The effect of graft placement on the clinical outcome of the anterior cruciate ligament reconstruction: a prospective study

The Influence of Tunnel Parameters and Graft Inclination Angle on Clinical and Radiological Outcome at Long-term Follow-up after Arthroscopic Anterior Cruciate Ligament Reconstruction

Objective  To study the influence of various tunnel parameters and graft inclination angle (GIA) on the clinical and radiological outcome after anterior cruciate ligament reconstruction (ACLR) at long-term follow-up. Methods  In this retrospective study, 80 patients with isolated anterior cruciate ligament (ACL) injury treated by single bundle ACLR using bone patellar tendon bone (BPTB) and hamstring (HT) autografts were evaluated clinically and radiologically at their long-term follow-up. The study population were divided into two groups based on ideal and nonideal tunnel parameters as well as ideal and nonideal GIA. The various tunnel parameters and GIA were interpreted with clinical and radiological outcome at long-term follow-up. Results  Eighty patients, 36 (45%) using BPTB and 44 (55%) using HT autografts, were available to complete the study. Patients with ideal coronal tibial tunnel angle (CTTA) and coronal femoral tunnel angle (CFTA) show superior clinical outcome (pivot shift test) than nonideal CTTA and CFTA, which was found to be statistically significant ( p -value < 0.038 and 0.024, respectively). Similarly, patients with ideal coronal tibial tunnel position (CTTP) show superior clinical outcome (International Knee Documentation Committee - IKDC objective) over nonideal CTTP ( p -value < 0.017). All other tunnel parameters and GIA were not found to have influence on clinical outcome. None of the tunnel parameters have influenced osteoarthritis (OA) change. There was no progression of OA change in the study population at long-term follow-up after ACLR. Conclusion  Ideal coronal tunnel parameters produced a better clinical outcome at long-term follow-up after ACLR. There was no progression of OA change at long-term follow-up after isolated ACLR.

Failure rate analysis and clinical outcomes of two different femoral tunnel positions using anteromedial portal technique in anterior cruciate ligament reconstruction

AIM

To analyze two different femoral tunnel positions and to evaluate their correlation with clinical, functional outcomes and surgical revision rate in patients who underwent primary arthroscopic anterior cruciate ligament (ACL) reconstruction with anteromedial (AM) portal technique.

METHODS

From January 2015 to October 2018, we recruited 244 patients that underwent primary single-bundle ACL reconstruction, using four strand-semitendinosus graft and AM portal technique for femoral tunnel placement. Patients were divided into two groups based on the different femoral tunnel positions: 117 patients of group A had ACL footprint center femoral tunnel position compared with 127 patients of group B, with femoral tunnel placement close to the AM bundle footprint. Preoperatively and at last follow up, all patients were assessed subjectively by Lysholm, Tegner, and International Knee Documentation Committee (IKDC) scores, while Lachman, Pivot-shift, and KT-1000 tests were performed to evaluate knee joint stability.

RESULTS

Group B patients showed significantly better results in Lysholm, objective, and subjective IKDC scores compared with patients of group A (P < 0.001). A significantly higher surgical failure rate was found in group A than in group B (10.26% vs. 2.3%; P < 0.001). A higher anterior knee laxity was recorded in patients of group A than in patients of group B (1.9 ± 1.1 vs. 1.3 ± 1 mm; P < 0.001); a reduction in mean anterior tibial translation from preoperative to final follow up was found in group B compared with group A (3.5 ± 1.2 vs. 2.7 ± 1.1 mm; P < 0.001). No significant differences in the Tegner scale were found between the two groups.

CONCLUSION

ACL reconstruction performed using the AM portal technique showed better and more satisfactory clinical and functional outcomes associated with a lower failure rate when the femoral tunnel had been placed more eccentrically in the footprint, in the AM bundle center position.

Posteriorly positioned femoral grafts decrease long-term failure in anterior cruciate ligament reconstruction, femoral and tibial graft positions did not affect long-term reported outcome

PURPOSE

To investigate the effect that femoral and tibial tunnel positions have on long-term reported and clinical outcome and to identify a safe zone based on favourable outcome.

