Article

A prospective evaluation of tunnel enlargement in anterior cruciate ligament reconstruction with hamstrings: Extracortical versus anatomical fixation

Authors:
  • Perth Orthopaedics &Sportsmed centre
  • ARCUS Sportsclinic Pforzheim, Germany
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Abstract

Changes in the femoral and tibial bone tunnel were studied prospectively after arthroscopic ACL reconstruction with quadruple hamstring autograft. To determine whether tunnel enlargement can be decreased by fixing the graft close to the joint line having a stiffer fixation construct we compared "anatomical" (one absorbable interference screw femorally, and bicortical fixation with two absorbable interference screws tibially) and extracortical fixation techniques (Endobutton femorally, and two no. 6 Ethibond sutures over a suture washer tibially). Over a 2-year period we evaluated 60 patients clinically (IKDC scale, Cincinnati Knee Score, KT-1000) and radiographically (confirmed by MRI). The operated knee was radiographed immediately postoperatively and 6 and 24 months postoperatively. The femoral and tibial bone tunnel diameter was measured on anteroposterior and lateral images, and the tunnel area was calculated and compared to the initial area calculated from the perioperative drill size. In the "anatomical" group the immediately postoperative bone tunnel area was 75% larger than the initial tunnel area, after 6 months it was increased another 31%, and between 6 and 24 months it remained basically unchanged. In the "extracortical" group there was no significant enlargement immediately postoperatively, but after 6 months it was 65% larger than the initial area of drill and graft size, and between 6 and 24 months it decreased to 47%. There was no correlation between the amount of tunnel enlargement and clinical scores or KT-1000 measurement. Arthroscopic ACL reconstruction with quadruple hamstring autograft is associated with bone tunnel enlargement. Using a purely extracortical fixation technique thus significantly increased the tibial and femoral tunnel area during the first 6 postoperative months, while it decreased slightly thereafter. The insertion of large interference screws apparently not only compresses the graft in the bone tunnel but also significantly enlarges the bone tunnel itself. The immediate enlargement at the time of the operation is followed by a reduced further enlargement at 6 months and then stabilization. Tunnel widening did not influence clinical outcome over a 2-year period.

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... Various causes have been suggested including discrepancy between size of graft and bone tunnel, graft-tunnel motion (Wind-shield wiper effect and bungee effect), thermal necrosis of bone during drilling, early aggressive rehabilitation etc. 6-9 Tunnel enlargement is known to occur in first 6 months after ACL reconstruction and declines thereafter. 10,11 It is not seen 2 years after ACL reconstruction. No study has yet identified any effect on clinical stability or arthrometer measurements due to tunnel enlargement. ...
... No study has yet identified any effect on clinical stability or arthrometer measurements due to tunnel enlargement. [11][12][13][14] Nevertheless, long-term implications and difficulty in revision surgery are matters of concern. 14, 16 With autologous hamstring grafts, extracortical or periosteal fixation devices like suture disc or endobutton are very popular, but they are far away from the articular surface and are associated with graft tunnel motion, and suture-stretch out leading to concerns of delayed biological incorporation, tunnel enlargement and secondary rotational and anterior instability. ...
... 15 Buelow, Fauno, Iorio have all concluded that there was a significant reduction of tunnel widening using fixation points close to the joint compared to the system where the distance between fixation points is long. 11,14,28 In our study also, there was significantly less tunnel enlargement (p-value) with the use of interference screw as compared to suture disc. We have observed tunnel enlargement in the early postoperative period (2 weeks) probably because we have used extraction drilling. ...
Article
p class="abstract"> Background: It is important to study the cause of tunnel widening which occurs after anterior cruciate ligament (ACL) reconstruction as it may affect tendon to bone healing. Amount of tunnel enlargement that happens after different fixation methods like interference screw or suture discs needs to be compared. The objective of the study was to test the hypothesis that aperture fixation (interference screw) reduces tunnel enlargement compared to suspensory fixation (suture disc) due to reduced graft tunnel motion. Methods: 24 bone tunnel diameters in 12 patients were evaluated by CT scan postoperatively after ACL reconstruction to measure tunnel widening. Two groups were formed, one consisting of 14 tunnels fixed by interference screws (IFS) and other consisting of 10 tunnels fixed with suture disc (SD). The difference between the two groups was compared by unpaired student’s t test . Results: The mean tunnel widening in IFS group was 0.414mm while that in the SD group was 1.23mm. The difference between the means of the two groups was statistically significant (p<0.001). Conclusions: Tunnel widening phenomenon was significantly less with anatomic IFS fixation as compared to suture disc fixation probably due to reduced motion of graft within the walls of bony tunnel and consequently better graft healing. </p
... 3 Some authors, however, have questioned the use of biomaterials, which could cause local inflammation during their absorption, leading to an enlargement of the bone tunnels. 5,6 However, this enlargement has multifactorial causes 7 and does not interfere with the clinical outcome, 1,5,8,9 it occurs also with the use of non-absorbable screws, and in extracortical fixation, without material inside the bone tunnel, like the "EndoButton". 10 The objective of this study is to compare the enlargement of bone tunnels one year after ACL reconstruction, with computed tomography (CT), among three types of interference screws: pure poly-lactic acid (PLDL), absorbable poly-lactic acid with tricalcium-phosphate (TCP), and polyether-ethylketone (PEEK). ...
... Some studies show greater enlargement of the tunnels with the use of indirect fixation, such as the extracortical "EndoButton" compared with the fixation within the tunnel as the interference screw. 8,13 However, Fauno 10 compared extracortical and direct fixation and found no significant difference between the two methods. It is believed that the greatest enlargement of the tunnels occurs within the first postoperative year 5,10 with little to no change in the time following. ...
... 20 However, Hwang 13 compared ACL reconstruction with the hamstring and press-fit fixation, believing that this would reduce the intra-tunnel synovial fluid and would have a smaller increase of the total tunnel volume, but no difference was found compared to the conventional technique. Although the enlargement of the bone tunnels is common in ACL reconstruction and has no correlation with the clinical outcome 5,8,9 we did not compare clinically the patients among the different groups. One limitation of our study was that the TCP group had a smaller number of patients compared to the other groups. ...
Article
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Objective: To compare the widening of bone tunnels between poly-etheretherketone (PEEK), absorbable polylactic acid DL (PLDL) and tricalcium phosphate (TCP) interference screws in anterior cruciate ligament (ACL) reconstruction. Methods: Three groups of patients undergoing ACL reconstruction with at least 1 year of follow-up using the out-in drilling technique and hamstring as a graft were assessed. The patients were divided according to the type of interference screw used (PEEK, PLDL and TCP). Computed tomography (CT) was performed to measure the greatest femoral and tibial tunnel widening regarding to the initial tunnel, and then it was compared between groups. Results: Mean widening in group 1 (PEEK) was 39.56% (SD 16%) in the femoral tunnel and 33.65% (SD 20%) in the tibia. In group 2 (PLDL) mean widening was 48.43% in the femoral tunnel (SD 18%) and 35.24% (SD 13%) in the tibial tunnel. In group 3 (TCP) mean widening was 44.51% in the femur (SD 14%) and 36.83% in the tibia (SD 14%). The comparison between groups (PLDL-PEEK, PLDL-TCP, PEEK-TCP) shows no statistically significant difference. Conclusion: Bone tunnel enlargement values after ACL reconstruction with the use of different types of materials (bioinert and biomaterials) of interference screws (PEEK, PLDL and TCP) were similar. Level of Evidence III, Comparative retrospective study.
... El ensanchamiento de los túneles se calculó según la fórmula de Buelow (13) , en la que se compara el diámetro radiológico final de seguimiento (mínimo 6 meses), respecto al diámetro inicial o intraoperatorio, expresando el resultado en forma de porcentaje: ...
... En cuanto al ensanchamiento, las medias de las medidas iniciales y finales se detallan en la Tabla 2. Tras un seguimiento medio de 15 meses en el grupo A y de 12 meses en el grupo R, si tenemos en cuenta la fórmula de Buelow (13) (Tabla 3), observamos que el túnel femoral ha aumentado un 42,10% en la radiografía AP en el grupo A tratado con tornillo anterógrado. Y en el grupo R, tratado con tornillo retrógrado, el túnel femoral se ha ensanchado un 10% menos en el plano coronal (radiografía AP). ...
... En nuestros resultados, podemos observar que hay un menor ensanchamiento en el grupo tratado con tornillo retrógrado tanto en el túnel femoral como en el túnel tibial, encontrando un 41% en túnel femoral AP, un 32% en túnel tibial AP y un 35% en túnel tibial lateral (9) . Buelow et al., en su estudio, observaron que con una fijación con tornillo interferencial se producía un menor ensanchamiento que con una fijación cortical (13) . Fauno y Kaalund, en un estudio aleatorizado donde compararon 2 grupos de 50 pacientes tras reconstrucción de LCA con isquiotibiales, uno con fijación transfemoral (TransFix®) y tornillo interferencial en tibial y otro con fijación cortical femoral (EndoButton®) y fijación de la plastia tibial a poste con tornillo bicortical, concluyen que la posición de los sitios de fijación y el tipo de dispositivo de fijación son los principales factores en el desarrollo de ensanchamiento del túnel después de la cirugía de LCA (3,14) . ...
... Enlargement of the osseous tunnel after reconstruction of ACL has been a concern over past few years. Although it does not appear to affect the clinical outcome in the first 2 postoperative years, [15,16] long-term outcome of this phenomenon is not yet known and tunnel expansion may be clinically significant in revision surgery since the enlarged tunnels may complicate graft placement and fixation. [17] Buelow et al. [16] compared the effect of extracortical suspension fixation with anatomical fixation using interference screws on the tunnel enlargement. ...
... Although it does not appear to affect the clinical outcome in the first 2 postoperative years, [15,16] long-term outcome of this phenomenon is not yet known and tunnel expansion may be clinically significant in revision surgery since the enlarged tunnels may complicate graft placement and fixation. [17] Buelow et al. [16] compared the effect of extracortical suspension fixation with anatomical fixation using interference screws on the tunnel enlargement. They found that insertion of large interference screws not only compresses the graft in the bone tunnel but also significantly enlarges the bone tunnel itself. ...
... As with many other authors, [3,15,16,21,25,27] no significant association between tunnel enlargement and clinical results was found in this study. However, like most of the studies done so far, this is only a short-term evaluation of the clinical effects of tunnel enlargement. ...
Article
Full-text available
Context: Enlargement of osseous tunnels following anterior cruciate ligament (ACL) reconstruction is a newer discovery. This phenomenon is particularly valuable in planning for revision ACL reconstruction. Aim: The purpose of this study was to evaluate prospectively the increase in the size of the tibial and femoral bone tunnel following arthroscopic ACL reconstruction with quadrupled hamstring autograft and fixation with biodegradable interference screws. Materials and Methods: A prospective study was conducted on 10 patients who underwent arthroscopic ACL reconstruction with quadrupled hamstring autograft and fixation with biodegradable interference screws. Tunnel width was measured at post-operative 2 weeks and an average of 1‑year follow‑up (range: 10–13 months). Clinical evaluation was done as per the International Knee Documentation Committee form. Paired Student’s t‑test and linear regression were used for statistical analysis. Results: There was a mean 14% enlargementin the femoral tunnel (from 9 mm at post-operative 2 weeks to 10.3 mm at post-operative 1 year) and 18% enlargementin the tibial tunnel (from 10.4 mm at post-operative 2 weeks to12.2 mm at the post-operative 1‑year follow‑up).Both of these were statistically significant (P=0.005 for femoral tunnel enlargement and P = 0.008 for the enlargement of the tibial tunnel). No statistically significant associationn was noted between tunnel enlargement and clinical results. Conclusion: Compared to previous similar studies, less tunnel widening was observed in the present study. We come to a conclusion that less aggressiverehabilitation program and anatomical graft fixation technique can help achieve the goal of minimum tunnel enlargement after ACL reconstruction.
... B one tunnel enlargement (BTE) is known to potentially complicate revision surgery after failure of primary anterior cruciate ligament reconstruction (ACL-R) [1][2][3][4] because it leaves the femoral and tibial tunnels potentially unusable for graft fixation, often requiring staged management, and has a positive correlation with postoperative laxity. BTE after ACL-R has been a well-documented phenomenon in the literature since the early 1990s and has been reported frequently [1][2][3][4][5][6] . It is characterized by the widening of the tibial and femoral tunnels as seen postoperatively on radiographs and other imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI). ...
... It is characterized by the widening of the tibial and femoral tunnels as seen postoperatively on radiographs and other imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI). The reported prevalence is extremely variable, ranging from 0% to 74.26% 5 . It has been accepted that BTE might be a problem in cases of revision because a new tunnel may be difficult to establish in the setting of this bone loss. ...
