Femoral tunnel placement in anterior cruciate ligament reconstruction: rationale of the two incision technique

Does medial patellofemoral ligament reconstruction result in femoral tunnel enlargement? A systematic review

BACKGROUND

Medial patellofemoral ligament (MPFL) reconstruction is a common surgical procedure for treating patellar instability. The primary aim of this systematic review was to determine whether MPFL reconstruction (MPFLR) leads to femoral tunnel enlargement (FTE). The secondary aims were to explore the clinical effects and risk factors of FTE. Electronic databases (MEDLINE, Global Health, Embase), currently registered studies, conference proceedings and the reference lists of included studies were searched independently by three reviewers. There were no constraints based on language or publication status. Study quality assessment was conducted. 3824 records were screened in the initial search. Seven studies satisfied the inclusion criteria, evaluating 380 knees in 365 patients. Rates of FTE following MPFLR ranged from 38.7 to 77.1%. Five low quality studies reported FTE did not lead to detrimental clinical outcomes as assessed with the Tegner, Kujala, IKDC, and Lysholm scores. There is conflicting evidence regarding change in femoral tunnel width over time. Three studies (of which two had a high risk of bias) reported age, BMI, presence of trochlear dysplasia and tibial tubercle-tibial groove distance did not differ between patients with and without FTE, suggesting these are not risk factors for FTE.

CONCLUSION

FTE is a common postoperative event following MPFLR. It does not predispose poor clinical outcomes. Current evidence lacks the ability to identify its risk factors. The reliability of any conclusions drawn is hindered by the low level of evidence of the studies included in this review. Larger prospective studies with long-term follow up are required to reliably ascertain the clinical effects of FTE.

Effect of Surgical Design Variations on the Knee Contact Behavior during Anterior Cruciate Ligament Reconstruction

In this study, we aimed to develop an in-silico synthesis of the effect of critical surgical design parameters on articular contact behavior for a bone-patellar-tendon-bone anterior cruciate ligament reconstruction (ACL-R) surgery. A previously developed finite element model of the knee joint consisting of all relevant soft tissues was employed. The knee model was further updated with additional features to develop the parametric FE model of the biomechanical experiments that depicted the ACL-R surgery. The parametricity was created involving femoral tunnel architecture (orientations and locations) and graft fixation characteristics (pretension and angle of fixation). A global sensitivity analysis based on variance decomposition was used to investigate the contribution of the surgical parameters to the uncertainty in response to the ACL-R joint. Our examinations indicated that the total contact force was primarily influenced by either combined or individual action of the graft pretension and fixation angle, with a modest contribution of the graft insertion sites. The joint contact center and area were affected mainly by the angle of fixation and the tunnel placements. Graft pretension played the dominant role in the maximum contact pressure variability, an observation that has been well-documented in the literature. Interestingly, the joint contact behavior was almost insensitive to the tunnel's coronal and sagittal orientations. Our data provide an evaluation of how the surgical parameters affect the knee joint's contact behavior after ACL-R and may provide additional information to better explain the occurrence of osteoarthritis as an aftermath of such surgery.

Superior Postoperative Stability and Functional Outcomes With Anteromedial Versus Transtibial Technique of Single-Bundle Autologous Hamstring Anterior Cruciate Ligament Reconstruction: A Meta-analysis of Prospective Randomized Controlled Trials

PURPOSE

The aim of this meta-analysis was to compare the postoperative stability and functional outcomes of anteromedial (AM)- and transtibial (TT)-based single-bundle hamstring anterior cruciate ligament (ACL) reconstruction techniques.

METHODS

A meta-analysis comparing the outcomes of single-bundle hamstring ACL reconstruction using the AM and TT techniques was performed. Prospective randomized controlled trials identified from searches of PubMed, Cochrane, and Embase were included in this review. The outcome measures analyzed included postoperative Lachman test and pivot-shift test results, side-to-side difference, International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity score.

RESULTS

A total of 7 randomized controlled trials (654 patients) were included in this review. The AM technique, compared with the TT technique, resulted in superior postoperative stability based on the negative Lachman test rate (risk ratio [RR], 1.12; 95% confidence interval [CI], 1.01 to 1.24; P = .03; 95% prediction interval [PI], 0.32 to 3.46), negative pivot-shift test rate (RR, 1.16; 95% CI, 1.06 to 1.28; P = .002; 95% PI, 0.40 to 2.88), and side-to-side difference (weighted mean difference [WMD], -0.32 mm; 95% CI, -0.48 to -0.16; P < .0001; 95% PI, -0.55 to -0.09). Likewise, the AM technique contributed to superior postoperative functional outcomes based on the proportion of IKDC grade A findings (RR, 1.16; 95% CI, 1.02 to 1.32; P = .03; 95% PI, 0.40 to 2.83) and the Lysholm score (WMD, 0.82; 95% CI, 0.23 to 1.41; P = .007; 95% PI, -0.22 to 1.86). However, the AM and TT techniques had comparable subjective IKDC scores (WMD, 0.98; 95% CI, -0.91 to 2.88; P = .31; 95% PI, -3.18 to 5.14) and Tegner activity scores (WMD, 0.32; 95% CI, -0.23 to 0.86; P = .25; 95% PI, -3.84 to 4.48).