METHODS

Seventy-eight patients from a previous randomised controlled trial were included and were followed with a mean follow-up of 11.4 years. All patients had primary trans-tibial anterior cruciate ligament reconstruction performed. The femoral and tibial tunnel positions were visualised and translated in percentages with three-dimensional computed tomography post-operatively. There were 3 separate outcome variables: patient-reported outcome measured with the IKDC Subjective Knee Form, overall failure, and radiographic osteoarthritis. The correlation between tunnel aperture positions and outcome was determined with multivariate regression. The area with best outcome was defined as the safe zone and was determined with Youden's index in conjunction with receiver operating characteristics.

RESULTS

No significant relationship was found between tunnel aperture positions and IKDC Subjective Knee Form at 10-year follow-up. The posterior-to-anterior femoral tunnel aperture position parallel to Blumensaat line showed a significant relationship (p = 0.03) to overall failure at 10-year follow-up. The mean posterior-to-anterior tunnel position of the group that did not fail was 37.7% compared to 44.1% in the overall failure group. Femoral tunnel apertures placed further anteriorly had more overall failures at long-term. The cut-off point lies at 35.0% from posterior-to-anterior parallel to Blumensaat. Of the 16 overall failures, 15 (93.8%) were placed further anteriorly than the cut-off point. No significant relationship was found between tunnel aperture positions and radiographic osteoarthritis.

CONCLUSION

Femoral and tibial tunnel positions were not associated with long-term patient-reported outcome and radiographic osteoarthritis. Long-term overall failure was more frequently seen in patients with a more anteriorly placed femoral tunnel. This study identified a safe zone located at the most posterior 35% of the femoral condyle parallel to Blumensaat. This knowledge offers guidance to surgeons to operate more precisely and accurately and reconstruct a long-lasting graft.

LEVEL OF EVIDENCE

Level III.

Remnant preservation does not affect accuracy of tibial tunnel positioning in single-bundle ACL reconstruction

PURPOSE

Remnant preservation, in anterior cruciate ligament (ACL) reconstruction, has potential biological advantages. However, graft positioning remains vital to functional outcome and the prevention of failure. The aim of this study was to investigate the accuracy and precision of tibial tunnel positioning in remnant preservation single-bundle hamstring reconstruction.

METHODS

Fifty consecutive adult patients, with isolated ACL rupture, were recruited to a prospective study. Remnant preservation was performed in all cases where > 25% of the native ACL was present. Three-dimensional computer tomography was preformed 3-6 months post-operatively to assess tibial tunnel position (using a grid-based measurement). Accuracy and precision of this technique were assessed against published anatomical data in direct comparison with the group where remnant preservation could not be performed.

RESULTS

Two patients withdrew following surgery. In the remaining groups (31 remnant preservation; 17 non-remnant preservation), no difference was demonstrated in tunnel position (40.4 ± 6.7% (anterior-to-posterior) and 47.4 ± 1.5% (medial-to-lateral) vs. 38.8 ± 4.9% and 46.7 ± 1.5%, respectively; n.s.), accuracy (6.1% vs. 4.8%; n.s.) or precision (3.9% vs. 2.8%; n.s.).

CONCLUSIONS

Remnant preservation can be safely performed without compromising tunnel position. Therefore, the potential benefits of this technique can be utilised, in clinical practice, without sacrificing the ability to optimize tibial tunnel positioning.

LEVEL OF EVIDENCE

III.