... It may be apparent that as the techniques for the detection of microbial bioburden become more refined 65 , bacteria may be found to have a more important role in BTE. The presence of bacteria may account for some portion of the discrepancy in the rates of BTE among patients 5 . Although the postulation of microbial involvement in BTE remains a relatively new topic, it certainly provides an opportunity to decrease the rates of graft failure. ...
Article
Although anterior cruciate ligament reconstruction (ACL-R) yields generally favorable results, bone tunnel enlargement (BTE) commonly has been reported after ACL-R. While the exact clinical ramifications of tibial widening on functional outcomes are variable, it is thought that widening may potentially play a role in late failure following ACL-R. The prevalence of tunnel enlargement is related particularly to hamstring autografts, with some authors reporting rates ranging from 25% to 100% in femoral tunnels and 29% to 100% in tibial tunnels after ACL-R. BTE is difficult to manage, particularly in the setting of revision ACL-R. The mechanisms underlying BTE after ACL-R are associated with a complex interplay between biological and mechanical factors.
... In contrast to bonetendon-bone transplants, the artificial tendon-bone interface of hamstring grafts allows micromovements [10] and results in higher rates of tunnel enlargement [3,11]. Furthermore, graft fixation with interference screws was reported to be associated with enlarged bone tunnels when compared to extracortical fixation techniques [11][12][13][14]. Hybrid fixation technique combines both aperture and extracortical fixation, and was shown to increase fixation strength and stiffness in biomechanical and clinical studies [15][16][17][18]. ...
... To press the graft against the wall and, therefore, promote healing, usually a screw a few millimeters smaller compared to the tunnel diameter is used [19]. Moreover, the distance between the graft fixation points is reduced with an interference screw, resulting in decreased longitudinal graft motion (bungee cord effect) [12,20,21]. However, a considerable mismatch between the screw to the tunnel diameter might produce a mechanically unfavorable environment in that increased sagittal movements of the graft occur during flexion/extension of the knee (windshield wiper effect). ...
... The most important finding of this study was that tibial tunnel widening after primary ACL reconstruction with hybrid fixation is affected by the tunnel diameter covered by the interference screw: A tunnel coverage ratio of > 70% was beneficial regarding tibial tunnel widening. Previous studies reported enlarged bone tunnels with the insertion of interference screws when compared to other fixation techniques [11][12][13][14]. To be specific, Buelow et al. [12] investigated a purely extracortical fixation technique (with an Endobutton femorally, and two no. ...
Article
Full-text available
Introduction There is no evidence on screw diameter with regards to tunnel size in anterior cruciate ligament reconstruction (ACLR) using hybrid fixation devices. The hypothesis was that an undersized tunnel coverage by the tibial screw leads to subsequent tunnel enlargement in ACLR in hybrid fixation technique. Methods In a retrospective case series, radiographs and clinical scores of 103 patients who underwent primary hamstring tendon ACLR with a hybrid fixation technique at the tibial site (interference screw and suspensory fixation) were obtained. Tunnel diameters in the frontal and sagittal planes were measured on radiographs 6 weeks and 12 months postoperatively. Tunnel enlargement of more than 10% between the two periods was defined as tunnel widening. Tunnel coverage ratio was calculated as the tunnel diameter covered by the screw in percentage. Results Overall, tunnel widening 12 months postoperatively was 23.1 ± 17.1% and 24.2 ± 18.2% in the frontal and sagittal plane, respectively. Linear regression analysis revealed the tunnel coverage ratio to be a negative predicting risk factor for tunnel widening (p = 0.001). The ROC curve analysis provided an ideal cutoff for tunnel enlargement of > 10% at a tunnel coverage ratio of 70% (sensitivity 60%, specificity 81%, AUC 75%, p < 0.001). Patients (n = 53/103) with a tunnel coverage ratio of < 70% showed significantly higher tibial tunnel enlargement of 15% in the frontal and sagittal planes. The binary logistic regression showed a significant OR of 6.9 (p = 0.02) for tunnel widening > 10% in the frontal plane if the tunnel coverage ratio was < 70% (sagittal plane: OR 14.7, p = 0.001). Clinical scores did not correlate to tunnel widening. Conclusion Tibial tunnel widening was affected by the tunnel diameter coverage ratio. To minimize the likelihood of disadvantageous tunnel expansion-which is of importance in case of revision surgery-an interference screw should not undercut the tunnel diameter by more than 1 mm.
... 1,7,36 Tunnel enlargement is considered to occur under the influence of biological factors, which include tunnel infiltration of synovial fluid containing osteolytic cytokines, 8 and mechanical factors, which include micromotion at the tunnel aperture ("windshield wiper" and "bungee" effects), nonanatomic tunnel placement, and aggressive rehabilitation. 16 It remains controversial whether tunnel enlargement after ACL reconstruction affects clinical outcomes 5,11,17 or graft-to-bone integration in the tibial tunnel. ...
... The impact of tunnel enlargement on graft-to-bone integration after ACL reconstruction remains largely unclear, while the effect of tunnel enlargement on clinical outcomes has been discussed and is still under debate. 5,11,17,19,39 Harris et al 15 demonstrated that tunnel enlargement did not adversely affect the histological incorporation of the graft in a goat model. In the present study, we also found no association between tunnel enlargement and graft-tobone integration at 1 year after ACL reconstruction, the only exception being for AM tunnel enlargement on axial CT. ...
... In the present study, we also found no association between tunnel enlargement and graft-tobone integration at 1 year after ACL reconstruction, the only exception being for AM tunnel enlargement on axial CT. Tunnel enlargement has been reported to typically occur within 6 months after ACL reconstruction 5,19 and particularly within the first 6 weeks. 13,15 While it is possible that not only graft-to-bone integration but also bone ingrowth into the tunnel continued after tunnel enlargement reached a maximum (at 1 year after ACL reconstruction), we found that only AM tunnel enlargement on axial CT affected graft-to-bone integration. ...
Article
Full-text available
Background Remnant-preserving anterior cruciate ligament (ACL) reconstruction was introduced to improve clinical outcomes and biological healing. However, the influences of remnant preservation on tibial tunnel position and enlargement are still uncertain. Purpose To evaluate whether remnant-preserving ACL reconstruction influences tibial tunnel position or enlargement and to examine the relationship between tunnel enlargement and graft-to-bone integration in the tibial tunnel. Study Design Cohort study; Level of evidence, 2. Methods A total of 91 knees with double-bundle ACL reconstructions were enrolled in this study. ACL reconstruction was performed without a remnant (<25% of the intra-articular portion of the graft) in 44 knees (nonremnant [NR] group) and with remnant preservation in the remaining 47 knees (remnant-preserving [RP] group). Tibial tunnel position and enlargement were assessed using computed tomography (CT). Comparisons between groups were performed. Furthermore, graft-to-bone integration in the tibial tunnel was evaluated using magnetic resonance imaging, and the relationship between tunnel enlargement and graft-to-bone integration at 1 year after ACL reconstruction was assessed. Results A total of 48 knees (25 in NR group, 23 in RP group) were included; 19 and 24 knees in the NR and RP groups were excluded, respectively, because of graft reruptures and a lack of CT scans. There were no significant between-group differences in tibial tunnel position (P > .05). The degree of posterolateral tunnel enlargement in the axial plane was significantly higher in the RP group than that in the NR group (P = .007) 1 year after ACL reconstruction. The degree of anteromedial tunnel enlargement on axial CT was significantly smaller in knees with graft-to-bone integration than in those without integration (P = .002) 1 year after ACL reconstruction. Conclusion ACL reconstruction with remnant preservation did not influence tibial tunnel position and did not decrease the degree or incidence of tibial tunnel enlargement. At 1 year postoperatively, tunnel enlargement did not affect graft-to-bone integration in the posterolateral tunnel, but graft-to-bone integration was delayed in the anteromedial tunnel.
... They concluded Cross-pin method was superior to Endobutton fixation technique in terms of femoral tunnel widening. In another study in 60 patients in 2001 [10], authors compared anatomical fixation technique with extra-cortical fixation technique and the plain radiography was done at 2 days, 6 months and 24 months postoperatively. They reported anatomical method had more significant femoral tunnel area compared to the extracortical method. ...
... Also, implications of femoral tunnel widening for the clinical outcome is not clear. Consistent with previous findings, we did not find any correlation between tunnel widening and functional outcome [17,10,18]. In a review, Hoher et al. [19] discussed the possible theory about the etiology of bone tunnel enlargement. ...
Article
Full-text available
Background/aim An anterior cruciate ligament (ACL) rupture is a common sports-related injury requiring surgical intervention. With the advent of arthroscopically-assisted knee surgery, many graft fixation techniques for ACL have been developed. Femoral tunnel widening has been reported with a different incidence in various fixation techniques however its clinical significance is still not clear. We sought to compare femoral tunnel widening in patients undergoing arthroscopic anterior cruciate ligament (ACL) reconstruction with hamstring tendon autograft using either Endobutton or Double Cross-Pin technique. Methods In this prospective study, 40 patients with a diagnosis of unilateral, isolated ACL rupture were randomly assigned to either the Endobutton or Double Cross-Pin group. Patients were assessed for femoral tunnel widening using CT-scan and functional outcome was evaluated with international Knee Documentation Committee (IKDC) 2000 Subjective Knee Evaluation score and Lysholm score. Femoral tunnel diameter was determined based on intraoperative drill diameter and tunnel diameters on CT-scan performed every 6 months up to 18 months after surgery. Repeated measure analysis was used to compare the femoral tunnel diameter between two groups. Results All patients completed the study. The mean (±SD) age of Endobutton and Double Cross-Pin group was 29.75(±7.88), 31(±6.36), respectively. The mean change of femoral tunnel diameter for Endobutton group over 18 months was 3.05 and it was 2.34 for the Double Cross-Pin group. There was no statistically significant difference between two groups (p: 0.27). Also, the functional outcome was not significantly different between the two groups (p > 0.05). Conclusion Femoral tunnel widening after hamstring graft was not significantly different between Endobutton and Double Cross-Pin fixation techniques
... Postoperative tunnel widening is a phenomenon that has been widely reported with the use of soft-tissue grafts for anterior cruciate ligament (ACL) reconstruction [9,12,15,18,40]. Mechanical and biological factors have been postulated as causes of tunnel widening, but the phenomenon may be multifactorial. ...
... With button fixation, graft micromovements at the bone-tendon interface (bungee, windshield wiper effects) or synovial fluid migration into the tunnel might cause tunnel widening. Initial bone tunnel enlargement, bone and graft damage during insertion, allergic reactions and biological or immune responses to the foreign material are concerns with the use of biodegradable screws [9,11,21,44]. In the present study, all-inside ACL reconstruction with button fixation was association with less change in the tibial tunnel volume over 2 years in comparison with screw fixation. ...
Article
Purpose To compare tunnel widening and clinical outcome after anterior cruciate ligament reconstruction (ACLR) with interference screw fixation and all-inside reconstruction using button fixation. Methods Tunnel widening was assessed using tunnel volume and diameter measurements on computed tomography (CT) scans after surgery and 6 months and 2 years later, and compared between the two groups. The clinical outcome was assessed after 2 years with instrumented tibial anteroposterior translation measurements, hop testing and International Knee Documentation Committee (IKDC), Lysholm and Tegner activity scores. Results The study population at the final follow-up was 14 patients with screw fixation and 16 patients with button fixation. Tibial tunnels with screw fixation showed significantly larger increase in tunnel volume over time (P = 0.021) and larger tunnel diameters after 2 years in comparison with button fixation (P < 0.001). There were no significant differences in femoral tunnel volume changes over time or in tunnel diameters after 2 years. No significant differences were found in the clinical outcome scores. Conclusions All-inside ACLR using button fixation was associated with less tibial tunnel widening and smaller tunnels after 2 years in comparison with ACLR using screw fixation. The need for staged revision ACLRs may be greater with interference screws in comparison with button fixation at the tibial tunnel. The clinical outcomes in the two groups were comparable. Level of evidence II. RCT: Consort NCT01755819.
... As recommended by most manufacturers, the interference screw diameter should be similar or larger by + 1 mm for the tibial fixation in tendon grafts without bone blocks. Over dimensioned screws create strong initial compression, but can lead to eventual tunnel enlargement later on, creating difficulties in revision surgery (Buelow et al., 2002). ...