CONCLUSIONS

The AM method of single-bundle hamstring ACL reconstruction results in superior postoperative stability and functional outcomes compared with the TT method.

LEVEL OF EVIDENCE

Level I, systematic review of Level I studies.

Comparison of Clinical and Radiological Parameters with Two Different Surgical Methods for Anterior Cruciate Ligament Reconstruction

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 = 27). The patients with extracortical fixation by anatomical AMP technique were placed in Group 2 (n = 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 = 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 = 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% ± 9.86 vs. 34.11% ± 10.0%) (p = 0.001). When the localization of the tunnel enlargements (proximal-middle-distal) was examined, a significant difference was found between the groups (p = 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.

[A comparative study of arthroscopic anterior cruciate ligament reconstruction via transtibial and transportal techniques]

OBJECTIVE

To investigate the effectiveness of arthroscopic anterior cruciate ligament (ACL) reconstruction via transtibial (TT) and transportal (TP) techniques after 10 years follow-up.

METHODS

A clinical data of 103 patients who underwent arthroscopic ACL reconstruction with a single bundle of autologous hamstring tendon between March 2006 and March 2009 was retrospectively analyzed, among which 57 patients were reconstructed with TT technique (TT group) and 46 patients were reconstructed with TP technique (TP group). There was no significant difference in gender, age, cause of injury, interval between injury and operation, preoperative pivot shift test, preoperative International Knee Documentation Committee (IKDC) score, Lysholm score, and KT-2000 side-to-side difference (SSD) between the two groups ( P>0.05). At 10 years after operation, Lachman test was used to evaluate the forward joint stability and pivot shift test to evaluate the rotational stability of the knee; KT-2000 SSD was used to measure tibial anterior displacement; IKDC score and Lysholm score were used to evaluate knee function; MRI examination was performed to observe graft healing and measure coronal inclination angles of the tibia and femoral tunnels. The rate of return to sports was also calculated.

RESULTS

The incisions healed by first intention in the two groups, and no early complication occurred after operation. All patients were followed up 10-13 years, with an average of 11.5 years. During the follow-up period, there was no limitation of knee extension and flexion, no discomfort of donor site or graft failure in either group. MRI examination showed that the graft healed well. The IKDC score, Lysholm score, and KT-2000 SSD in the two groups were significantly improved after 10 years ( P<0.05), and there was no significant difference between the two groups at 10 years after operation ( P>0.05). There were significant differences in coronal inclination angles of femoral tunnel and tibial tunnel between the two groups ( P<0.05). There was no significant difference in Lachman test and pivot shift test between the two groups ( P>0.05). The rate of return to sports of patients was 61.40% (35/57) in TT group and 63.04% (29/46) in TP group, showing no significant difference between the two groups ( χ 2=0.29, P=0.87).

CONCLUSION

TT and TP techniques can both achieve good effectiveness in ACL reconstruction.

ESTUDO DA TÉCNICA INTRACAPSULAR ASSISTIDA POR ARTROSCOPIA PARA O TRATAMENTO DA RUPTURA DO LIGAMENTO CRUZADO CRANIAL EM CADÁVERES DE CÃES

Resumo O objetivo foi estudar e aprimorar a técnica intracapsular de reparação do ligamento cruzado cranial assistida por artroscopia em cadáveres de cães com a confecção dos túneis tibial e femoral e utilização de autoenxerto osso-tendão patelar-osso. Foram utilizados 10 membros pélvicos de cães > 20kg. Os túneis ósseos foram confeccionados de forma independente e na posição anatômica original dos locais de inserção do ligamento cruzado cranial. Foram realizados estudo radiográfico e tomográfico para avaliar a articulação. A coleta das porções ósseas do enxerto foi feita com osteótomo e martelo. Ocorreram fratura em três patelas e em três tuberosidades tibiais. Os enxertos apresentaram comprimento médio 7,56cm. Os túneis tibiais e os túneis femorais foram confeccionados no local de inserção do ligamento cruzado cranial em 80% e 90% das articulações, respectivamente. Os túneis tibiais apresentaram ângulo médio de 62,95º mensurado por tomografia computadorizada. Os túneis femorais foram confeccionados em posição 13hs para o joelho esquerdo (100%) e 11hs para o direito (100%). Ao final do procedimento, obteve-se gaveta negativo em 100% das articulações. Pode-se concluir que a técnica proposta é viável de ser realizada no cão, porém faz-se necessário instrumental específico devido ao pequeno tamanho da articulação canina para obter melhor acurácia.

No clinical differences between anteromedial portal and transtibial technique for femoral tunnel positioning in anterior cruciate ligament reconstruction: a prospective randomized, controlled trial

PURPOSE

The anteromedial (AMP) portal technique was introduced to position the femoral tunnel in anterior cruciate ligament (ACL) reconstruction to more closely replicate the original ACL footprint compared to the transtibial (TT) approach. Few randomized trials have evaluated differences in these techniques with respect to clinical outcomes. The purpose of this study was to determine if there are any differences in clinical outcome between the AMP and TT approaches.

