidents with frontal application of force at medium high speed. We report of a small patient sitting in a child seat, who suffered a epiphysiolysis of the dens axis, which was initially not diagnosed, due to a abrupt deceleration in the context of a car accident. The epiphysiolysis of the dens axis could be secured with the aid of conventional radiography, MRT and CT. The delayed conservative treatment due to the anamnesis was then complicationless.
Der Unfallchirurg 03/2008; 111(9):749-53. · 0.61 Impact Factor
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ABSTRACT: Gender dimorphism in clinical manifestation of sepsis, hemorrhage, and trauma is still under investigation. Several experimental studies have indicated a protective effect of estrogen. Nonetheless, the effect of gender on hepatic ischemia/reperfusion remains controversially discussed, and the influence of estrogen is still unclear. In the present study, we investigated whether hepatic ischemia/reperfusion (I/R) injury is gender-dependent and if hepatic microvascular reperfusion injury can be prevented by estrogen.
Eight female and eight male Sprague-Dawley rats were subjected to 90 min left lobar ischemia followed by 60 min reperfusion. Additional six males were pretreated with 17beta-estradiol 24 h before I/R. Six female and six male rats served as nonischemic sham animals. By means of intravital microscopy, sinusoidal perfusion, leukocyte-endothelial cell interaction, and Kupffer cell activity were analyzed. Finally, arterial blood and liver tissue samples were taken for histomorphological analysis and liver enzyme determination.
After hepatic ischemia/reperfusion, animals revealed a significant gender-specific impairment of hepatic microcirculation, whereas Kupffer cell depression, sinusoidal perfusion failure, leukocyte-endothelial cell interaction within post sinusoidal venules, and parenchymal liver cell damage were more pronounced in male animals. Pretreatment with estrogen caused a normalization of Kupffer cell dysfunction and an amelioration of sinusoidal perfusion failure and venular leukocyte-endothelial cell interaction. However, estrogen did not protect from manifestation of post ischemic parenchymal cell damage.
Hepatic ischemia and reperfusion generate a gender-specific occurrence of microvascular injury, which seems to be partially mediated by estrogen. However, additional factors may contribute to the initial post ischemic parenchymal cell damage.
International Journal of Colorectal Disease 02/2008; 23(1):113-9. · 2.38 Impact Factor
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ABSTRACT: Mouse models are of increasing interest to study the molecular aspects of fracture healing. Because biomechanical factors greatly influence the healing process, stable fixation of the fracture is of interest also in mouse models. Unlike in large animals, however, there is a lack of mouse models which provide stable osteosynthesis. The purpose of this study was therefore to develop a technique for a more stable fixation of femoral fractures in mice and to analyze the impact of stability on the process of fracture healing. The new technique introduced herein includes an intramedullary pin and an extramedullary metallic clip. Ex vivo biomechanical analysis revealed a significantly higher implant stiffness of our pin-clip technique when compared with previously described intramedullary fixation techniques. In vivo, we studied the course of healing after the more stable fixation with our pin-clip technique and compared the results with that observed after unstable fixation with the pin-clip technique after cutting the clip. After 2 and 5 weeks of fracture healing radiological analysis demonstrated that the more stable fixation with the pin-clip technique results in a significantly higher union rate compared to the unstable fixation. Torsional stiffness at 5 weeks was almost 3-fold of that measured after unstable fixation. Histomorphological analysis further showed that fractures stabilized with the pin-clip technique healed with a smaller periosteal callus area, an increased fraction of bone and a reduced amount of fibrous tissue. Of interest, the pin-clip fixation showed reliable union after 5 weeks, whereas the unstable pin fixation did not regularly achieve adequate fracture healing. In conclusion, we introduce a novel, easily applicable internal osteosynthesis technique in mice, which provides rotational stability after femoral fracture fixation. We further show that a more stable osteosynthesis significantly improves the process of fracture healing also in mice.
Journal of Biomechanics 02/2008; 41(8):1689-96. · 2.43 Impact Factor
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ABSTRACT: In recent years, the closed reduction and percutaneous fixation of posterior pelvic ring fractures by sacroiliac screws has become a well established treatment option for stabilization of posterior pelvic ring disruptions. Stable percutaneous pelvic ring fixation also implies a very low complication rate, e.g., in operative blood loss, wound healing, and operative time. To avoid malpositioning of the screws, sufficient reduction and radiologic visualization are essential. The surgical technique has been described in several studies; however, great importance is attached to the personal experience of the surgeon. Therefore, this study was conducted to establish a standard procedure that allows different surgeons a safe positioning of sacroiliac screws.
A total of 41 injuries of the posterior pelvic ring were stabilized with 73 sacroiliac lag screws inserted by 7 different surgeons using a standardized technique. In all cases adequate reduction of the fracture and radiologic visualization were achieved. No wound infections, no relevant bleedings, and no spiral fractures of screws were observed. In two cases malpositioning led to revision of the screws. Of interest, one case of S1 paresthesia resulting from a malpositioned screw could be revised. In contrast, two cases of screw loosening and one case of screw bending did not require further intervention.
We conclude that safe positioning of the sacroiliac screws was accomplished by all surgeons given a standardized technique. For safe insertion preparation of the patients, accurate visualization of the fracture zone, and potential closed reduction is always required.
Der Unfallchirurg 09/2007; 110(8):669-74. · 0.61 Impact Factor
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ABSTRACT: Reliable osteosynthesis for fractures in the different regions of the human pelvis are described in the literature while there is no common and satisfying treatment for unstable sacral fractures. Because of the posterior pelvic rings special anatomic conditions a local plate osteosynthesis seems to be advantageous. In many fields of modern fracture treatment locking implants show superior results. The prototype of a local locking plate osteosynthesis was compared to a common local plate and two sacroiliac screws.
The implants were tested using six plastic models of the pelvis and three embalmed human specimens. A Tile C1 fracture was created by disruption of the pubic symphysis and a transforaminal osteotomy. The specimens were exposed to axial loading in an upright single-leg stance with a maximum of 800 N for the plastic models and 200 N for the human specimens. An ultrasonic-based measuring system recorded translations (X, Y, Z) and rotations (alpha, beta, gamma). Parameters such as pattern of motion, translation/rotation, load to failure and remaining dislocation were evaluated.
Concerning most of the evaluated parameters the local plate osteosynthesis was inferior compared with two sacroiliac screws. There were no significant differences between the locking implant and the local plate osteosynthesis. Compared with the two sacroiliac screws the locking implant shows biomechanically equal results but allows greater anterior rotation and remaining dislocation. Because of the lower bone quality, the results from the anatomic specimen tested were not utilisable.
The locking implant is biomechanically an alternative compared with two sacroiliac screws. Problems occurred due to the preset direction of the locking head screws.
Der Unfallchirurg 07/2007; 110(6):528-36. · 0.61 Impact Factor