Article
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Background: Reliable biomechanical data about the strength of different tibial extracortical graft fixation devices is sparse. This biomechanical study compares the properties of tibial graft fixation in ACL reconstruction with either the ACL Tight Rope™ or the Rigid Loop Adjustable™ device. The hypothesis was that both fixation devices would provide comparable results concerning gap formation during cyclic loading and ultimate failure load. Methods: Sixteen sawbone tibiae (Sawbones™) underwent extracortical fixation of porcine flexor digitorum profundus grafts for ACL reconstruction. Either the ACL Tight Rope™ (Arthrex) or the Rigid Loop Adjustable™ (DePuy Mitek) fixation device were used, resulting in 2 groups with 8 specimens per group. Biomechanical analysis included pretensioning the constructs 10 times with 0.75 Hz, then cyclic loading of 1,000 position-controlled cycles and 1,000 force-controlled cycles applied with a servohydraulic testing machine. Elongation during cyclic loading was recorded. After this, ultimate failure load and failure mode analysis were performed. Results: No statistically significant difference could be noted between the groups regarding gap formation during cyclic loading (4.6 ± 2.6 mm for the Rigid Loop Adjustable™ vs. 6.6 ± 1.5 mm for the ACL Tight Rope™ (p > 0.05)), and ultimate failure loads (980 ± 101.9 N for the Rigid Loop Adjustable™ vs. 861 ± 115 N ACL Tight Rope™ (p > 0.05)). Conclusion: ACL Tight Rope™ and the Rigid Loop Adjustable™ fixation devices yield comparable biomechanical results for tibial extracortical graft fixation in ACL reconstruction. These findings may be of relevance for the future surgical decision-making in ACL reconstruction. Randomized controlled clinical trials comparing both fixation devices are desirable for the future.
... Some papers have reported post-ACL reconstruction bone tunnel enlargement to be unrelated to the clinical score or knee stability. However, during revision ACL reconstruction surgery, this enlargement makes it difficult to create the new femoral tunnel in the proper position and may lead to failure, because one of the most frequent causes for the failure of revision ACL reconstruction is femoral tunnel mal-position [8,11,18,44]. This point highlights the clinical relevance of post-ACL reconstruction bone tunnel enlargement. ...
Article
Purpose This study aimed to retrospectively compare the enlargement and migration of the femoral tunnel aperture after anatomic rectangular tunnel anterior cruciate ligament (ACL) reconstruction with a bone–patella tendon–bone (BTB) or hamstring tendon (HT) graft using three-dimensional (3-D) computer models. Methods Thirty-two patients who underwent ACL reconstruction and postoperative computed tomography (CT) at 3 weeks and 6 months were included in this study. Of these, 20 patients underwent ACL reconstruction with a BTB graft (BTBR group), and the remaining 12 with an HT graft (HTR group). The area of the femoral tunnel aperture was extracted and measured using a 3-D computer model generated from CT images. Changes in the area and migration direction of the femoral tunnel aperture during this period were compared between the two groups. Results In the HTR group, the area of the femoral tunnel aperture was significantly increased at 6 months compared to 3 weeks postoperatively (P < 0.05). The average area of the femoral tunnel aperture at 6 months postoperatively was larger by 16.0 ± 12.4% in the BTBR group and 41.9 ± 22.2% in the HTR group, relative to that measured at 3 weeks postoperatively (P < 0.05). The femoral tunnel aperture migrated in the anteroinferior direction in the HTR group, and only in the inferior direction in the BTBR group. Conclusions The femoral tunnel aperture in the HTR group was significantly more enlarged and more anteriorly located at 6 months after ACL reconstruction, compared to the BTBR group. Level of evidence IV.
... С другой стороны, применение интерферентных винтов также способствует расширению тоннелей. В одном из исследований, где сравнивались эти способы фиксации, было выявлено, что расширение происходит и в том, и в другом случае, только при применении винтов это проявляется сразу за счет разрушения винтом пограничной кости, а при кортикальной фиксации расширение появляется в течение первых 6 мес., затем оно уменьшается [27]. ...
Article
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The study purpose — to evaluate the clinical results and the condition of bone tunnels after anterior cruciate ligament reconstruction with a semitendinosus tendon graft using cortical fixation and corrugated sutures. Materials and Methods. The results anterior cruciate ligament reconstruction with a semitendinosus tendon autograft were analyzed in 57 patients aged 18 to 53 years. The patients of the first group (n = 27) underwent anterior cruciate ligament reconstruction with a semitendinosus tendon graft using cortical fixation on the femur and tibia in combination with corrugated sutures at the proximal and distal ends of the graft. The patients of the second group (n = 30) underwent anterior cruciate ligament reconstruction in a similar way, but without the use of corrugated sutures. Clinical results were assessed using the Lysholm and IKDC scales. The degree of bone tunnels widening was evaluated by CT data in 6 months after the surgery. Results . In the first group, the degree of postoperative bone tunnels widening was significantly lower (for the femoral tunnel by 18% and tibial — by 17%) compared with the second group (for the femoral tunnel by 30% and tibial — by 31%). Scores by the IKDC 2000 and Lysholm scales were higher in the corrugated sutured group. Although, the treatment outcome was interpreted as equally good for both groups. The time for graft preparation was on average 6 minutes longer in the first group. This slightly increased the duration of the surgery. Conclusion . The anterior cruciate ligament reconstruction with a semitendinosus tendon graft using cortical fixation on the femur and tibia in combination with corrugated sutures ensured the tight contact of the tendon inside the bone tunnels without additional implants and reduced the degree of tunnels widening. This is important for a possible re-grafting. The proposed method does not significantly affect the clinical outcomes.
... As the graft and surrounding cancellous bone are compacted during screw insertion, leading to initial bone tunnel widening and possible graft laceration [12,32,33], the expected biomechanical advantages of increasing the diameter of the screws need to be evaluated versus these risks. ...
Article
Background: Ideal diameter for tibial interference screw fixation of the anterior cruciate ligament (ACL) graft remains controversial. Tibial graft fixation with screws matching the tunnel diameter vs. one-millimetre oversized screws were compared. Methods: In 32 cadaveric porcine tibiae, bovine extensor tendons with a diameter of eight millimetres were fixed in (I) a primary ACL reconstruction scenario with eight-millimetre tibial tunnels (pACL), with eight-millimetre (pACL-8) vs. nine-millimetre (pACL-9) screws, and (II) a revision ACL reconstruction scenario with enlarged tunnels of 10 mm (rACL), with 10-mm (rACL-10) vs. 11-mm (rACL-11) screws. Specimens underwent cyclic loading with low and high load magnitudes followed by a load-to-failure test. Graft slippage and ultimate failure load were recorded. Results: In comparison with matched-sized screws (pACL-8), fixation with oversized screws (pACL-9) showed with significantly increased graft slippage during cyclic loading at higher load magnitudes (1.19 ± 0.23 vs. 1.98 ± 0.67 mm; P = 0.007). There were no significant differences between the two screw sizes in the revision scenario (rACL-10 vs. rACL-11; P = 0.38). Graft fixation in the revision scenario resulted in significantly increased graft slippage in comparison with fixation in primary tunnels at higher loads (pACL vs. rACL; P = 0.004). Pull-out strengths were comparable for both scenarios and all screw sizes (P > 0.316). Conclusions: Matched-sized interference screws provided better ACL graft fixation in comparison with an oversized screw diameter. In revision cases, the fixation strength of interference screws in enlarged tunnels was inferior to the fixation strength in primary tunnels.
... 25 The tunnel measurement was taken digitally at 10 mm from the intra-articular outlet of both the femoral and tibial tunnels without coalition in the OA, OS, and OC views according to previous studies. 7,10,25,44 Measurement of the tunnel cross-sectional area was also taken digitally at 10 mm from the intra-articular outlet of both the femoral and tibial tunnels without coalition in the OA view using ImageJ software (National Institutes of Health) (Figures 4 and 5). First, a digital image file of an OA CT scan was opened using ImageJ. ...
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Background The effects of remnant tissue preservation on tunnel enlargement after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction have not yet been established. Hypothesis The preservation of ACL remnant tissue may significantly reduce the degree and incidence of tunnel enlargement after anatomic double-bundle ACL reconstruction, while the remnant-preserving procedure may not significantly increase the incidence of tunnel coalition after surgery. Study Design Cohort study; Level of evidence, 2. Methods A total of 79 patients underwent anatomic double-bundle ACL reconstruction. Based on the Crain classification of ACL remnant tissue, 40 patients underwent the remnant-preserving procedure (group P), and the remaining 39 patients underwent the remnant-resecting procedure (group R). There were no differences between the 2 groups concerning all background factors, including preoperative knee instability and intraoperative tunnel positions. All patients were examined using computed tomography and a standard physical examination at 2 weeks and 1 year after surgery. Results During surgery, the femoral and tibial anteromedial (AM) tunnel sizes in both groups averaged 6.6 and 6.5 mm, respectively. The femoral and tibial posterolateral (PL) tunnel sizes in both groups averaged 6 and 6 mm, respectively. There were no differences in the intraoperative tunnel positions and tunnel sizes between groups. Concerning the femoral AM tunnel, the degree of tunnel enlargement in the oblique coronal and oblique axial views in group P was significantly less than that in group R (P = .0068 and .0323, respectively). Regarding the femoral AM tunnel cross-sectional area, the degree and incidence of tunnel enlargement in group P were significantly less than those in group R (P = .0086 and .0278, respectively). There were no significant differences in tunnel coalition between groups. In each group, there were no significant relationships between tunnel enlargement and each clinical outcome. Conclusion Remnant preservation in anatomic double-bundle ACL reconstruction reduced enlargement of the femoral AM tunnel and did not increase the incidence of tunnel coalition. This is one of the advantages of remnant-preserving ACL reconstruction.
... В одном из исследований, посвященных сравнению накостной фиксации и фиксации интерферентным винтом, выявлено, что расширение костных тоннелей происходит и в том, и в другом случае, только при фиксации винтами это происходит сразу за счет сминания стенки канала винтами, а при накостной фиксации -в течение первых 6 мес, а затем оно уменьшается. В этом же исследовании показано, что расширение костных тоннелей никак не влияло на стабильность сустава и клинический результат в течение 2-летнего периода наблюдения [4]. ...
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Purpose: to modify the cortical technique of quadrupled semitendinosus autograft fixation for anterior cruciate ligament reconstruction that enables to achieve tight contact of the tendon within the bone tunnels.Material and methods. Several described methods of graft fixation directed to the formation of maximum contact area between the popliteus tendon graft and the bone are analyzed. In the proposed technique a semitendinosus graft is fixed by cortical fixatives. During graft placement its proximal and distal ends are corrugated and increase in diameter providing additional close intra-tunnel fixation of the graft. Testing for rupture was performed on the material (6 semitendinosus tendons) from 3 cadavers. Potential fixation tightness within the tunnels was assessed by the degree of graft diameter enlargement after its placement.Results. At corrugated sutures tightening the proximal and distal diameters of the graft ends increased by 2.5±0.55 and 2.67±0.55 mm, respectively. Testing for rupture showed elastic deformation mean value of 364.83±69.16 N. Conclusion. The proposed modification for cortical technique of semitendinosus autograft fixation enables to ensure the close contact of the tendon within the bone tunnels and sufficient strength for the patients’ rehabilitation.
... Although most previous studies did not report an association between tunnel widening and adverse clinical outcomes, large tunnels may compromise graft fixation during revision surgery or may necessitate two-stage surgery [13][14][15][16][17]. Therefore, the purpose of our study was to compare tunnel widening and clinical outcomes after ACLR with adjustable-loop femoral cortical suspensory fixation to those with interference screw fixation. ...
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Background: Although the use of adjustable-loop suspensory fixation has increased in recent years, the influence of the shortcomings of suspensory fixation, such as the bungee-cord or windshield-wiper effects, on tunnel widening remains to be clarified. Hypothesis/Purpose: The purpose of this study was to compare adjustable-loop femoral cortical suspensory fixation and interference screw fixation in terms of tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR). We hypothesized that tunnel widening in the adjustable-loop femoral cortical suspensory fixation (AL) group would be comparable to that in the interference screw fixation (IF) group. Methods: This study evaluated patients who underwent primary ACLR at our institution between March 2015 and June 2019. The femoral and tibial tunnel diameters were measured using plain radiographs in the immediate postoperative period and 2 years after ACLR. Tunnel widening and clinical outcomes (Lysholm score, 2000 International Knee Documentation Committee subjective score, and Tegner activity level) were compared between the two groups. Results: There were 48 patients (mean age, 29.8 ± 12.0 years) in the AL group and 44 patients (mean age, 26.0 ± 9.5 years) in the IF group. Tunnel widening was significantly greater in the AL group than that in the IF group at the tibia anteroposterior (AP) middle (2.03 mm vs. 1.32 mm, p = 0.017), tibia AP distal (1.52 mm vs. 0.84 mm, p = 0.012), tibia lateral proximal (1.85 mm vs. 1.00 mm, p = 0.001), tibia lateral middle (2.36 mm vs. 1.03 mm, p < 0.001), and tibia lateral distal (2.34 mm vs. 0.85 mm, p < 0.001) levels. There were no significant differences between the two groups with respect to femoral tunnel widening and clinical outcomes. Conclusions: Tibial tunnel widening was significantly greater in the AL group than in the IF group at 2 years after primary ACLR. However, the clinical outcomes in the two groups were comparable at 2 years.