METHODS

This is a single-blinded, prospective, randomized controlled trial. Participants were randomized to undergo ACL reconstruction using the AMP or TT approach. The primary outcome measure was the ACL quality of life (ACL-QOL), and secondary outcomes were the IKDC knee assessment, side-to-side difference in anterior-posterior knee laxity (KT-1000) and tunnel orientation (X-ray findings) at preoperative, 3, 6, 12, and 24 months postoperative. Statistical comparisons were performed using a series of t tests for independent groups with equal variance.

RESULTS

Ninety-six participants were consented and randomized between 2007 and 2011 with eight excluded postrandomization. Mean (SD) preoperative ACL-QOL was 33 (13) for TT and 36 (17) for AMP and improved significantly (p < 0.001) in both groups to 79 (18) and 78 (18) at 24 months postoperative, respectively. The preoperative median IKDC grade for both groups was C and improved similarly in both groups at 24 months (n.s.). There was no side-to-side difference in knee laxity based on KT-1000 measurements with a mean (SD) 1 (3) mm between affected and unaffected limbs in the TT group compared to 1 (3) mm for the AMP group. A significant difference was found in femoral tunnel orientation with the AMP group at 43° (7) and the TT group 58° (8) in the coronal plane (p < 0.001).

CONCLUSION

No differences in clinical outcome were found when comparing AMP to TT in primary ACL reconstruction using a STG graft. This prospective randomized controlled trial suggests surgeons can use either method without significantly compromising clinical outcome.

LEVEL OF EVIDENCE

I.

Inter- and Intrarater Reliability of the Femoral Tunnel Clock-Face Grading System During Anterior Cruciate Ligament Reconstruction

PURPOSE

To determine the inter- and intrarater reliability of the clock-face grading system as used by 3 fellowship-trained sports medicine surgeons.

METHODS

Arthroscopic video was taken of the femoral tunnel placement during 20 consecutive anterior cruciate ligament (ACL) reconstructions performed by 2 surgeons. All femoral tunnels were created using a medial portal technique. The video was taken using a 30° arthroscope placed in the lateral portal and showed the femoral tunnel as well as the remainder of the femoral notch, the posterior cruciate ligament, and the menisci for orientation. Three fellowship-trained sports medicine surgeons were asked to review the videos and assign an o'clock position to the femoral tunnel from the 9 to the 3 o'clock positions in "half-hour" increments. They were also asked to review the videos again 6 months later to determine intrarater reliability. Inter-rater reliability was evaluated using the intraclass correlation coefficient (ICC) 2-way mixed effect model with absolute agreement. The Spearman rank-order correlation coefficient (r) was applied to evaluate intrarater reliability.

RESULTS

The inter-rater reliability as measured by the ICC revealed poor agreement between the 3 surgeons (ICC = 0.204, 95% confidence interval = -0.015 to 0.491, F = 2.8, P = .004). The intrarater reliability at a 6-month interval was found to be moderate (r's = .43, P = .004).

CONCLUSIONS

The inter-rater reliability of the clock-face femoral tunnel grading system was found to be poor among fellowship-trained sports medicine surgeons whereas the intrarater reliability was found to be moderate. The utility of the femoral tunnel clock-face grading system may be compromised by suboptimal inter- and intrarater reliability, making it less useful as a tool of communication between surgeons.

LEVEL OF EVIDENCE

Level IV, case series with poor reference standard.

Joint stability after canine cranial cruciate ligament graft reconstruction varies among femoral fixation sites

OBJECTIVE

To quantify stability in cranial cruciate ligament (CrCL) deficient canine stifles with hamstring grafts affixed at 3 femoral locations.

STUDY DESIGN

Canine stifle motion study using a multi-cohort, repeated measures design.

SAMPLE POPULATION

27 canine cadaver stifles.

METHODS

Hamstring grafts (HG) were affixed at the gracilis-semitendinosus insertion and on the lateral femur (1) proximal trochlear ridge (TR), (2) craniodistal to fabella (F), or (3) condyle center (CC). Total, cranial, and caudal tibial translation and total, medial, and lateral angular displacement, with and without translational load, were quantified with the CrCL intact, transected, and reconstructed. Angular displacement was quantified from points on the distal femur and proximal tibia. Graft strain was calculated from tissue displacement measured at joint angles of 30°, 60°, 90°, and 120°.

RESULTS

Tibial translation was lowest in F constructs, which also achieved the least difference in tibial translation from intact stifles. Tibial translation was lower in intact stifles than in CrCL transected or reconstructed stifles. Less angular displacement of the proximal tibia was detected in the medial than in the lateral direction, and tibial displacement was lower in the cranial than the caudal direction. Angular displacement was lowest in the F treatment group. F constructs had the lowest graft strain at joint angles greater than 30°.

CONCLUSIONS

Femoral fixation of a canine hamstring graft craniodistal to the lateral fabella conferred the best joint stability and lowest graft strain in vitro. No fixation method restored joint stability of the intact CrCL.

Volumetric Damage to the Femoral Physis During Double-Bundle Posterior Cruciate Ligament Reconstruction: A Magnetic Resonance Imaging Computer Modeling Study

PURPOSE

The purpose of this study was to use computer models to evaluate the volume of femoral physeal disruption in double-bundle posterior cruciate ligament (PCL) reconstruction in patients with open physes.