Techniques for Femoral Socket Creation in ACL Reconstruction

Anterior cruciate ligament (ACL) injury is common and affects a wide variety of individuals. An ACL reconstruction is the treatment of choice for patients with subjective and objective symptoms of instability and is of particular importance to cutting or pivoting athletes. With many variables involved in ACL reconstruction, femoral tunnel placement has been found to affect clinical outcomes with nonanatomic placement being identified as the most common technical error. Traditionally the femoral tunnel was created through the tibial tunnel or transtibial with the use of a guide and a rigid reaming system. Because of proximal, nonanatomic tunnel placement using the transtibial technique, the use of the anteromedial portal and outside-in drilling techniques has allowed placement of the tunnel over the femoral footprint. In this paper, we discuss the difference between the 3 techniques and the advantages and disadvantages of each. The authors then explore the clinical differences and outcomes in techniques by reviewing the relevant literature.

A comparison of femoral tunnel placement in ACL reconstruction using a 70° arthroscope through the anterolateral portal versus a 30° arthroscope through the anteromedial portal: a pilot 3D-CT study

Background

Graft malposition is a risk factor for failure of anterior cruciate ligament reconstruction. A 70° arthroscope improves visualisation of the medial wall of the lateral femoral condyle without switching portals. We investigated whether the use of this arthroscope affected the accuracy and precision of femoral tunnel placement.

Methods

Fifty consecutive adult patients were recruited. Following one withdrawal and two exclusions, 47 patients (30 in group 1 (70° arthroscope), 17 in group 2 (30° arthroscope)) underwent three-dimensional computed tomography imaging using a grid-based system to measure tunnel position.

Results

No difference was found in the accuracy or precision of tunnels (mean position: group 1 = 33.3 ± 6.0% deep–shallow, 27.2 ± 5.2% high–low; group 2 = 31.7 ± 6.9% deep–shallow, 29.0 ± 6.2% high–low; not significant). A post-hoc power analysis suggests a study of 106 patients would be required.

Conclusions

This pilot study suggests that tunnel position is not affected by the arthroscope used. An appropriately powered study could investigate this finding alongside other potential benefits of using a 70° arthroscope for this procedure.

Trial registration

ClinicalTrials.gov, NCT02816606. Registered on 28 June 2016.

Modified transtibial versus anteromedial portal techniques for anterior cruciate ligament reconstruction, a comparative study

PURPOSE

This study compared the accessory anteromedial portal (AAMP) and the modified transtibial technique (MTTT)" for single-bundle anterior cruciate ligament (ACL) reconstruction.

PATIENTS AND METHODS

Sixty active adult patients with ACL tear were randomly assigned into two equal groups who were treated surgically. One group was operated on using AAMP and the other group through MTTT. Both the groups had the same postoperative course and were followed for 1 year after surgery. The follow-up included Lysholm and International Knee Documentation Committee (IKDC) subjective knee evaluation forms, IKDC objective knee examination form, and radiological evaluation. Results were evaluated and compared with each other.

RESULTS

There was no significant difference in subjective effects or clinical examination between the two groups. Regarding radiological angles, the AAMP had more oblique graft orientation in the coronal plane than the MTTT, but both were found to be more slanted than native ACL. Also, the MTTT had succeeded to place the graft and tunnel more obliquity than the traditional non-anatomic TTT and better than the anatomic ranges despite having the graft inclination of the AAMP higher than the MTTT. The complaints from the patients and subjective scoring were found to be positively related to graft stability. Patients with healthier preoperative subjective state had a smoother postoperative period and better outcome.

CONCLUSION

This study offers simple modifications to the transtibial technique to allow near anatomic ACL reconstruction with similar results comparable to the AAMP and with fewer complications.

Quantitative radiographic assessment of the anatomic attachment sites of the anterior and posterior complexes of the proximal tibiofibular joint

PURPOSE

Quantitative guidelines for radiographic identification of the anterior and posterior ligaments of the proximal tibiofibular joint have not been well defined. The purpose of this study was to provide reproducible, quantitative descriptions of radiographic landmarks identifying the anterior and posterior ligament complexes of the proximal tibiofibular joint. It was hypothesized that consistent quantitative data regarding the radiographic location of the anterior and posterior proximal tibiofibular joint ligament complexes could be identified.