... Another potential limitation of this study might be a relatively short follow-up. According to literature, full integration of the graft after ACL reconstruction takes longer than 12 weeks [55,56], and an increase in bone tunnel diameter and BTE phenomenon might be observed even up to 12 months post-reconstruction [57,58]. Nevertheless, the aim of our study was to analyze the changes that occurred early after the reconstruction rather than the long-term outcomes of the procedure. ...
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The exact causes of failure of anterior cruciate ligament (ACL) reconstruction are still unknown. A key to successful ACL reconstruction is the prevention of bone tunnel enlargement (BTE). In this study, a new strategy to improve the outcome of ACL reconstruction was analyzed using a bioresorbable polylactide (PLA) stent as a catalyst for the healing process. The study included 24 sheep with 12 months of age. The animals were randomized to the PLA group (n = 16) and control group (n = 8), subjected to the ACL reconstruction with and without the implantation of the PLA tube, respectively. The sheep were sacrificed 6 or 12 weeks post-procedure, and their knee joints were evaluated by X-ray microcomputed tomography with a 50 μm resolution. While the analysis of tibial and femoral tunnel diameters and volumes demonstrated the presence of BTE in both groups, the enlargement was less evident in the PLA group. Also, the microstructural parameters of the bone adjacent to the tunnels tended to be better in the PLA group. This suggested that the implantation of a bioresorbable PLA tube might facilitate osteointegration of the tendon graft after the ACL reconstruction. The beneficial effects of the stent were likely associated with osteogenic and osteoconductive properties of polylactide.
... Tunnel enlargement after ACL reconstruction is a wellob served phenomenon with a reported incidence of 30.1% to 100% for femoral tunnels and 20.9% to 73.9% for tibial tunnels 3,17,18) . Though it does not cause any acute problem, revision cases with severely enlarged tunnels can be a challenge 19) . ...
Article
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Purpose: Tunnel widening following anterior cruciate ligament (ACL) reconstruction is commonly observed. Graft micromotion is an important contributing factor. Unlike fixed-loop devices that require a turning space, adjustable-loop devices fit the graft snugly in the tunnel. The purpose of this study is to compare tunnel widening between these devices. Our hypothesis is that the adjustable-loop device will create lesser tunnel widening. Materials and methods: Ninety-eight patients underwent ACL reconstruction from January 2013 to December 2014. An adjustable-loop device was used in 54 patients (group 1) and a fixed-loop device was used in 44 patients (group 2). Maximum tunnel widening at 1 year was measured by the L'Insalata's method. Functional outcome was measured at 2-year follow-up. Results: The mean widening was 4.37 mm (standard deviation [SD], 2.01) in group 1 and 4.09 mm (SD, 1.98) in group 2 (p=0.511). The average International Knee Documentation Committee score was 78.40 (SD, 9.99) in group 1 and 77.11 (SD, 12.31) in group 2 (p=0.563). The average Tegner-Lysholm score was 87.25 (SD, 3.97) in group 1 and 87.29 in group 2 (SD, 4.36) (p=0.987). There was no significant difference in tunnel widening and functional outcome between the groups. Conclusions: The adjustable-loop device did not decrease the amount of tunnel widening when compared to the fixed-loop device. There was no significant difference in outcome between the two fixation devices. Level of evidence: Level 3, Retrospective Cohort.
... Hence, a possible factor that can minimize tunnel widening is thought to be rigid fixation. Attaining rigid fixation is supposed to minimize elongation (bungee effect) and prevent failure at the graft fixation sites during the cyclical loading of the knee before the biological incorporation of the ACL graft [22,23]. Because Tight Rope RT, Bioscrew and Transfix, all are popular and well-established femoral-side fixation methods that provide stable fixation, we took up this comparative analysis to study the outcome. ...
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Purpose To evaluate femoral tunnel widening in young and active patients undergoing ACL reconstruction with quadrupled hamstring graft with fixation on tibial side performed with a Bioscrew while femoral fixation performed with either a Tight rope Reverse Threaded (RT) or Transfix or another Bioscrew using CT scan. Material and method A total of 100 consecutive patients underwent single-bundle ACL reconstruction from January 2008 to March 2012. Eighty-six out of these were available with us till the final follow-up. Only 20–40-year-old males with unilateral ACL rupture less than a year old, diagnosed clinically and confirmed radiologically by magnetic resonance imaging, were selected for the study. All patients were evaluated clinically as well as radiologically at follow-up of 2 weeks, 1 month, 3 months, 6 months, 1 year and every 6 months thereafter. CT scans were performed at 2 weeks, 6 months, and 1 year postoperatively. The data acquired at the second week were considered as baseline data and were used for comparison with the data acquired at 6 months and 1 year. Results The dilatation at the aperture was significantly more in the Tight rope RT group as compared to the other two groups (p value 0.019 and 0.021 for sagittal and coronal images, respectively). Conclusion There is no significant difference between the three different fixation modes in context of tunnel enlargement except with Tight rope RT device which leads to statistically significant dilatation at aperture. Future studies with longer follow-up are required to evaluate its clinical implications.
... Journal of Orthopaedic Surgery and Research (2022) 17:244 may improve tendon-to-bone healing (1,2) and it avoids damage to the graft during screw insertion (3,4). Furthermore, the insertion of interference screws leads to a significant initial enlargement of the bone tunnel at the time of the surgery and results in larger tibial tunnels after 2 years compared to extracortical fixation (5,6). Another technical issue that might contribute to a loss of pullout strength, when using interference screws for graft fixation, is screw divergence (7,8). ...
Article
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Background Cortical suspensory fixation (CSF) devices gain more and more popularity as a reliable alternative to interference screws for graft fixation in anterior cruciate ligament (ACL) reconstruction. Adjustable-loop fixation may be associated with increased anterior laxity and inferior clinical outcome. The purpose of the study was to compare anterior laxity and clinical outcome after minimally invasive all-inside ACL reconstruction using an adjustable-loop (AL) to a standard technique with a fixed-loop (FL) CSF device. Methods Patients who underwent primary single-bundle ACL reconstruction with a quadrupled hamstring autograft at a single institution between 2012 and 2016 were reviewed. In the AL group minimally invasive popliteal tendon harvesting was performed with an all-inside approach (femoral and tibial sockets). In the FL group a traditional anteromedial approach was used for tendon harvesting and a femoral socket and full tibial tunnel were drilled. An objective clinical assessment was performed with Telos x-rays and the International Knee Documentation Committee (IKDC) Objective Score. Patient-reported outcomes (PRO) included the IKDC Subjective Score, the Lysholm Knee Score, the Knee Injury and Osteoarthritis Score (KOOS) and the Tegner Activity Scale. Results A total of 67 patients were enrolled in this retrospective study with a mean follow-up of 4 (± 1.5) years. The groups were homogenous at baseline regarding age, gender, and the time to surgery. At follow-up, no statistically significant differences were found regarding anterior laxity (AL: 2.3 ± 3 mm vs. FL: 2.3 ± 2.6 mm, p = 0.981). PRO scores were comparable between the AL and FL groups (IKDC score, 84.8 vs. 88.8, p = 0.185; Lysholm 87.3 vs. 89.9, p = 0.380; KOOS 90.7 vs. 91.4, p = 0.720; Tegner 5.5 vs. 6.2, p = 0.085). The rate of saphenous nerve lesions was significantly lower in the AL group with popliteal harvesting of the tendon (8.3% vs. 35.5%, p = 0.014). Conclusion The use of an adjustable-loop device on the femoral and tibial side led to similar stability and clinical results compared to a fixed-loop device.
... We used the endo button as the femoral fixation device and interference screw as the tibial fixation device. Though there are concerns about the bungee effect of the graft while using the endo button causing movement of graft in the tunnel, tunnel widening and interference to graft incorporation, a recent study Buelow et al. (25) had reported tunnel widening also occurs with an interference screw. Tunnel widening is attributed to multiple factors rather than mechanical factors of the fixation device alone according to Ma et al and Wilson et al (26,27) . ...
... The clinical importance of BTE is not yet well understood. Despite research having been conducted on BTE, there is a lack of studies on the correlation between BTE and surgical success [13][14][15][16][17][18][19]. It is possible that BTE is an early sign of graft failure resulting in a future renewed lesion [9], as evaluated by radiographs and arthrometry. ...
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Purpose: The purpose was to determine the impact of the size of bone bruises (BBs) on bone tunnel enlargement (BTE) occurrence. Materials and methods: Twenty-four (24) patients who underwent anterior cruciate ligament reconstruction (ACLR) were included in this retrospective study. The measurements of BBs based on the initial MRI scan, bone tunnel size based on the control MRI scan, and the spatial determination of BB in relation to the bone tunnel location were evaluated. To analyze the relationship between BBs and BTE in homogeneous groups regarding the time from injury to ACLR (t(I-S)), the largest subgroup B (n = 15), in which t(I-S) was 31 to 60 days, was isolated for further investigation. Results: Based on subgroup B, a weak correlation (r = 0.33) existed between the BB volume and BTE size in the femur and tibia. Considering the relationship between the distance from the BB to the bone tunnel in the femur (f-l) and its enlargement (Δfd), there was a moderate and statistically significant (p < 0.05) negative correlation (r = −0.64). The correlation between those parameters was even stronger (r = −0.77) in subgroup B (time interval between injury and surgery ranged from 31 to 60 days). Conclusions: A retrospective analysis of MRI data in patients after ACL reconstruction surgery showed a relevant association between the distance from the BB to the bone tunnel and BTE in the femur. The relationship was not confirmed in the tibia.
Article
PurposeAnterior cruciate ligament (ACL) reconstruction is widely accepted as the first choice of treatment for ACL injury, but there is disagreement in the literature regarding the optimal femoral fixation method. This meta-analysis assesses the evidence surrounding three common femoral fixation methods: cortical button (CB), cross-pin (CP) and interference screws (IS).MethodsA systematic search was conducted in Medline, EMBASE and the Cochrane Library to identify studies with evidence level I or II that compared at least two femoral fixation methods with hamstring autograft for ACL reconstruction. Ten primary outcomes were collected. Risk of bias was assessed following the Cochrane Handbook for Systematic Reviews of Interventions. Standardized mean differences (SMD) were estimated using random-effects network meta-analysis in a Bayesian framework. Probability of ranking best (ProBest) and surface under the cumulative ranking curve (SUCRA) were used to rank all treatments. Funnel plots were used to identify publication bias and small-study effects.ResultsSixteen clinical trials were included for analysis out of 2536 retrieved studies. Bayesian network meta-analysis showed no significant differences among the three fixation methods for the ten primary outcome measures. Based on the 10 outcome measures, the IS, CB and CP had the highest ProBest in 5, 5 and 0 outcomes, and the highest SUCRA values in 5, 4 and 1 outcomes, respectively. No substantial inconsistency between direct and indirect evidence, or publication bias was detected in the outcomes.Conclusion There were no statistical differences in performance among the CP, CB and IS femoral fixation methods with hamstring autograft in ACL reconstruction, although the IS was more likely to perform better than CB and CP based on the analysis of outcome measures from the included studies.Level of evidence1.
Article
Importance There is significant controversy regarding the optimal femoral fixation method in anterior cruciate ligament (ACL) reconstruction. Given the importance of ACL reconstruction in patient return to sport and quality of life, it is imperative to identify the optimal method of femoral fixation. Objective The primary objective of this study is to identify the optimal method of femoral fixation in ACL reconstruction with soft tissue grafts. There are three main techniques for femoral-sided fixation in ACL reconstruction: suspensory extracortical buttons (EC), interference screws (IS) and transfemoral crosspins (TF). Previous primary studies have provided conflicting results regarding the superior method, and prior systematic reviews have failed to identify a difference; however, these analyses were only able to make comparisons between two of the treatments directly. This study employed a network meta-analysis technique to maximise sample size and statistical power, increasing the validity of its findings. Evidence review A network meta-analysis was conducted using results from 19 randomised controlled trials. Only studies with level I or II evidence, directly comparing two interventions in ACL soft tissue graft reconstruction, were included. Graft failure rates, International Knee Documentation Committee scores and KT-1000 knee arthrometer scores were the primary outcomes measured. Secondary outcomes included Lysholm, Tegner, Lachman and Pivot Shift scores. Findings An overall sample of 1372 patients was analysed. No statistically significant differences were detected among outcomes, except for the KT-1000 analysis which slightly favoured EC over IS and TF fixation (mean difference (MD)=−0.53 mm; 95% CI −0.07 to –0.98), and TF over IS fixation (MD=−0.41 mm; 95% CI −0.05 to –0.76). The clinical consequences of this difference are likely minimal. Conclusions Based on the results of this network meta-analysis, there is no clear statistically superior method of femoral fixation in soft tissue ACL reconstruction. Level of evidence Level II (systematic review of level I and II studies).