METHODS

Ten skeletally immature patients (6 girls and 4 boys) were selected for this study. The magnetic resonance imaging scans of each patient were converted into a 3-dimensional model using computer-aided design/computer-aided manufacturing software. The software allowed the users to differentiate the epiphyseal, physeal, and metaphyseal tissues. This allowed for quantification of volume removed of each tissue type. Furthermore, we used the 3-dimensional models to simulate an anatomic double-bundle technique using 6-, 7-, 8-, and 9-mm-diameter tunnels. The software method reflects an inside-out drilling technique.

RESULTS

For drill holes of all diameters, the posteromedial tunnels exited the knee inferior to the physis, thus avoiding physeal damage. In contrast, all the anterolateral tunnels perforated the physis. The results for the percent of total physis removed are as follows: 6-mm tunnel, 1.79% ± 0.99%; 7-mm tunnel, 2.23% ± 1.19%; 8-mm tunnel, 3.00% ± 1.54%; and 9-mm tunnel, 3.84% ± 1.73%.

CONCLUSIONS

This computer modeling simulation of double-bundle PCL reconstruction in skeletally immature knees found that the posteromedial tunnel avoided disruption of the distal femoral physis. In contrast, the anterolateral tunnel did disrupt the physis with all drill hole sizes (6 to 9 mm), but all had a less than 4% volume of total physis removed.

CLINICAL RELEVANCE

A clear understanding of the drill hole position may reduce the volume of physeal injury during double-bundle PCL reconstruction. This study shows that physeal disruption of less than the experimental 7% threshold that has been shown to cause physeal arrest may not cause arrest, but this is still speculative.

Review of evolution of tunnel position in anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established.

Femoral and tibial tunnel positioning on graft isometry in anterior cruciate ligament reconstruction: a cadaveric study

PURPOSE

To assess distance changes between the femoral and tibial attachment points of 3 different anterior cruciate ligament (ACL) tunnel entry positions throughout the range of knee motion in cadaveric knees.

METHODS

The ACLs of 11 fresh-frozen cadaveric knees (from 6 men and 5 women) were removed using radiofrequency. Three tibial tunnel placements were made using a cannulated awl, and three 2.4-mm pilot tunnels were drilled on the lateral femoral condyle. One end of an inelastic suture was inserted from each of the 3 femoral holes and fixed on the femoral cortex using a suture button in turn, whereas the other end of the suture was passed through the cannulated awl and fixed on each of the 3 tibial placements in turn, with constant tension. Distance changes of the suture throughout the range of knee movement (0º, 90º, and 135º of knee flexion) were measured for each combination of tibial and femoral positions.

RESULTS

The distance was minimum when the knee was in full extension (p < 0.0001). Most of the distance changes occurred during initial flexion (0º-90º). The most isometric position (mean ± standard deviation [SD] distance change, 2.78 ± 0.93 mm; p < 0.0001) was noted when the suture was at the anteromedial bundle placement in the femur and anterior in the tibia. The least isometric position (mean ± SD distance change, 10.37 ± 2.08 mm; p < 0.0001) was noted when the suture was at the mid-bundle position in the femur and at the posterolateral bundle insertion in the tibia. The anatomic position resulted in a mean ± SD distance change of 7.63 ± 2.01 mm (p < 0.0001). The femoral position had a greater influence on distance change than the tibial position.

CONCLUSION

None of the ACL graft positions was isometric. Anatomic ACL positioning resulted in comparable anisometry to the native ACL. The minimum distance for all graft positions was noted in full extension, in which position the graft should be fixed during anatomic ACL reconstruction.

Anteromedial portal versus outside-in technique for creating femoral tunnels in anatomic anterior cruciate ligament reconstructions

PURPOSE

To determine whether the anteromedial (AM) portal and outside-in techniques in anterior cruciate ligament reconstruction differ (1) in the coronal femoral tunnel position, (2) in the femoral tunnel length, and (3) in the incidence of femoral tunnel-related complications, such as femoral socket blowout.

METHODS

We examined 63 knees undergone primary anterior cruciate ligament reconstructions using the AM portal technique (AM portal group) and 54 knees using the outside-in technique (outside-in group). Coronal femoral tunnel positions between the 2 groups were assessed on postoperative tunnel-view radiographs and compared. Comparisons of femoral tunnel lengths, proportions of knees with a femoral tunnel length of less than 30 mm, and incidences of femoral tunnel-related complications were performed between the 2 groups.

RESULTS

There were no significant differences in coronal femoral tunnel positions between the AM portal and outside-in groups (56.6° v 56.4°, P > .99). Differences in femoral tunnel lengths between the AM portal and outside-in groups did not reach statistical significance (37.6 mm and 39.0 mm, respectively; P = .097), but the tunnel length of the outside-in group showed smaller variation than that of the AM portal group in terms of standard deviation (2.7 v 6.0). In addition, the AM portal group had a significantly greater proportion of knees with a femoral tunnel length of less than 30 mm than the outside-in group (14% v 0%, P = .004). There were 2 tunnel-related complications (3%) (highly suspicious cortical blowouts) in the AM portal group and none in the outside-in group (P = .499).