METHODS

The footprint centers of the individual ligament bundles of the anterior and posterior complexes of the proximal tibiofibular joint were labeled with radio-opaque markers in ten non-paired, fresh-frozen cadaveric knee specimens. Anteroposterior (AP) and lateral radiographs of the proximal tibiofibular joint were obtained, and distances between the markers and pertinent radiographic landmarks were recorded.

RESULTS

On AP radiographs, the tibial span of the anterior complex was 12.8 ± 3.9 mm and started at a median of 11.4 mm distal to the tibial plateau; the fibular span was 11.6 ± 6.8 mm and started at a median of 5.1 mm from the apex of the fibular styloid. The tibial span of the posterior complex was 11.7 ± 8.4 mm and began at a median of 12.1 mm distal to the tibial plateau; the fibular span was 11.8 ± 7.9 mm and began at a median of 3.1 mm distal to the apex of the fibular styloid. Values were similar for lateral radiographs.

CONCLUSION

The attachment locations of the proximal tibiofibular anterior and posterior complexes could be quantitatively correlated to reliable osseous landmarks and radiographic lines. This information will allow for consistent radiographic assessments of proper tunnel placement intraoperatively and postoperatively during anatomic reconstructions of the proximal tibiofibular joint.

Post-operative 3D CT feedback improves accuracy and precision in the learning curve of anatomic ACL femoral tunnel placement

PURPOSE

To evaluate the feedback from post-operative three-dimensional computed tomography (3D-CT) on femoral tunnel placement in the learning process, to obtain an anatomic anterior cruciate ligament (ACL) reconstruction.

METHODS

A series of 60 consecutive patients undergoing primary ACL reconstruction using autologous hamstrings single-bundle outside-in technique were prospectively included in the study. ACL reconstructions were performed by the same trainee-surgeon during his learning phase of anatomic ACL femoral tunnel placement. A CT scan with dedicated tunnel study was performed in all patients within 48 h after surgery. The data obtained from the CT scan were processed into a three-dimensional surface model, and a true medial view of the lateral femoral condyle was used for the femoral tunnel placement analysis. Two independent examiners analysed the tunnel placements. The centre of femoral tunnel was measured using a quadrant method as described by Bernard and Hertel. The coordinates measured were compared with anatomic coordinates values described in the literature [deep-to-shallow distance (X-axis) 28.5%; high-to-low distance (Y-axis) 35.2%]. Tunnel placement was evaluated in terms of accuracy and precision. After each ACL reconstruction, results were shown to the surgeon to receive an instant feedback in order to achieve accurate correction and improve tunnel placement for the next surgery. Complications and arthroscopic time were also recorded.

RESULTS

Results were divided into three consecutive series (1, 2, 3) of 20 patients each. A trend to placing femoral tunnel slightly shallow in deep-to-shallow distance and slightly high in high-to-low distance was observed in the first and the second series. A progressive improvement in tunnel position was recorded from the first to second series and from the second to the third series. Both accuracy (+52.4%) and precision (+55.7%) increased from the first to the third series (p < 0.001). Arthroscopic time decreased from a mean of 105 min in the first series to 57 min in the third series (p < 0.001). After 50 ACL reconstructions, a satisfactory anatomic femoral tunnel was reached.

CONCLUSION

Feedback from post-operative 3D-CT is effective in the learning process to improve accuracy and precision of femoral tunnel placement in order to obtain anatomic ACL reconstruction and helps to reduce also arthroscopic time and learning curve. For clinical relevance, trainee-surgeons should use feedback from post-operative 3DCT to learn anatomic ACL femoral tunnel placement and apply it appropriately.

LEVEL OF EVIDENCE

Consecutive case series, Level IV.