Article
Purpose: Anterior cruciate ligament reconstruction (ACLR) using a short, quadrupled semitendinosus (ST-4) autograft, fixed with an adjustable suspensory fixation (ASF), has several potential advantages. However, the construct is suspected to generate micromotion, tunnel widening and poor graft maturation. The aim of this study was to evaluate post-operative tibial tunnel expansion, graft maturation and clinical outcomes for this type of ACLR. Methods: One-hundred and forty-nine patients were reviewed at a minimum of 2 years following 4-ST ACLR, mean 25.6 ± 3.5 months [24-55], with clinical follow-up and MRI scans. Graft maturity of the intra-articular part of the graft and the tibial tunnel portion was assessed using Signal-to-Noise Quotient (SNQ) and Howell score. Tibial tunnel expansion, bone-graft contact and graft volume in the tibial tunnel were calculated from the MRI scans. Results: Mean tibial tunnel expansion was 13 ± 16.5% [12-122]. Mean SNQ for graft within the tibial tunnel was 3.8 ± 7.1 [ - 7.7 to 39] and 2.0 ± 3.5 [ - 14 to 17] for the intra-articular portion of the graft. The Howell score for graft within the tibial tunnel was 41% Grade I, 37% Grade 2, 20% Grade 3, 2% grade 4, and for the intra-articular part 61% Grade 1, 26% Grade 2, 13% Grade 3 and 1% Grade 4. The mean tibial tunnel bone-graft contact was 81 ± 23% [0-100] and mean graft volume was 80 ± 22% [0-100]. No correlation was found between tibial tunnel expansion and graft maturity assessed at both locations. Graft maturity was correlated with higher graft-bone contact and graft volume in the tibial tunnel (p < 0.05). Conclusions: ST-4 ACLR with ASF had low levels of tunnel enlargement at 2 years. No correlation was found between graft maturation and tibial tunnel expansion. Graft maturity was correlated with graft-bone contact and graft volume in the tibial tunnel. Level of evidence: Level III.
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Purpose: To study the effect of coating tendon grafts with mesenchymal stem cells (MSCs) on the rate and quality of graft osteointegration in anterior cruciate ligament (ACL) reconstruction. Type of study: Animal model. Methods: Bilateral ACL reconstructions using hamstring tendon autografts were performed on 48 adult rabbits. Grafts were coated with MSCs in a fibrin glue carrier in one limb, and fibrin glue only in the other. Assessment was done at 2, 4, and 8 weeks. Histologic analysis was carried out using standard and immunohistochemical stains. Biomechanical testing of force and stiffness during loading to ultimate failure was performed. Results: Control reconstructions showed mature scar tissue with some Sharpey's-like fibers spanning the tendon-bone interface at 8 weeks. The MSC-enhanced reconstructions had large areas of cartilage cells at the tendon-bone junction at 2 weeks. By 8 weeks, a mature zone of cartilage was seen gradually blending from bone into the tendon grafts. This zone stained strongly for type II collagen and showed histologic characteristics similar to normal rabbit ACL insertions. Biomechanically, there was no statistical difference between limbs at 2 and 4 weeks. At 8 weeks, the MSC-enhanced grafts had significantly higher failure load and stiffness. Conclusions: Coating of tendon grafts with MSCs results in healing by an intervening zone of cartilage resembling the chondral enthesis of normal ACL insertions rather than collagen fibers and scar tissue. MSC-enhanced ACL reconstructions perform significantly better than controls on biomechanical testing. Clinical relevance: Enhancement of tendon graft osteointegration with MSCs is a novel method offering the potential for more physiologic and biomechanically stronger ligament reconstructions.
Article
Bone tunnel–related complications are frequently encountered during revision anterior cruciate ligament reconstruction (ACLR). Issues with tunnel positioning, enlargement, containment, and hardware interference may complicate surgery and compromise outcomes. As a result, several strategies have emerged to address these issues and optimize results. However, a systematic, unified approach to tunnel pathology in revision ACLR is lacking. The purpose of this review is to highlight the current state of the literature on bone tunnel complications and, although extensive literature on the subject is lacking, present an updated approach to the evaluation and management of tunnel-related issues in revision ACLR.
Article
Objective: To evaluate the effects of two different femoral cortical suspension devices (fixation loop and adjustable loop) on tunnel widening and knee function in patients following anterior cruciate ligament reconstruction for 12 months. Methods: A total of 60 patients who had undergone anterior cruciate ligament reconstruction were included in this study. According to the length of the loop(n)[n= total length of loop-(total length of femoral tunnel-total length of coarse tunnel)] in the rough bone tunnel, the patients were divided into A (adjustable loop was 0 mm in the coarse bone tunnel), B (fixation loop was greater than 0 mm and less than or equal to 10 mm in the coarse bone tunnel) and C (fixation loop was greater than 10 mm in the coarse bone tunnel) groups, of which 11 cases were in group A, 27 cases in group B and 22 cases in group C. In the three-dimensional reconstruction of the knee joint with multi-slice spiral CT, the widening of the bone tunnel in the three groups was compared. At the same time, IKDC, Lysholm and Tegner scores of the patients in the three groups were compared. Results: There were differences in the widening degree of the femoral canal among groups A, B and C, and the median difference of the widening degree of the femoral tunnel 12 months and immediately after the surgery was A < B < C. The difference of femoral canal widening in group A was significantly different from that in groups B and C (P < 0.05).According to the linear regression the relationship between the difference of the width of the femoral canal and the change of the length (n) of the loop in the coarse canal, it was found that there was a linear relationship between the value of n and the difference of the width of the bone canal. With the increase of the value of n, the difference of the width of the bone canal gradually became larger. The median difference of the width of the middle and superior tunnel was negative, while the median difference of the width of the middle and inferior tunnel was positive. During the follow-up, we found that there were no statistical differences in IKDC, Lysholm and Tegner scores among the three groups one year after surgery (P > 0.05). Conclusion: Twelve months after surgery, compared with group B (fixed loop group) and group C (fixed loop group), group A (adjustable loop group) had less bone tunnel widening.In groups A, B and C, as the length of the loop in coarse bone tunnel gradually increased, the width of bone tunnel became more significant. At the end of 12 months follow-up after anterior cruciate ligament reconstruction, the medial and inferior femoral tunnel was significantly wider than immediately after surgery, and the medial and superior femoral tunnel had gradually begun to undergo tendon-bone healing. There was no significant difference in knee function scores among groups A, B, and C in the follow-up 12 months after surgery.
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Background The effect of demineralized bone matrix (DBM), bone marrow–derived mesenchymal stromal cells (BMSCs), and platelet-rich plasma (PRP) on bone tunnel healing in anterior cruciate ligament reconstruction (ACLR) has not been comparatively assessed. Hypothesis These orthobiologics would reduce tunnel widening, and the effects on tunnel diameter would be correlated with tunnel wall sclerosis. Study Design Controlled laboratory study. Methods A total of 20 sheep underwent unilateral ACLR using tendon allograft and outside-in interference screw fixation. The animals were randomized into 4 groups (n = 5 per group): Group 1 received 4mL of DBM paste, group 2 received 10 million BMSCs in fibrin sealant, group 3 received 12 mL of activated leukocyte-poor platelet-rich plasma, and group 4 (control) received no treatment. The sheep were euthanized after 12 weeks, and micro-computed tomography scans were performed. The femoral and tibial tunnels were divided into thirds (aperture, midportion, and exit), and the trabecular bone structure, bone mineral density (BMD), and tunnel diameter were measured. Tunnel sclerosis was defined by a higher bone volume in a 250-µm volume of interest compared with a 4-mm volume of interest surrounding the tunnel. Results Compared with the controls, the DBM group had a significantly higher bone volume fraction (bone volume/total volume [BV/TV]) (52.7% vs 31.8%; P = .020) and BMD (0.55 vs 0.47 g/cm ³ ; P = .008) at the femoral aperture and significantly higher BV/TV at femoral midportion (44.2% vs 32.9%; P = .038). There were no significant differences between the PRP and BMSC groups versus controls in terms of trabecular bone analysis or BMD. In the controls, widening at the femoral tunnel aperture was significantly greater than at the midportion (46.7 vs 41.7 mm ² ; P = .034). Sclerosis of the tunnel was common and most often seen at the femoral aperture. In the midportion of the femoral tunnel, BV/TV ( r = 0.52; P = .019) and trabecular number ( r S = 0.50; P = .024) were positively correlated with tunnel widening. Conclusion Only DBM led to a significant increase in bone volume, which was seen in the femoral tunnel aperture and midportion. No treatment significantly reduced bone tunnel widening. Tunnel sclerosis in the femoral tunnel midportion was correlated significantly with tunnel widening. Clinical Relevance DBM might have potential clinical use to enhance healing in the femoral tunnel after ACLR.
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Background The femoral cortical suspension device such as fixed loop devices (FLD) and adjustable-loop device (ALD) are used for ACLR technique in recent days. However, there was few studies of clinical and radiographic results for ACLR using ALD. This study was conducted to clarify the clinical and radiographic results, stability and bone tunnel enlargement after ACLR using a ToggleLoc with a zip loop as ALD. Methods 80 patients who had data available from the most recent follow-up at ≥2 years since ACLR were evaluated both clinical and radiographic results. They were divided into single bundle reconstruction group (SBR) and double bundle reconstruction group (DBR). Clinical scores were included subjective scores and objective scores at pre- and postoperatively 2 years. The subjective scores were the Cincinnati knee rating system, Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm score, Tegner activity score, Visual Analog Scale (VAS) and ACL-Return to Sport after Injury (RSI) scale. The objective scores were the isokinetic muscle strength, side-to-side difference in anterior instability and single hop test. In radiographical assessment, femoral and tibial tunnel enlargement was evaluated by three-dimensional computed tomography. Results In both SBR and DBR group, the postoperative subjective scores were significantly improved compared to the preoperative values, except for the Tegner activity score. Similarly, the side-to-side differences in muscle strength, anterior instability and single hop test were significantly improved after surgery. The changes in the femoral and tibial tunnel maximum cross section areas of SBR were 104.3 % ± 21.2 % and 89.2 % ± 15.2 %, respectively, at 2 years post-operatively. In DBR, in the femoral bone volume change of the antero medial (AM) and postero lateral (PL) bundle were 107.0 ± 3.5 % and 108.1 ± 3.3, and in the tibial bone volume change of AM and PL bundle were 90.6 ± 3.3 % and 87.0 ± 4.2 %. At the femoral site, the rate of tunnel enlargement increased for the first 12 months and then decreased through 24 months postoperatively. At the tibial site, by contrast, the rate of tunnel enlargement decreased consistently over the two-year postoperative follow-up. Conclusion This is the first study to include clinical data on ACLR using a ToggleLoc with a zip loop device. ACLR using these devices as ALDs resulted in good clinical outcomes and provided good stability of the knee with relatively little bone tunnel enlargement in both SBR and DBR group.
Article
Purpose: To investigate the tunnel enlargement rate and clinical function by comparing double-bundle anterior cruciate ligament reconstruction (ACLR) using different fixation devices. Methods: Patients receiving primary arthroscopic double-bundle ACLR were screened and divided into 2 groups on the basis of the method of graft fixation: bioabsorbable interference screw (BS) group and cortical button (CB) group. Bone tunnel size was assessed digitally using magnetic resonance imaging, which was performed a minimum of 2 years postoperatively. Clinical evaluations were performed using the Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee score, and KT-1000 arthrometer 2 years postoperatively. Results: Sixty patients receiving primary arthroscopic double-bundle ACLR were included. Overall, the BS group showed greater tunnel enlargement than the CB group, as well as a significantly increased rate of tunnel communication (P = .029). The average anteromedial tunnel enlargement rates for the BS and CB groups were 50% and 28%, respectively. The enlargement rate of the posterolateral (PL) femoral tunnel was similar in both groups. In the PL tibial tunnel, the CB group showed a significant increase in enlargement compared with the BS group (64% vs 45%, P = .0001). Both groups showed functional improvement in the Knee Injury and Osteoarthritis Outcome Score and International Knee Documentation Committee score. No significant difference in postoperative functional outcomes was found between the 2 groups. Conclusions: The BS group showed significantly greater tunnel enlargement in anteromedial tunnels and an increased tunnel communication rate compared with the CB group. On the other hand, the CB group showed greater tunnel enlargement in tibial PL tunnels. Tunnel communication was observed mostly on the tibial side in the BS patients. Equivalent clinical function outcomes were noted at 2 years after surgery in both groups of patients. Level of evidence: Level II, randomized controlled clinical trial.