CONCLUSIONS

This study shows that compared with the AM portal technique, the outside-in technique can achieve a similar femoral tunnel position in the coronal plane with a reduced chance of a femoral tunnel length of less than 30 mm.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Relation between anterior cruciate ligament graft obliquity and knee laxity in elite athletes at the National Football League combine

PURPOSE

The purposes of this study were to determine the incidence of vertical anterior cruciate ligament (ACL) reconstructions in elite athletes and to determine whether graft obliquity correlates with knee stability in this population.

METHODS

One hundred thirty-seven knees in 125 athletes at the 2005-2009 National Football League Combine were identified as having had previous ACL reconstructions. The graft type, fixation, and physical examination findings were recorded for each athlete. Graft obliquity was measured by previously described methods based on plain radiography and magnetic resonance imaging (MRI). Radiographic measurements included tibial tunnel and femoral tunnel locations, as well as a sum of these tunnel positions on the lateral radiograph (sum score). MRI measurements included sagittal and coronal ACL angles and the ACL-Blumensaat line angle. The relation of graft obliquity to physical examination findings was assessed.

RESULTS

Sixty-four percent of knees had vertical grafts based on radiography and 35% based on MRI criteria. The average tibial tunnel location on radiography was 33% from the anterior tibial plateau in the oblique group compared with 42% in the vertical group (P < .0001). Knees with a sum score of 66 or less, tibial tunnel 37% or less from the anterior tibial plateau, and sagittal obliquity of 60° or less were less likely to have increased translation on the Lachman examination than knees with a sum score greater than 66, tibial tunnel greater than 37% from the anterior tibial plateau, and sagittal obliquity greater than 60° (P < .05).

CONCLUSIONS

There was a wide range of ACL graft obliquity in the examined cohort of elite athletes who continued to perform at high levels. Less oblique (more vertical) grafts were associated with greater anterior tibial translation on Lachman testing. ACL graft obliquity, which is particularly sensitive to tibial tunnel placement, can influence knee stability.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Relation of tunnel enlargement and tunnel placement after single-bundle anterior cruciate ligament reconstruction

PURPOSE

To determine the relation between tunnel placement and tunnel enlargement after single-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

Seventy-two subjects (mean age, 30.1 years; 17.5 months' follow-up) who underwent single-bundle ACL reconstruction with hamstring autograft were studied. EndoButton fixation (Ethicon, Somerville, NJ) was used on the femoral side, whereas staples were used on the tibial side. A transtibial femoral tunnel position technique was used in 53 subjects, whereas positioning through the medial portal was used in the other 19 cases. Tunnel enlargement was determined by comparing the diameter of the tunnel on the radiograph obtained after 12 months and the radiograph obtained instantly after the operation. The centers of the femoral and tibial tunnels and the angles between the graft and tibial plateau were also measured on standard radiographs. Clinical outcomes including KT-1000 assessment (MEDmetric, San Diego, CA) and International Knee Documentation Committee (IKDC) score were also collected in all patients. The relations between tunnel enlargement/tunnel position and knee joint laxity and IKDC score were analyzed.

RESULTS

The mean KT-1000 side-to-side difference significantly decreased, from 6.07 ± 2.75 mm to 1.57 ± 2.14 mm, after ACL reconstruction; the IKDC subjective score increased from 52.8 to 87.5. On lateral radiographs, the tunnel enlargement rates were 41% on the femoral side and 35% on the tibial side; on plain anteroposterior radiographs, the tunnel enlargement rates were 39% on the femoral side and 32% on the tibial side. Subjects with a higher femoral tunnel had a greater enlargement rate (P < .001). Subjects with a more vertical graft also had a larger femoral enlargement (P < .05). More anterior placement of the femoral tunnel was associated with larger tibial tunnel enlargement on anteroposterior plain radiographs (P < .05). A more vertical graft was also associated with larger tibial tunnel enlargement. Subjects in whom the transtibial femoral position technique was used had more femoral tunnel enlargements (P < .01).

CONCLUSIONS

Drilling the femoral tunnel through the medial portal created a lower, more posterior, and less vertical tunnel than drilling through the tibial tunnel. Femoral and tibial tunnel enlargements were greater with more anterior, more proximal, and more vertical femoral tunnels. Whereas no clinical differences were seen in the 2 groups, drilling the femoral tunnel from the medial portal will result in smaller postoperative tunnel enlargements.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Volumetric injury of the distal femoral physis during double-bundle ACL reconstruction in children: a three-dimensional study with use of magnetic resonance imaging

BACKGROUND

Double-bundle anterior cruciate ligament (ACL) reconstruction was developed to produce a more "anatomic" reproduction of the anteromedial and posterolateral bundles of the ACL. The purpose of this study was to determine the volume of injury to the physis during double-bundle ACL reconstruction in children with open physes.

METHODS

Magnetic resonance images (MRIs) of ten knees of children were converted into three-dimensional models. Computer-aided design/computer-aided manufacturing software placed drill-holes of 6, 7, 8, and 9 mm in diameter in these models, simulating tunnels in the femur used for anatomic double-bundle ACL reconstruction. Computer-aided design/computer-aided manufacturing software was used to calculate the total physeal volume and the volume of physis that was removed by creation of the tunnels. The ratio of the physeal volume that had been removed to the total physeal volume was subsequently determined.