Tunnel positioning assessment after anterior cruciate ligament reconstruction at 12months: Comparison between 3D CT and 3D MRI. A pilot study

BACKGROUND

Tunnel positioning assessment is a major issue after anterior cruciate ligament (ACL) reconstruction surgery. Historically, it used plain X-ray and, more recently, CT with 3D reconstruction. MRI is a reliable method of assessing ACL graft integrity and postoperative complications. To our knowledge, there have been no studies of efficacy in tunnel positioning assessment. The aim of this study was to assess the efficacy of 3D MRI in assessing femoral and tibial tunnel positioning after ACL reconstruction. The hypothesis was that 3D MRI sequences with reconstruction are as accurate as 3D CT for tunnel positioning assessment in ACL reconstruction.

METHODS

Twenty-two patients who underwent an arthroscopic ACL reconstruction using hamstring graft were included in a prospective study. All patients were examined on 3D CT and 3D MRI at 12months post-surgery. Tunnel positioning was assessed on both imaging systems by a musculoskeletal radiologist and an orthopedic surgeon specialized in knee arthroscopy, both blind to all clinical data.

RESULTS

No statistically significant difference was found between 3D CT and 3D MRI on coronal and sagittal reconstructions. For coronal assessment of tibial tunnel orifice, sagittal assessment of tibial tunnel orifice and sagittal assessment of femoral tunnel orifice, P-values ranged from 0.37 to 0.99, 0.051 to 0.64 and 0.19 to 0.59, respectively. For tibial and femoral tunnel angulation, P-values were respectively 0.52 and 0.29.

CONCLUSION

3D MRI is a reliable method to assess femoral and tibia tunnel positioning in ACL reconstruction, compared to 3D CT as gold standard. Indeed, in our opinion 3D MRI could in the future replace CT for ACL reconstruction assessment, concerning not only the meniscus and ligaments but also tunnel position.

LEVEL OF EVIDENCE

Level 3; comparative prospective study.

Factors That Predict Failure in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

BACKGROUND

Anatomic graft placement in anterior cruciate ligament (ACL) reconstruction has become the preferred technique for many surgeons. The predictive factors for graft failure in anatomic single-bundle ACL reconstruction are relatively unknown.

PURPOSE

To determine the risk factors for graft failure and the relative importance of those factors in anatomic single-bundle ACL reconstruction.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

All primary anatomic ACL reconstructions undertaken at a single institution over a 2-year period were evaluated for subjective and objective measures of graft failure. Risk factors evaluated included time since ACL rupture, age, sex, body mass index, intact or deficient medial and lateral meniscus, meniscal repair, hamstring graft size, and femoral and tibial tunnel position as assessed by 3D computed tomography (CT) scan. The significant factors predicting failure and the relative importance of those factors were determined.

RESULTS

At a median follow-up of 26 months, 123 patients were available for analysis. Ninety-seven patients underwent postoperative 3D CT for tunnel positions, including all 20 cases with graft failure. The significant predictors of graft failure were medial meniscal deficiency (hazard ratio [HR] 15.1; 95% CI, 4.7-48.5; P < .001), lateral meniscal deficiency (HR 9.9; 95% CI, 3-33; P < .001), shallow nonanatomic femoral tunnel positioning (HR 4.3; 95% CI, 1.6-11.6; P = .004), and younger patient age (HR 0.9; 95% CI, 0.9-1; P = .008).

CONCLUSION

Meniscal deficiency is the most significant factor to predict graft failure in single-bundle anatomic ACL reconstruction. Shallow nonanatomic femoral tunnel positioning and younger patient age are additional risk factors for failure, but their relative importance is less.

Anatomic ACL reconstruction: the normal central tibial footprint position and a standardised technique for measuring tibial tunnel location on 3D CT

PURPOSE

The aim of this study was to define the normal ACL central tibial footprint position and describe a standardised technique of measuring tibial tunnel location on 3D CT for anatomic single-bundle ACL reconstruction.

METHODS

The central position of the ACL tibial attachment site was determined on 76 MRI scans of young individuals. The central footprint position was referenced in the anterior-posterior (A-P) and medial-lateral (M-L) planes on a grid system over the widest portion of the proximal tibia. 3D CT images of 26 young individuals had a simulated tibial tunnel centred within the bony landmarks of the ACL footprint, and the same grid system was applied over the widest portion of the proximal tibia. The MRI central footprint position was compared to the 3D CT central footprint position to validate the technique and results.