Article
Background There is mixed opinion regarding the optimal femoral fixation method for hamstring tendon autograft in anterior cruciate ligament (ACL) reconstruction. Currently, no study exists showing a superior method of femoral fixation, and thus the topic has remained controversial. The purpose of this study is to network meta-analyze the randomized control trials comparing cortical-button (CB), cross-pin (CP) and interference screws (IS) for femoral fixation with hamstring tendon autograft in ACL reconstruction. Methods The literature review was conducted in accordance with the PRISMA guidelines. Randomized control trials comparing CB, CP and IS were included. Clinical outcomes were compared using a frequentist approach to network meta-analysis, with all statistical analysis performed using R, with a p-value <0.05 being considered statistically significant. Results There were 11 studies included comparing; 194 patients with CB to 201 patients with CP (6 studies), 48 patients with CB to 50 patients with IS (1 study), and 172 patients with CP to 162 patients with IS (5 studies). One study compared all three groups, including 48 patients with CB, 50 patients with IS, and 52 with CP. There was a mean follow-up time of 26.4 months. No statistically significant difference was found between the fixation methods when evaluating knee stability, functional outcomes, graft failures, or revision procedures. Conclusion Using a network meta-analysis, our study found that, there was no difference in failure rate, knee stability, functional outcomes or incidence of revision procedures between CB, CP or IS femoral fixation techniques of hamstring tendon autografts in ACL reconstruction. Level of evidence Level I, network meta-analysis of Level I studies.
Article
This study compared the clinical and radiological findings of nonanatomic transtibial (TT) technique with intraspongious fixation and anatomical anteromedial portal (AMP) technique with extracortical button implant in anterior cruciate ligament (ACL) reconstruction. A total of 54 patients with isolated ACL rupture were included in this prospective study. The patients who had the intraspongious fixation by nonanatomical TT technique were allocated to Group 1 (n ¼ 27). The patients with extracortical fixation by anatomical AMP technique were placed in Group 2 (n ¼ 27). The clinical scores of the patients were evaluated with the International Knee Documentation Committee Evaluation Form, Tegner activity score, and Lysholm II Functional Scoring. The tibial and femoral tunnels were evaluated with three-dimensional computed tomography. The kinematic examinations were performed with a Biodex System 3 Pro isokinetic dynamometer. There was no significant difference between the groups in terms of demographic data (p > 0.05). The postoperative clinical scores improved significantly in both the groups compared with the preoperative levels (p ¼ 0.001), but there was no significant difference in the postoperative clinical scores between the groups (p > 0.05). In the extension and flexion of 60 to 180 degrees/s, the peak torque and the peak torque/body weight values of the repaired knee to intact knee ratios showed significant differences in favor of Group 2 (p ¼ 0.001). In both the groups, no significant difference was found between the mean extent of the tunnel enlargement (p > 0.05). The mean tunnel height was significantly greater in Group 1 (45% AE 9.86 vs. 34.11% AE 10.0%) (p ¼ 0.001). When the localization of the tunnel enlargements (proximal-middle-distal) was examined, a significant difference was found between the groups (p ¼ 0.001). Although the AMP technique, which is a more anatomic reconstruction , had an advantage with regard to tunnel enlargement and the isokinetic muscle studies, there was no difference between the two techniques in terms of the clinical results.
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Background Hamstring tendons are widely used in anterior cruciate ligament reconstruction. Improvements in fixation materials have increased the success of the reconstruction procedures using this type of graft. The main advantage of the hamstring tendon autograft is the lower donor site morbidity associated with its harvesting. On the other hand, tunnel widening is reported more frequently with the use of hamstring tendon autograft compared to patellar or quadriceps tendons. The objective of the present study was to evaluate three different fixation techniques at a minimum of 2 years after Anterior Cruciate Ligament (ACL) reconstruction using gracilis and semitendinosus autograft. Methods Between February 2012 and March 2016, 112 ACL reconstructions using double looped semitendinosus and gracilis graft were performed. Patients were divided into 3 groups in a randomized fashion. 98 patients were followed up for 2 years. In the first group (43 patients), suspensory fixation using Retrobutton (Arthrex, Inc, Naples, Florida) was used. In the second group (30 patients), transcondylar graft fixation Bio-Transfix (Arthrex, Naples, Florida) was performed, and in the third group (25 patients), aperture fixation using AperFix (Cayenne Medical, Scottdale, Arizona, Biomet) was performed. Clinical evaluation was performed using the International Knee Documentation Committee (IKDC) form, Lysholm knee and Tegner activity level scores, as well as arthometer measurements. Tunnel enlargement and graft integrity were evaluated using Magnetic Resonance Imaging (MRI) at 6, 12 and 24 months. Results Ten patients were completely lost to follow up, and four had undergone a revision ACL reconstruction before the two-year follow up period, leaving 98 patients for analysis. No statistically significant differences between the three groups were noted other than that the first group tended to have more tunnel enlargement than the other two groups, especially at the femoral tunnel ( p =.026), but not at the tibial tunnel ( p >0.408). Our results showed that almost 90% of the patients in the three groups had functionally normal or near normal IKDC, Lysholm and Tegner scores. Conclusion The three different techniques yielded equal results as regards improved patient performance. The functional results as well as knee stability tests were not related with tunnel enlargement, at least in the short term.
Article
Purpose Revision ACL surgery may be complicated by tunnel malposition and/or tunnel widening and often requires a staged treatment approach that includes bone grafting, a period of several months to allow bone graft incorporation and then definitive revision ACL reconstruction. The purpose of this study was to evaluate the results of a single-staged ACL revision reconstruction technique using a cylindrical dowel bone graft for patients who have existing posteriorly placed and/or widened tibial tunnels in the tibia at a minimum of 2 years follow-up. Methods Between 2010 and 2014, patients undergoing single-stage revision ACL reconstruction with the described technique were prospectively enrolled and evaluated. At a minimum of 24 months, patients were evaluated by physical examination, multiple clinical outcome instruments including KOOS, Tegner and Lysholm, and preoperative and postoperative MRIs. Results At a mean of 35.1 months, 18 consecutive patients had no revision surgery and no subjective knee instability. There were statistically significant improvements in the Tegner (median 2, interquartile range 2.25; p < 0.01), Lysholm (20.0 ± 15.0; p < 0.01), KOOS symptoms scale (12.9 ± 11.8; p < 0.01), KOOS pain scale (15.4 ± 18.7; p < 0.01), KOOS ADL scale (13.5 ± 19.0; p < 0.01), KOOS sports scale (32.8 ± 26.4; p < 0.01), and KOOS QoL scale (18.1 ± 16.9; p < 0.01). Postoperative MRI demonstrated statistically significant anteriorization of the tibial tunnel and a statistically significant decrease in tunnel widening. Conclusion Revision ACL reconstruction utilizing a single-staged tibial tunnel grafting technique resulted in improved knee pain, function, and stability at a minimum of 24-month follow-up. Level of evidence IV.
Article
The purpose of this study is to determine whether the hamstring grafts are fully inserted into the femoral tunnel with the adjustable loop using immediate postoperative magnetic resonance imaging (MRI) after anterior cruciate ligament (ACL) reconstructions. A total of 62 consecutive patients underwent hamstring ACL reconstruction using an adjustable-loop cortical suspension device for the femoral fixation and the Intrafix sheath and screw for the tibial fixation. Multiplanar reformatted images of 3-T MRI scans were obtained at the 1st postoperative day before weight bearing is initiated in all patients to evaluate the gap (the tunnel–graft gap) between the top of the hamstring graft and top of the femoral tunnel. Postoperative MRI scans showed that the tunnel–graft gap was 1.5 ± 2.7 mm (range, 0–12 mm). In 43 (69.4%) patients, there was no gap between the top of the femoral tunnel and hamstring graft. In 19 (30.6%) patients, there was a gap between the tunnel and graft, and nine patients demonstrated a tunnel–graft gap greater than 5 mm. Immediate postoperative MRI scans demonstrated that an adjustable-loop cortical suspension device may not pull the hamstring graft completely into the femoral tunnel.
Article
Purpose: To report magnetic resonance imaging (MRI) findings and clinical outcomes after anterior cruciate ligament reconstruction using an adjustable-loop device (ALD) with retensioning and knot tying. Methods: The inclusion criteria were patients who underwent hamstring anterior cruciate ligament reconstruction using an ALD with retensioning and knot tying between May and December 2015 and were followed up for a minimum of 2 years. The exclusion criteria were patients with combined ligament injury, revision surgery, or reinjury after reconstruction. After initial tightening of the adjustable loop, retensioning and knot tying were performed and the graft was fixed at the tibia. Multiplanar reformatted images of 3-T MRI scans were obtained on the immediate postoperative day and at 6 months after surgery to measure the gap between the top of the graft and the top of the femoral tunnel (i.e., tunnel-graft gap). Differences in the tunnel-graft gap between the immediate postoperative day and 6 months after surgery (i.e., gap difference) were calculated and correlated with knee stability and functional outcomes. Results: Thirty-six patients were enrolled in this study. The mean tunnel-graft gap was 2.1 ± 2.8 mm on the immediate postoperative day and 4.6 ± 3.5 mm at 6 months after surgery (P < .001). The mean gap difference was 2.5 ± 2.0 mm. The mean KT-1000 measurement was 1.5 ± 2.2 mm, and mean Lysholm score and Tegner activity scale score were 93.6 ± 5.5 and 5.6 ± 1.5, respectively. The gap difference correlated negatively with the follow-up Lysholm score (P = .004); however, knee stability and the Tegner activity scale score were not correlated. Conclusions: Although the ALD was secured by retensioning and knot tying, MRI showed that the graft was not fully inserted in some patients and the tunnel-graft gap increased at 6 months' follow-up. The increase in the tunnel-graft gap did not correlate with knee stability or the Tegner activity scale score but correlated negatively with the Lysholm score. Level of evidence: Level IV, therapeutic case series.
Article
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Purpose To improve technique of cortical fixation of quadrupled semitendinosus autograft in anterior cruciate ligament (ACL) reconstruction providing a tight contact of the tendon and bone inside the tunnels. Material and methods Application of the technique offered earlier for preparation and placement of quadrupled semitendinosus autograft in ACL reconstruction for a maximal tendon-bone contact is reviewed. The technique uses cortical buttons for semitendinosus graft fixation. Proximal and distal ends of the graft are corrugated at placement, thus increasing the diameter and providing additional fixation inside the bone tunnels. The modified technique employs same corrugated sutures with an easier placement practice. Potential fixation tightness in the tunnels is assessed by an increase in the diameter at both ends of the prepared graft while tightening corrugated sutures. Six semitendinosus tendons of 3 cadavers were used for testing. Results Diameters of the proximal and distal ends of the graft prepared with modified technique increased by 1.33 ± 0.52 mm and 1.5 ± 0.55 mm, respectively, at tightening the corrugated sutures. The ends of the corrugated sutures were tightened with a force of 50 N with a tension of 80 N applied to the graft. Elastic deformation was observed at 364.83 ± 69.16 N during the tensile test for the graft prepared with earlier technique and cortical fixation thread with the focus on the strength of transverse threads. The modified technique ensured a reliable construct being comparable with that provided by all-inside technique (760 N) by removing the weak link. Tendon graft preparation time reduced by 30 %. Conclusion Modification of the earlier described technique for preparation and placement of quadrupled semitendinosus autograft facilitated tight contact of the tendon and bone inside the tunnels, easier placement practice and improved strength characteristics of the prepared graft.