RESULTS

With use of 6, 7, 8, and 9-mm-diameter drill-holes in the femur, the average physeal volume removed, as a percentage of the total physeal volume, was 1.5%, 2.0%, 2.5%, and 2.9%, respectively, for the anteromedial tunnels; 2.2%, 2.9%, 3.6%, and 4.2% for the posterolateral tunnels; and 3.7%, 4.8%, 5.7%, and 6.5% for the anteromedial and posterolateral tunnels combined. The volume of physeal damage caused by the posterolateral drill-holes was greater than that produced by the anteromedial drill-holes in all subjects.

CONCLUSIONS

Drill-hole placement during ACL reconstruction produces a zone of physeal injury. Double-bundle techniques substantially increase the volume of injury to the physis, which appears to increase the risk of abnormal growth in the distal femoral physis following this surgical procedure.

Biomechanical evaluation of pediatric anterior cruciate ligament reconstruction techniques

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction rates in skeletally immature patients have risen recently because of increased injury frequency combined with growing awareness of the importance of treating them in an acute setting. Concerns over potential growth disturbances caused by traditional tunnel placement have prompted the description of several partial and complete physeal-sparing techniques.

HYPOTHESIS

Native knee kinematics will most closely be restored by the all-epiphyseal technique because it best re-creates the intra-articular ACL anatomy.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six cadaveric knees were subjected to static anteroposterior, varus, and internal rotation forces at 0°,15°, 30°, 45°, 60°, and 90° of flexion. Displacement and rotation of the tibia with respect to the femur were measured in the intact knee, after ACL disruption, and again after ACL reconstruction using all-epiphyseal, transtibial over-the-top, and iliotibial band physeal-sparing techniques.

RESULTS

Peak anteroposterior translation in the ACL intact and deficient states was 2.8 ± 1.4 mm and 7.2 ± 2.7 mm, respectively, at 30°. The all-epiphyseal reconstruction had a peak translation of 5.1 ± 2.3 mm at 30°, and the transtibial over-the-top reconstruction had a peak of 4.8 ± 1.8 mm at 30°, both significantly greater than the ACL intact state. The iliotibial band technique had a peak anteroposterior translation of 1.7 ± 1.1 mm at 45°, which was significantly less than the ACL-deficient state. Internal rotation was significantly increased in the all-epiphyseal reconstruction compared with the ACL intact state and significantly decreased at all flexion angles except 0° in the iliotibial band reconstruction. The only technique to affect varus rotation was the iliotibial band reconstruction, which significantly decreased varus rotation from the ACL-deficient state at flexion angles greater than 30°.

CONCLUSION

All physeal-sparing reconstruction techniques restored some stability to the knee. The iliotibial band reconstruction best restored anteroposterior stability and rotational control, although it appeared to overconstrain the knee to rotational forces at some flexion angles.

CLINICAL RELEVANCE

This study provides orthopaedic surgeons with objective knee kinematic data to help guide them in making more informed decisions on the optimal technique for ACL reconstruction in skeletally immature patients.

Comparison of in situ forces and knee kinematics in anteromedial and high anteromedial bundle augmentation for partially ruptured anterior cruciate ligament

BACKGROUND

High tunnel placement is common in single- and double-bundle anterior cruciate ligament (ACL) reconstructions. Similar nonanatomic tunnel placement may also occur in ACL augmentation surgery.

PURPOSE

In this study, in situ forces and knee kinematics were compared between nonanatomic high anteromedial (AM) and anatomic AM augmentation in a knee with isolated AM bundle injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Seven fresh-frozen cadaver knees were used (age, 48 ± 12.5 years). First, intact knee kinematics was tested with a robotic-universal force sensor testing system under 2 loading conditions. An 89-N anterior load was applied, and an anterior tibial translation was measured at knee flexion angles of 0°, 30°, 60°, and 90°. Then, combined rotatory loads of 7-N·m valgus and 5-N·m internal tibial rotation were applied at 15° and 30° of knee flexion angles, which mimic the pivot shift. Afterward, only the AM bundle of the ACL was cut arthroscopically, keeping the posterolateral bundle intact. The knee was again tested using the intact knee kinematics to measure the in situ force of the AM bundle. Then, arthroscopic anatomic AM bundle reconstruction was performed with an allograft, and the knee was tested to give the in situ force of the reconstructed AM bundle. Knee kinematics under the 3 conditions (intact, anatomic AM augmentation, and nonanatomic high AM augmentation) and the in situ force were compared and analyzed.

RESULT

The high AM graft had significantly lower in situ force than the intact and anatomic reconstructed AM bundle at 0° of knee flexion (P < .05) and the intact AM bundle at 30° of knee flexion under anterior tibial loading. There were no differences between anatomic graft and intact AM bundle. The high AM graft also had a significantly lower in situ force than the intact and anatomic reconstructed AM with simulated pivot-shift loading at 15° and 30° of flexion (P < .05). Under anterior tibial and rotatory loading, there was a difference in tibial displacement between anatomic and high AM reconstructions and between the high AM graft and intact ACL under rotational loading with the knee at 15° of flexion.