RESULTS

The median age of the 76 MRI subjects was 24 years, with 32 females and 44 males. The ACL central footprint position was at 39 (±3 %) and 48 (±2 %), in the A-P and M-L planes, respectively. There was no significant difference in this position between sexes. The median age of the 26 CT subjects was 25.5 years, with 10 females and 16 males. The central position of the bony ACL footprint was at 38 (±2 %) and 48 (±2 %), in the A-P and M-L planes, respectively. The MRI and CT central footprint positions were not significantly different in relation to the medial position, but were different in relation to the anterior position (A-P 39 % vs. 38 %, p = 0.01). The absolute difference between the central MRI and CT reference positions was 0.45 mm.

CONCLUSIONS

The ACL's normal central tibial footprint reference position has been defined, and the technique of measuring tibial tunnel location with a standardised grid system is described. This study will assist surgeons in evaluating tibial tunnel position in anatomic single-bundle ACL reconstruction.

LEVEL OF EVIDENCE

III.

Comparison of transtibial and retrograde outside-in techniques of anterior cruciate ligament reconstruction in terms of graft nature and clinical outcomes: a case control study using 3T MRI

INTRODUCTION

This study was performed to compare ACL graft maturation and morphologies using MRI between trans-tibial (TT) and retrograde outside-in (OI) techniques, and to compare clinical outcomes between the two groups.

MATERIALS AND METHODS

Patients underwent single-tunnel ACL reconstruction using quadrupled hamstring autografts, with the TT technique used on 42 patients (TT group) and the retrograde OI technique used on 39 patients (OI group). All patients were examined with 3 T MRI at 6 months (between 5 and 7 months) after surgery. The signal intensity of the reconstructed graft was analyzed and compared between the two groups, using the signal/noise quotient (SNQ), the orientation of the ACL graft and the tibial tunnel location of the graft. The SNQ value is indicative of graft maturation, and the orientation of the graft and the tibial tunnel location of the graft represent graft morphology. Clinical evaluation was performed before the surgery and 2 years or more after the surgery.

RESULTS

The mean SNQ value of the TT group was significantly (P = 0.030) lower than that of the OI group. The mean sagittal ACL angle (P < 0.001) and the mean coronal ACL angle (P < 0.001) were more vertical in the TT group. The tibial tunnel aperture was located at a significantly (P < 0.001) more posterior position in the TT group. There was no statistically significant difference in the clinical results between the two groups.

CONCLUSIONS

The OI technique showed a more anteriorly positioned tibial tunnel and a more oblique graft orientation in both sagittal and coronal planes. However, in comparison with the TT group, a significantly higher SNQ value was noticed in the follow-up MRI of the OI group at 6 months, although clinical results of the two groups were not significantly different during at least the 2-year follow-up.

The influence of graft placement on clinical outcome in anterior cruciate ligament reconstruction

PURPOSE

the aim of the present study was to investigate the influence of graft tunnel position on both clinical outcome and instrumental knee stability in patients submitted to arthroscopic ACL reconstruction using a bone-patellar tendon-bone (BPTB) graft.

METHODS

thirty patients (24 men and 6 women) who underwent ACL reconstruction performed using an autologous bone-patellar tendon-bone graft were studied at a mean follow-up of 18 months. Clinical outcome was assessed on the basis of the Lysholm score, Tegner activity level, International Knee Documentation Committee (IKDC) subjective form and the Short Form-36. Clinical outcomes were correlated with both femoral and tibial tunnel placement measured on standard anteroposterior and lateral knee radiographs, in accordance with established guidelines.