Article
PurposeBone tunnel widening following anterior cruciate ligament reconstruction (ACLR) is well documented, although the aetiology and clinical significance of this phenomenon remain unclear. At mid-term follow-up, a greater prevalence of tunnel enlargement has been reported with the use of hamstring (HS) grafts. However, there are paucity of data on what happens in the longer term. The aim of this study was to assess the change in femoral and tibial tunnel dimensions 15 years after four-strand HS ACLR.Methods This is a retrospective review of 15 patients who underwent arthroscopic ACLR using HS autograft tendon and were followed up radiographically at 4 months, 2 years and 15 years. Suspensory fixation was used for both ends of the graft. The diameters of the bone tunnels on posteroanterior (PA) and lateral radiographs were measured using digital callipers. Repeated measures analysis of variance (ANOVA) was used to examine change in tunnel width over time.ResultsRadiographic tunnel width did not significantly change between 4 months and 2 years. However, a significant decrease in width was found for both the femoral and tibial tunnels between the 2- and 15-year follow-up (P < 0.01): the femoral tunnel decreased by 50% and 51% in the PA and lateral views, respectively; the tibial tunnel decreased by 77% and 91% in the PA and lateral views respectively. There was no significant correlation between femoral or tibial tunnel width and flexion and extension deficits or with side to side differences in anterior tibial laxity at 15 years.Conclusions This radiographic follow-up study of bone tunnel widening following HS ACLR with suspensory fixation demonstrated that tunnel width did not increase beyond 4 months and in fact had decreased significantly at long-term (15 years) follow-up. There was no correlation between tunnel width changes and clinical assessment of flexion and extension deficits or with side-to-side anterior knee laxity at 15-years.Level of evidenceIV
Article
Introduction Among the postoperative phenomenon of ACL reconstruction, tunnel enlargement has been reported consistently, regardless of the technique used. It could be clinically relevant in post operative follow up and revision surgery. This study evaluated the magnitude of tibial and femoral bone tunnels enlargement after arthroscopic double-bundle anterior cruciate ligament (ACL) reconstruction by the Computed Tomography Scan. Methods Forty patients undergoing arthroscopic double-bundle ACL reconstruction using multistranded hamstring graft, were included in the study. CT scan was performed on second postoperative day and at follow-up of 6 month. Tunnels were evaluated by digitally measuring the widths, perpendicular to the long axis of the anteromedial (AM) and posterolateral (PL) tunnels, on an oblique coronal, saggital and axial plane at 3 levels: aperture, midway, and suspension point. Bony bridge thickness at aperture and minimum distance between two tunnels to anticipate communication was also computed. Results Femoral tunnel measurement showed statistically significant enlargement at aperture and midway. At the aperture, enlargement of AM and PL tunnel was 21.95% and 26.16% whereas at midway, enlargement was 20.05% and 24.5%. At the suspension point, enlargement was 3.97% and 7.1%. On tibial side, order of significant enlargement was midway of AM = 21.16% and PL = 31.78% followed by aperture of AM = 18.9% and PL = 28.84% and finally suspension point of AM = 17.84% and PL = 25.21%. Average bony bridge thickness at femoral and tibial aperture was 0.291 ± 0.059 and 0.231 ± 0.105 cm respectively with 10% of the patients showed merging of tunnels at aperture. Conclusion CT scan is an effective way to determine the tunnel position and enlargement after ACL reconstruction. There is a significant widening of femoral and tibial tunnels at 6 months follow-up of arthroscopic double bundle anterior cruciate ligament reconstruction. Tunnel widening could be a serious problem after double-bundle ACL reconstruction.
Article
Background Graft healing within the femoral tunnel after anterior cruciate ligament reconstruction (ACLR) using suspensory fixation could be reflected in graft maturation and tunnel morphological changes. However, the correlation between graft maturation and femoral tunnel changes remains unclear. Purpose To quantitatively evaluate femoral tunnel morphological changes and graft maturation and to analyze their correlation after ACLR using femoral cortical suspension. Study Design Case series; Level of evidence, 4. Methods Patients who underwent single-bundle ACLR with a hamstring tendon autograft using femoral cortical suspension were included. Preoperative and postoperative (at 6, 12, and 24 months) knee function were evaluated using KT-1000 arthrometer testing, the Lysholm knee scoring scale, and the International Knee Documentation Committee (IKDC) questionnaire. At 1 day, 6 months, 12 months, and 24 months after ACLR, 3-dimensional magnetic resonance imaging was performed to observe the morphology of the femoral tunnel and to evaluate graft maturation using the graft signal/noise quotient (SNQ). The Pearson product moment correlation coefficients ( r) of femoral tunnel radii versus clinical outcomes and graft SNQs at last follow-up were analyzed. Results A total of 22 patients completed full follow-up. KT-1000 arthrometer, Lysholm, and IKDC scores improved over time postoperatively, but no significant improvement was seen after 12 months ( P < .05). The radius of the tunnel containing the graft and the SNQs of the femoral intraosseous graft and intra-articular graft were the highest at 6 months, and they decreased by 24 months but remained higher than their 1-day postoperative values ( P < .05). Expansion mainly occurred at the anteroinferior wall of the femoral tunnel. The tunnel aperture radius was positively correlated with SNQs of the intraosseous graft ( r = 0.591; P < .05) and intra-articular graft ( r = 0.359; P < .05) but not with clinical outcomes. Conclusion After ACLR using suspensory fixation, morphological changes of the femoral tunnel were mainly observed in the part of the tunnel containing the graft, which expanded at 6 months and reduced by 24 months. Expansion mainly occurred at the anteroinferior wall of the femoral tunnel. Femoral tunnel expansion was correlated with inferior graft maturation but not with clinical outcomes.
Article
Purpose To compare the efficacy and safety of individual devices for femoral and tibial graft fixation respectively in anterior cruciate ligament (ACL) reconstruction (ACLR). Methods PubMed, Embase, Cochrane Library, and Web of Science were searched from inception to December 12, 2018. Randomized controlled trials (RCTs) comparing individual devices for ACL graft fixation were included. Bayesian network meta-analysis was performed to assess the efficacy profile, i.e., Lysholm score, International Knee Documentation Committee (IKDC) category, laxity, range of motion and Tegner score. Incidence of infection, effusion and graft rupture for each device was reported. Results 57 RCTs involving 4,304 patients aged 23.8-40.9 were included. Female proportion ranged 0-100%. Length of follow-up ranged 6-144 months. For 13 studied femoral fixation devices, no device was significantly different from others regarding Lysholm score, IKDC category, range of motion, and Tegner score. Bioabsorbable interference screw (standardized mean difference=1.3, 95% credible intervals:0.0-2.5) showed higher laxity than EndoPearl at borderline level of statistical significance, but the difference varied substantially within multiple sensitivity analyses. Infection (2.0%) was most commonly-seen in EndoPearl, while bone mulch screw had the highest incidence of effusion (5.5%) and graft rupture (5.5%). For 9 studied tibial fixation devices, no significant difference was observed in the aforementioned efficacy measurements. Bioabsorbable interference screw with staples had the highest incidence of infection (11.1%) and effusion (15.6%), while graft rupture was most commonly-seen in bone plug (4.0%). Conclusions Graft fixation devices in ACLR share a similar efficacy profile in terms of Lysholm score, IKDC category, range of motion and Tegner score, but not laxity. On the other hand, safety profile seems to vary among different devices. These findings can support surgeons, alongside their experience, preference and the relative cost of each device, in delivering an individualized plan for an optimal operation.
Article
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Objective To compare the clinical effectiveness of cortical button (CB), cross-pin (CP) and compression with interference screws (IS) fixation techniques in anterior cruciate ligament (ACL) reconstruction using hamstring graft. Methods Studies were systematically retrieved from PubMed, Embase, Cochrane Library and Web of Science up to May 20, 2021. Primary outcomes were KT-1000 assessment, International Knee Documentation Committee (IKDC) score A or B, Lachman’s test, pivot-shift test, visual analogue scale (VAS) score, Lysholm score, Tegner score, and Cincinnati Knee Score. Secondary outcomes included reconstruction failures and synovitis. League tables, rank probabilities and forest plots were drawn for efficacy comparison. Results Twenty-six controlled clinical trials (CCTs) with 1,824 patients undergoing ACL reconstruction with hamstring graft were included. No significant differences were found among CB, CP and IS fixation methods regarding the 10 outcomes. For KT-1000 assessment, IKDC score A or B, Lachman’s test, VAS score and pivot-shift test, CP had the greatest probability of becoming the best method, and IS may be the suboptimal method in 4 out of these 5 outcomes except pivot-shift test. Conclusions CP, CB and IS fixations have comparable clinical performance, while CP fixation is most likely to be the optimum fixation technique for hamstring graft in ACL reconstruction. Future larger-sample studies of high quality comparing these techniques in more clinical outcomes are required.
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This study determined that knee extension (range, -30° to 2°) and the slope of the intercondylar roof (range, 26° to 46°) vary widely between knees in both men and women. We found a weak relationship between knee extension and the slope of the intercondylar roof (r ² = 0.207); therefore, roof angle cannot be predicted by clinically measuring knee extension. Clinical relevance: A knee with a given degree of ex tension can have a variety of different slopes to the in tercondylar roof. Knees with the combination of hyper extension and a vertically oriented slope to the intercondylar roof are "unforgiving" because they re quire a more posterior position for the tibial tunnel to avoid roof impingement and an extensive roofplasty. If the surgical objective is to minimize the extent of the roofplasty and avoid roof impingement, then consider ation should be given to customizing the placement of the tibial tunnel to account for variability in knee exten sion and roof angle when reconstructing the anterior cruciate ligament. Studies have shown that isometric graft placement can be achieved with this surgical approach.
Article
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We report a prospective series evaluating the incidence and degree of tunnel widening in a well-matched series of patients receiving a hamstring or patella tendon graft for anterior cruciate ligament (ACL) deficiency. We correlated tunnel widening with clinical factors, knee scores, KT-1000 and isokinetic muscle strength to determine the clinical significance of this finding. Seventy-three patients at least 12 months post-ACL reconstruction were evaluated. Thirty-eight patients had received a doubled semitendinous and gracilis graft and 35 a bone-patella tendon-bone graft. All patients underwent a similar endoscopic procedure and accelerated postoperative rehabilitation. Tunnel widening was determined using standardized anteroposterior (AP) and lateral X-rays adjusted for magnification. A limited series of MRIs was performed to validate these measurements. There was a significant difference in the degree of tunnel widening between the two groups. The mean increase in femoral tunnel area in the hamstring group was 100.4% compared with a decrease of 25% in the patella tendon group (P = < 0.0001). In the tibial tunnel the mean increase in the hamstring group was 73.9% compared with a decrease of 2.1% in the patella tendon group (P = < 0.0001). The MRIs validated the plain film measurements. Tunnel widening did not correlate with the clinical findings, knee scores, KT-1000 or isokinetic muscle strength. Tunnel widening is marked in the hamstring group. Tunnel widening does not correlate with instability or a poor clinical outcome in the short term. The long-term implications of this finding are still to be determined.
Article
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Radiographic tibial and femoral bone tunnel enlargement has been demonstrated following anterior cruciate ligament (ACL) reconstruction. This study investigated whether bone tunnel enlargement differs between four-strand hamstring (HS) and patellar tendon (PT) ACL reconstructions over the course of a 2-year follow-up. Patients undergoing primary ACL reconstruction (n = 65) were randomised to receive either a PT or HS autograft. Femoral fixation in both groups was by means of an Endobutton. On the tibial side the PT grafts were fixed using a metallic interference screw, and the HS tendons by sutures tied to a fixation post. The PT grafts were inserted such that the proximal end of the distal bone block was within 10 mm of the tibial articular surface, resulting in a portion of free patellar tendon in the femoral tunnel immediately proximal to the articular surface. Patients were reviewed after 4 months and 1 and 2 years. Tunnel enlargement was determined by measuring the widths of the femoral and tibial tunnels with a digital caliper in both lateral and anteroposterior radiographs. Because of the presence of the interference screw and the proximity of the bone block to the tibial articular surface, the tibial tunnel could not be reliably measured in the PT group. Measurements were corrected for magnification, and changes in tunnel width were recorded relative to the diameters drilled at surgery. Standard clinical measures were also noted. In 32% of patients in the PT group there was femoral tunnel obliteration from 4 months onwards. For the other patients there was a significantly greater increase in femoral tunnel width in the HS group than in the PT group at each follow-up, but no significant change with time. There was also a marked increase in tibial tunnel width in the HS group at 4 months but not thereafter. There was no relationship between tunnel enlargement and clinical measurements. Although tunnel enlargement is more common and greater with HS grafts, it does not appear to affect the clinical outcome in the first 2 postoperative years. Femoral suspensory fixation does not in itself appear to be the principal cause of femoral tunnel enlargement, at least for PT grafts.
Article
Instrumented anterior/posterior laxity measurements were performed on 138 patients evaluated within 2 weeks of injury with their first traumatic knee hemar throsis. All patients were tested with the MEDmetric Arthrometer model KT-1000 in a knee injury clinic. Seventy-five of the patients had knee arthroscopy. Thirty-three had arthrometer laxity tests under anes thesia. Eighty-seven percent of patients arthroscoped had anterior cruciate ligament (ACL) tears and 41 % had meniscus tears. One hundred twenty normal subjects were tested to establish normal anterior laxity values. Three tests were used to evaluate anterior laxity: anterior displacement between a 15 and 20 pound force (compliance index), anterior displacement with a 20 pound force, and an terior displacement with a high manually applied force. Displacement measurements in normal subjects re vealed a wide range of normal laxity with a small right knee-left knee difference. For example, the 20 pound anterior displacement range was 3 to 13.5 mm with a right knee-left knee difference (mean ± SD, 0.8 ± 0.7 mm). Eighty-eight percent of the normals had a right- left difference of less than 2 mm. In the 53 patients arthroscoped who had complete ACL tears, the anterior laxity measurements performed in the clinic were suggestive or diagnostic of pathologic anterior laxity in 50 patients.