CLINICAL RELEVANCE

Anatomic AM augmentation can lead to biomechanical advantages at time zero when compared with the nonanatomic (high AM) augmentation. Anatomic AM augmentation better restores the knee kinematics to the intact ACL state.

The effects of femoral graft placement on in vivo knee kinematics after anterior cruciate ligament reconstruction

Achieving anatomical graft placement remains a concern in Anterior Cruciate Ligament (ACL) reconstruction. The purpose of this study was to quantify the effect of femoral graft placement on the ability of ACL reconstruction to restore normal knee kinematics under in vivo loading conditions. Two different groups of patients were studied: one in which the femoral tunnel was placed near the anterior and proximal border of the ACL (anteroproximal group, n=12) and another where the femoral tunnel was placed near the center of the ACL (anatomic group, n=10) MR imaging and biplanar fluoroscopy were used to measure in vivo kinematics in these patients during a quasi-static lunge. Patients with anteroproximal graft placement had up to 3.4mm more anterior tibial translation, 1.1mm more medial tibial translation and 3.7° more internal tibial rotation compared to the contralateral side. Patients with anatomic graft placement had motion that more closely replicated that of the intact knee, with anterior tibial translation within 0.8mm, medial tibial translation within 0.5mm, and internal tibial rotation within 1°. Grafts placed anteroproximally on the femur likely provide insufficient restraint to these motions due to a more vertical orientation. Anatomical femoral placement of the graft is more likely to reproduce normal ACL orientation, resulting in a more stable knee. Therefore, achieving anatomical graft placement on the femur is crucial to restoring normal knee function and may decrease the rates of joint degeneration after ACL reconstruction.

Comparative outcome analysis of malpositioned and properly positioned fixation groups after hamstring autograft ACL reconstruction with femoral cross-pin fixation

Anterior cruciate ligament (ACL) reconstruction using soft tissue grafts has been gaining in popularity. Cross-pin fixation is used frequently, and its principle of fixation is an expansion mechanism. However, some malpositioned cases have been reported, and these malpositions may cause poor outcomes. Our aim was to compare the stability and clinical results between malpositioned and properly positioned cases. From November 2003 to December 2007, 41 patients were enrolled in this study. We divided these patients into malpositioned and properly positioned subgroups. The malpositioned group was defined by the presence of any finding among the following: posteriorly directed cross-pin to the posterior condylar line upon axial imaging, breakage upon coronal imaging, and outside-positioned cross-pin to the distal femoral posterior cortex upon sagittal imaging. We compared clinical and stability results between the two groups. Twenty-three patients were included in the properly positioned group, and 18 in the malpositioned group. The intra-class correlation coefficient for the intra- and inter-rater agreement ranged from 0.88 to 0.93 (0.88, 0.91, 0.91, and 0.93). No significant differences were found between the two groups in the stability assessment using a KT-2000 arthrometer and pivot-shift test (P=0.93 and 0.78, respectively). No significant differences were found between the two groups in the clinical knee scales (Ps=0.08-0.93). This study showed that some malpositions can occur with cross-pin femoral fixation. However, we obtained comparable good outcomes regardless of the fixation strategies if the initial fixation was correct.

Double-bundle versus single-bundle ACL reconstruction using the horizontal femoral position: a prospective, randomized study

The aim of this study was to evaluate whether anterior cruciate ligament (ACL) reconstruction using the double bundle technique (DB) improves stability in the knee compared with the single bundle technique (SB) with the femoral tunnel in a more horizontal position (2 or 10 o'clock). We conducted a randomized, prospective study. Forty patients were randomized to the DB group (20 patients) and the SB group (20 patients). Four-stranded semitendinosus and gracilis autologous grafts were used in the SB group and in the DB group the conventional four tunnel technique was carried out using the same tendons. The IKDC complete form was used for the preoperative evaluation, and in the follow-up the IKDC subjective knee evaluation form, IKDC current health assessment form and IKDC knee examination form were used. Anteroposterior (AP) laxity was evaluated by standardised and forced radiology in all patients. No significant preoperative between-group differences were found. During the follow-up, no differences were found between groups, except for significant between-group differences (P < 0.05) between the preoperative and postoperative evaluations. The IKDC index also showed significant differences in the 2-year follow-up. Median scores increased from 48 (range 41-54) to 81 (range 75-87) (P = 0.01) in the SB group and from 52 (range 46-58) to 80 (range 72-88) (P = 0.02) in the DB group. There were no significant differences between the groups in terms of functional scores. In conclusion, the 2 and 10 o'clock placements showed no significant differences between SB and DB techniques in the pivot-shift test, manual and radiological anterior posterior laxity and IKDC scores. However, significant between-group differences were found between the preoperative and postoperative evaluations.

Femoral tunnel placement during anterior cruciate ligament reconstruction: an in vivo imaging analysis comparing transtibial and 2-incision tibial tunnel-independent techniques

BACKGROUND

Recent studies have questioned the ability of the transtibial technique to place the anterior cruciate ligament graft within the footprint of the anterior cruciate ligament on the femur. There are limited data directly comparing the abilities of transtibial and tibial tunnel-independent techniques to place the graft anatomically at the femoral attachment site of the anterior cruciate ligament in patients.