RESULTS

tibial tunnel position on the lateral view correlated significantly with both the IKDC subjective form (r = -0.72; p<0.05) and the Lysholm score (r=-0.73; p<0.05). Tibial tunnel position on the lateral view also correlated with stability measured using a KT-1000 arthrometer at 30N of force (r=0.57; p<0.05). No correlation was found between α angle and anteroposterior (AP) laxity measured by KT-1000 arthrometer. No significant correlation was found between femoral tunnel position (on either view) and Lysholm score, IKDC score and Tegner activity level. Similarly, no correlation was found between AP laxity measured by KT-1000 arthrometer and femoral tunnel position.

CONCLUSIONS

these results suggest that the more anterior the placement of the tibial tunnel, the better the clinical outcome will be. On the basis of literature data and our findings, we discuss the hypothesis that there exists a "correct area" for tunnel placement, making it possible to obtain the best results.

LEVEL OF EVIDENCE

Level IV, case series.

CT assessment of femoral tunnel placement after partial ACL reconstruction

INTRODUCTION

When one of the anterior cruciate ligament (ACL) bundles is torn, it seems appropriate to preserve the remaining bundle to improve the vascularization and proprioception of the graft, and to reproduce the attachment sites of the torn bundle. After ACL reconstruction, the functional result is worse when the tunnels are positioned further away from the native ACL's isometric attachment points. The goal of this study was to use CT 3D reconstructions to analyse the position of the femoral tunnel following partial ACL reconstruction and to compare it to complete ACL reconstruction cases. We hypothesized that the femoral tunnel positioning was optimal during partial ACL reconstruction.

METHODS

In this prospective single-centre study, 16 patients who underwent isolated anteromedial bundle reconstruction were evaluated during the immediate postoperative period using 3D reconstruction of CT images. During this same period, 180 patients who underwent complete ACL reconstruction in the same surgery unit served as a control group.

RESULTS

In the partial ACL reconstruction group, 6 tunnels (37.5%) were in the optimal position and 10 tunnels (62.5%) were not. In the complete ACL reconstruction group, 124 femoral (68.9%) were in the optimal position and 56 (31.1%) were not (P<0.05).

DISCUSSION

Femoral tunnel positioning is not always optimal in patients who undergo partial ACL reconstruction. Three-dimensional CT reconstruction is a good tool to help surgeons detect and learn from their errors.

LEVEL OF EVIDENCE

III (case-control study).

Bioabsorbable Versus Titanium Screws in Anterior Cruciate Ligament Reconstruction Using Hamstring Autograft: A Prospective, Blinded, Randomized Controlled Trial With 5-Year Follow-up

BACKGROUND

Longer-term results of bioabsorbable screws for anterior cruciate ligament reconstruction (ACLR) have been reported, but results are specific to the exact screw material and design. Titanium and poly-L-lactic acid with hydroxyapatite (PLLA-HA) screw outcomes have been compared only to 2 years.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the clinical and radiologic outcomes of the PLLA-HA screw versus titanium screw for hamstring tendon ACLR over a 5-year follow-up period. The hypothesis was that there are no differences in clinical scores or tunnel widening between the PLLA-HA and the titanium screws and that the PLLA-HA screw as seen on magnetic resonance imaging (MRI) should show high-grade resorption and ossification response over 5 years.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 40 patients undergoing ACLR were randomized to receive either a PLLA-HA screw (PLLA-HA group) or a titanium screw (titanium group) for ACL fixation. Blinded evaluation was performed at 2 and 5 years with the International Knee Documentation Committee and Lysholm knee score, KT-1000 arthrometer, single-legged hop test, and MRI to evaluate tunnel and screw volumes, periscrew ossification, graft integration, and cyst formation.

RESULTS

There was no difference in any clinical outcome measure at 2- or 5-year follow-up between the 2 groups. At 2 years, the femoral tunnel in the PLLA-HA group was smaller than that in the titanium group (P = .02); at 5 years, there was no difference. At 2 years, the femoral PLLA-HA screw was a mean 76% of its original volume, and by 5 years, it was 36%. At 2 years, the tibial PLLA-HA screw mean volume was 68% of its original volume, and by 5 years, it was 46%. At 5 years in the PLLA-HA group, 88% of femoral tunnels and 56% of tibial tunnels demonstrated a significant ossification response. There was no increase in cyst formation in the PLLA-HA group and no screw breakages.