Article
Approximately 44% of patients develop osteoarthritis (OA) following rupture of the anterior cruciate ligament (ACL) if the injury is left unrepaired. Restoring knee stability through reconstruction, while providing symptomatic relief, has not been shown to reduce the incidence of degenerative changes. In fact, recent studies have shown that 50%-60% of ACL-reconstructed patients go on to develop degenerative changes or frank osteoarthritis. In light of these data, our group suggests that the cause of post-traumatic osteoarthritis is not biomechanical but biochemical. To test this hypothesis, we measured levels of nine cytokines which are important in modulating physiological and pathophysiological metabolism of cartilage in knee joint synovial fluid following ACL rupture. Our patient population contained both acute and chronic ACL ruptures. A total of 84 samples were collected and analyzed by enzyme-linked immunosorbent assay. On the basis of the data collected, we were able to identify subgroups of patients who, on the basis of their synovial fluid cytokine profile, may be at greater or lesser risk of developing post-traumatic OA. In general, patients displayed concentrations of interleukin-1 alpha (IL-1 alpha), basic fibroblastic growth factor (bFGF), transforming growth factor-beta (TGF-beta), granulocyte/macrophage-colony stimulating factor (GM-CSF), IL-6, and IL-8 that we interpreted as being consistent with an inflammatory reaction. Of great interest is the fact that the levels of these cytokines were very similar in patients 4 weeks after injury and in chronic patients, leading us to hypothesize that a chronic smoldering inflammatory reaction persists after resolution of the acute effusion.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Radiographic increase in the size of tibial and femoral tunnels has been observed. This retrospective study compared tibial tunnel diameter in 56 autograft and 87 allograft patellar tendon bone-tendon-bone anterior cruciate ligament replacements whose observed tunnel changes were correlated with clinical results at 1 year postoperatively. Tibial tunnel sclerotic margins were measured approximately 1 cm below the joint line. Exact tunnel dimension was calculated by using a magnification factor determined by the interference screw of known diameter within the same tunnel. Average allograft tunnel enlargement was 1.2 mm (-2.5 to 6.0) compared with the autograft tunnel enlargement of 0.26 mm (-2.5 to 2.7); the difference was significant (P > 0.0002). No significant difference was seen in KT-1000 arthrometer measurements between autograft or allograft groups, and no correlation was seen between increased tunnel size and clinical outcome as determined by the modified Hughston knee evaluation system. Tunnel measurement reproducibility was confirmed by independent repeated measurements. The significance of this tunnel enlargement is unknown and does not appear to adversely affect clinical outcome of allograft utilization. Possible explanations include an immune response with resorption, stress shielding proximal to the interference screw resulting in resorption, or an inflammatory response by synovium in the tunnel.
Article
Thirty-five patients had reconstruction of the anterior cruciate ligament with intraarticular fresh-frozen Achilles tendon allograft and extraarticular tibial band tenodesis. Patients were followed 2 to 4 years (mean, 2.5). Evaluation included clinical and functional examinations, measurement of tibiofemoral displacement, and anteroposterior and lateral radiographs. Clinical results were considered satisfactory in 85% of the patients; 16 had arthroscopic examination after the allograft; allograft biopsies in 9 at this time showed cellular and vascular tissue without evidence of immune reaction. Clinical, arthroscopic, and biopsy results were favorable, but radiologic results were not. In most patients there was a significant size increase in femoral and tibial bone tunnels, as measured from radiographs. In the 6 most extreme cases, bone tunnels measured 20 mm or more in diameter, twice the initial size. Etiology and clinical significance of these bone tunnel changes remain unknown. Enlargement appears to occur early after operation; it stabilizes within 2 years. No statistical correlation was seen between tunnel enlargement and results of clinical and functional examinations; nevertheless, unexplained tunnel enlargement is cause for concern, and allograft replacement of the anterior cruciate ligament with fresh-frozen Achilles tendon allograft should be considered a salvage procedure.
Article
This retrospective study was designed to evaluate changes in the diameter of the tibial tunnel over time following the reconstruction of the anterior cruciate ligament (ACL) with a bone-patellar tendon-bone autograft in 44 patients. The changes in the geometry of the bone tunnels were measured radiographically during the immediate postoperative period and at time intervals between 3 and 36 months after surgery. The dimensions at 1 year were correlated with the 1-year clinical results. The distance between the sclerotic margins of the tibial tunnel was measured at the distal tunnel exit on the medial tibial cortex, in the middle of the tunnel, and proximally at the level of the joint line. The dimensions were calculated by using a magnification factor determined by reference to the interference screw of known diameter located within the tunnel. The position of the centre of the tibial tunnel with regard to Blumensaat's line was also measured. The average tunnel diameter at the proximal tibial exit increased from 12 +/- 1.9 mm (mean +/- standard deviation) postoperatively to 14 +/- 2.2 mm at 3 months. The average proximal tunnel diameter did not significantly change from 3 months to 2 years, and then decreased to 13 +/- 2.4 mm at 3 years. At 1 year, most of the patterns of osteolysis were of the cone type (57%), followed by the cavity type (40%) and line type (3%). The degree of osteolysis was not related to the tibial tunnel position with respect to Blumensaat's line. There was no correlation between the changes in tunnel diameter and either the IKDC score or the residual joint laxity measured by a KT-100 arthrometer. The aetiology of tunnel enlargement is currently unknown. Possible factors responsible for bone resorption include micromotion of the graft relative to the tunnel wall, leading to an inflammatory response in the tunnel, or stress shielding of the tunnel wall proximal to the interference screw.
Article
Despite its current popularity and relative success, endoscopic reconstruction of the anterior cruciate ligament (ACL) using a bone-patellar tendon-bone (BPTB) graft has not yet been perfected. Using a recently developed robotic/UFS testing system, we assessed the overall stability of porcine knees following ACL reconstruction with different sites of tibial graft fixation--proximal, central, and distal. Testing of the intact knee was performed first to determine the normal anterior-posterior (A-P) displacements and in situ forces of the ACL under 110 N of anterior tibial loading of 30 degrees, 60 degrees, and 90 degrees of knee flexion. The knee was then reconstructed with a BPTB autograft, and the distal end of the graft was fixed sequentially at three different locations in each specimen--proximal, central, distal. A-P testing was repeated for each fixation site, and the resulting knee kinematics and the in situ forces of the grafts were compared to the intact case. The site of tibial fixation was demonstrated to have a significant effect on the resulting anterior displacement and internal rotation of the tibia as well as the in situ forces of the graft. Proximal fixation produced the most stable knee (A-P displacements reduced to 120% of intact at 30 degrees and 170% at 90 degrees), becoming significantly less stable with more distal fixation. These results suggest that proximal graft fixation may provide the most acute stability of the reconstructed knee.
Article
Restoring knee stability through reconstruction, while providing symptomatic relief, has not been shown to decrease the incidence of degenerative changes after rupture of the anterior cruciate ligament. This suggests that posttraumatic osteoarthritis may not be purely biomechanical in origin, but also biochemical. To test this, we measured the levels of seven cytokine modulators of cartilage metabolism in knee joint synovial fluid after anterior cruciate ligament rupture. We also measured keratan sulfate, a product of articular cartilage catabolism. The sample population consisted of patients with uninjured knee joints (N = 10), and patients with acute (N = 60), subacute (N = 18), and chronic (N = 8) anterior cruciate ligament-deficient knees. Synovial fluid samples were analyzed by enzyme-linked immunosorbent assays. Normal synovial fluids contained high levels of the interleukin-1 receptor antagonist but low concentrations of other cytokines. Immediately after ligament rupture there were large increases in interleukins 6 and 8, tumor necrosis factor alpha, and keratan sulfate. Interleukin-1 levels remained low throughout the course. As the injury became subacute and then chronic, interleukin-6, tumor necrosis factor-alpha, and keratan sulfate levels fell but remained considerably elevated 3 months after injury. Concentrations of interleukin-1Ra fell dramatically. Granulocyte-macrophage colony-stimulating factor concentrations were normal acutely and subacutely but by 3 months after injury were elevated 10-fold. Our data reveal a persistent and evolving disturbance in cytokine and keratan sulfate profiles within the anterior cruciate ligament-deficient knee, suggesting an important biochemical dimension to the development of osteoarthritis there.
Article
Thirty patients having had anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) autograft and thirty patients having had ACL reconstruction with hamstring (HS) autograft were enrolled. All procedures were performed using an endoscopic technique with identical postoperative rehabilitation, such that the only variable was the type of graft and its fixation. Lateral and 45 degrees posteroanterior (PA) weightbearing radiographs were performed in each patient at 6-12 (mean 9) months postoperatively in the HS group and 9-22 (mean 13) months postoperatively in the PT group. The sclerotic margins of the tunnel were measured at the widest dimension of the tunnel by a single observer and were compared with the initially drilled tunnel size after correction for radiographic magnification. For the BPTB group, all bone plugs appeared to be incorporated radiographically. On the femoral side, the bone plug was incorporated at the roof of the intercondylar notch, such that no tunnel measurement could be made. Well-defined sclerotic margins were always present at the tibial and femoral tunnels for the HS group and at the tibial tunnel for the BPTB group. The mean percentage increase in tunnel size in the PA view was 9.7%+/-14.7% for the BPTB tibial tunnel, 20.9%+/-13.4% for the HS tibial tunnel, and 30.2%+/-17.2% for the HS femoral tunnel. The mean percentage increase in tunnel size in the lateral view was 14.4%+/-16.1% for the BPTB tibial tunnel, 25.5%+/-16.7% for the HS tibial tunnel, and 28.1%+/-14.7% for the HS femoral tunnel. The difference in HS and BPTB tibial tunnel expansion on both the PA and lateral views was statistically significant (P = 0.003 and P = 0.01, respectively). Inter-observer variability was excellent with an intra-class correlation coefficient of 0.92. Tunnel expansion was significantly greater following ACL reconstruction using HS autografts than in those using BPTB autografts. The points of fixation for the HS grafts are at a greater distance from the normal insertion site and biomechanical point of action of the ACL than the points of fixation for BPTB grafts. We believe that this greater distance creates a potentially larger force moment during graft cycling which may lead to greater expansion of bone tunnels.
Article
Radiographic enlargement of bone tunnels following anterior cruciate ligament (ACL) reconstruction has been recently introduced in the literature; however, the etiology and clinical relevance of this phenomenon remain unclear. While early reports suggested that bone tunnel enlargement is mainly the result of an immune response to allograft tissue, more recent studies imply that other biological as well as mechanical factors play a more important role. Biological factors associated with tunnel enlargement include foreign-body immune response (against allografts), non-specific inflammatory response (as in osteolysis around total joint implants), cell necrosis due to toxic products in the tunnel (ethylene oxide, metal), and heat necrosis as a response to drilling (natural course). Mechanical factors contributing to tunnel enlargement include stress deprivation of bone within the tunnel wall, graft-tunnel motion, improper tunnel placement, and aggressive rehabilitation. Graft-tunnel motion refers to longitudinal and transverse motion of the graft within the bone tunnel and can occur with various graft types and fixation techniques. Aggressive rehabilitation programmes may contribute to tunnel enlargement as the graft-bone interface is subjected to early stress before biological incorporation is complete. Further basic research is required to verify the effect of the various proposed factors on the etiology of bone tunnel enlargement. We recommend that routine follow-up examinations after ACL reconstruction should include the measurement of bone tunnel size in order to contribute to a better understanding of the incidence, time course, and clinical relevance of this phenomenon. Improved and more anatomical surgical fixation techniques may be useful for the prevention of bone tunnel enlargement.
Article
The purpose of this study was to prospectively evaluate changes in the tibial bone tunnel following endoscopic anterior cruciate ligament (ACL) reconstruction with patellar tendon autograft. We used computed tomography (CT) sequentially to monitor the time course of these changes over a 2-year period and correlated the results to clinical outcome and instrumented laxity measurements. Case series. Thirty-four patients (11 women, 23 men; mean age, 26.4 +/- 4.5 years) who underwent endoscopic patellar tendon ACL reconstruction, were evaluated clinically according to IKDC, Lysholm, and Tegner scores as well as with respect to changes in tibial tunnel morphology over a 2-year period. Subsequent CT scans were performed at 1 and 6 weeks and at 3, 6, 12, and 24 months postoperatively. The tibial bone tunnel was measured in the sagittal and coronal planes at 5 different levels (L1 to L5). The diameters of the tibial tunnel increased an average overall by 30.6% in the sagittal plane and 16.4% in the coronal plane within 2 years. The enlargement was significantly higher (P <.05) in the mid portion of the tunnel (L 2/3: 44.0% and 47.9% in the sagittal and 29.8% and 29.9% in the coronal plane, respectively), which resulted in a uniform cavity-type appearance. The percentage of change in tunnel size was significantly higher (P <.05) within the first 6 weeks following surgery compared with all other time intervals. No correlation between the amount of tunnel enlargement and the clinical results or between tunnel enlargement and KT-1000 measurements could be detected. Endoscopic ACL reconstruction is associated with tibial tunnel enlargement, which is already present within weeks following surgery. However, no negative effects on the clinical results were found over a 24-month period in our study population.