HYPOTHESIS

Because placement with the tibial tunnel-independent technique is unconstrained by the tibial tunnel, it would allow for more anatomic tunnel placement compared with the transtibial technique.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

High-resolution, multiplanar magnetic resonance imaging and advanced 3-dimensional modeling techniques were used to measure in vivo femoral tunnel placement in 8 patients with the transtibial technique and 8 patients with a tibial tunnel-independent technique. Femoral tunnel placement in 3 dimensions was measured relative to the center of the native anterior cruciate ligament attachment on the intact contralateral knee.

RESULTS

The tibial tunnel-independent technique placed the graft closer to the center of the native anterior cruciate ligament attachment compared with the transtibial technique. The transtibial technique placed the tunnel center an average of 9 mm from the center of the anterior cruciate ligament attachment, compared with 3 mm for the tibial tunnel-independent technique. The transtibial technique resulted in a more anterior and superior placement of the tunnel compared with the tibial tunnel- independent technique.

CONCLUSION

The tibial tunnel-independent technique allowed for more anatomic femoral tunnel placement compared with the transtibial technique.

Transtibial versus anteromedial portal of the femoral tunnel in ACL reconstruction: a cadaveric study

The aim of this cadaveric study was to compare the transtibial versus the anteromedial portal with respect to the anatomic femoral positioning of the ACL attachment. Ten fresh frozen cadaveric knees were included in our study. A standard arthroscopy was performed and the normal ACL was partially cut through with arthroscopic scissors leaving a small footprint of 2 mm at the anatomical insertion area on the lateral femoral condyle. The femoral tunnel was drilled through the tibial tunnel and subsequently through the anteromedial portal. Using a probe with standard magnification, we measured the distances of the two femoral tunnels from the margin of ACL footprint arthroscopically. The femurs were then dissected and we measured the distances of the two tunnels from the posterior part of the lateral femoral condyle. The median arthroscopically measured distance of the centers of transtibial femoral tunnel and of the femoral tunnel through the anteromedial portal from the margin of the femoral ACL footprint were 6.20 mm and 2.80 mm respectively. The difference was statistically significant. After femoral dissection the median distance of the centers of the transtibial femoral tunnel and the femoral tunnel performed through the anteromedial portal from the border of the articular surface at the lateral femoral condyle was 6.10 mm and 5.25 mm respectively (p<0.001). Both measurements showed that ACL reconstruction technique through the anteromedial portal is more accurate compared to the transtibial technique.

A reproducible landmark for the tibial tunnel origin in anterior cruciate ligament reconstruction: avoiding a vertical graft in the coronal plane

Improper tunnel placement during anterior cruciate ligament reconstruction may result in residual instability. Proper femoral tunnel orientation relies on tibial tunnel placement with a transtibial technique. Our recommended technique is to use the junction of the anterior border of the superficial medial collateral ligament and the superior border of the gracilis tendon as a reproducible anatomic landmark for the tibial tunnel. In a cadaveric model the mean angle for the tibial tunnel was 65.7 degrees +/- 5.5 degrees in the coronal plane and 75 degrees +/- 7.2 degrees in the sagittal plane. By use of the clock-face method, the mean angle for the femoral tunnel was 44.9 degrees +/- 13 degrees , or approximately the 10:30 position (for a right knee) or 1:30 position (for a left knee).

Double-bundle anterior cruciate ligament reconstruction: a cadaveric study on the posterolateral tunnel position and safety of the lateral structures

PURPOSE

The aim of this study was to identify the anatomic relation between the posterolateral drill hole and the lateral structures of the knee. The length of the posterolateral tunnel and the feasibility of the EndoButton CL (Smith & Nephew, Andover, MA) as posterolateral graft fixation device was also evaluated.

METHODS

An anatomic descriptive study was performed on 24 cadaveric knees. The double-bundle anterior cruciate ligament (ACL) was reconstructed using standard arthroscopic techniques and the EndoButton CL fixation system. The study protocol was as follows: first, an arthroscopy with posterolateral pin placement and drilling of the posterolateral tunnel was performed. Subsequently, the lateral structures were dissected and the distance between the pin and the different anatomic structures was measured. From outside in, the length of the posterolateral tunnel was also measured.

RESULTS

This study shows that there is no increased risk of injuring the lateral collateral ligament during posterolateral tunnel placement in double-bundle ACL reconstruction, when performed through a low anteromedial portal in high flexion. Furthermore, a safe margin was noted between the posterolateral tunnel and the adjacent lateral gastrocnemius and popliteus tendons. The length of the posterolateral tunnel was between 32 and 44 mm (mean, 36.92 mm).

CONCLUSIONS

We conclude that the posterolateral tunnel can be created safely in double-bundle ACL reconstruction without additional risk to the surrounding structures. A 15-mm EndoButton CL fixation device is routinely advised as posterolateral graft fixation in order to avoid the risk of over-advancing the device or overdrilling.

CLINICAL RELEVANCE

This study has shown that there is no risk of iatrogenic lesion to the lateral collateral ligament, lateral gastrocnemius tendon, or popliteus tendon with a posterolateral tunnel drilled through a low anteromedial portal in high flexion.