CONCLUSION

There were equivalent clinical results between the PLLA-HA and titanium groups at 2- and 5-year follow-ups. The PLLA-HA screw was not associated with increased tunnel widening or cyst formation when compared with the titanium screw. The PLLA-HA screw demonstrated progressive screw resorption and gradual but incomplete ossification over 5 years.

A randomized prospective controlled study with 5-year follow-up of cross-pin femoral fixation versus metal interference screw fixation in anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to determine and compare mid- to long-term results of cross-pin versus metal interference screw fixation of ACL graft.

METHODS

In a prospective trial, 62 patients were randomized into two groups based on method of fixation. Transtibial drilling technique was used in the cross-pin and outside-in femoral drilling in the interference screw fixation group. Clinical and radiographical outcomes were assessed 2 and 5 years postoperatively.

RESULTS

The study showed no clinically significant difference with respect to method of graft fixation. Mean anteroposterior side-to-side instrumented laxity difference was 2.4 mm in the cross-pin group and 2.5 mm in the screw group (n.s.). Median Tegner and mean Lysholm scores at 5 years were 6 (range 3-9) and 92.2 (range 69-100) in the screw group and 7 (3-10) and 93.3 (82-100), respectively, in the cross-pin group. Radiographical osteoarthritis increased in both groups from 2 to 5 years after reconstruction (p < 0.05), especially in the medial and patellofemoral joint spaces. Widening of the drill tunnels continued from 2 to 5 years without clinical significance.

CONCLUSIONS AND CLINICAL RELEVANCE

The method of graft fixation did not yield a difference in clinical or radiographical outcome at 5 years. Results were excellent in both groups.

LEVEL OF EVIDENCE

I.

Creation of femoral tunnel by outside-in technique for ACL reconstruction: an analysis

PURPOSE

To study the outcome of ACL reconstruction by retrograde outside-in (OI) creation of femoral tunnel.

METHODS

ACL reconstruction was done in 41 cases by OI technique. The tip of 115° femoral guide was placed at posterior aspect of femoral foot print of ACL. Reaming was done from outside-in over guide pin. The length of femoral tunnel was obtained by measuring guide pin. The location of intra-articular femoral tunnel aperture and graft was recorded. Tibial tunnel was created with 50° guide placed at tibial foot print of ACL. Post-operative digital radiograph was taken. Antero-posterior view was used to calculate coronal inclination of femoral tunnel. On lateral view femoral tunnel location was marked in relation to the intersection of Blumensaat line and posterior femoral cortical line. Lysholm scoring and pivot shift test were performed at follow-up. Objective measurement of anterior tibial translation was done by rolimeter (aircast) at 1 year.

RESULTS

The mean femoral tunnel length recorded was 39.5 mm (±3.4). There was no incidence of femoral tunnel blow out or graft impingement. All cases had femoral tunnel aperture location posterior to posterior femoral cortical line and inferior to Blumensaat line. The mean coronal angle of femoral tunnel was 30.39° (±4.6). The mean preoperative Lysholm score of 53.5 (±13) increased to 95.2 (±3.5) 1 year after surgery. All the patients had full range of motion. The pivot shift test was negative and instrumented measurement of anterior translation of tibia was near normal in all cases.

CONCLUSION

OI technique of ACL reconstruction is a simple reproducible technique. The unconstrained placement and angling of femoral guide result in a femoral tunnel which is through footprint of ACL. The graft is placed very low, oblique and as posterior as possible on femoral side mimicking the native ACL.

LEVEL OF EVIDENCE

III.

The influence of femoral tunnel position in single-bundle ACL reconstruction on functional outcomes and return to sports

PURPOSE

The purpose of this study was to radiographically investigate the influence of femoral tunnel placement in ACL reconstruction on early outcomes and return to sports due to anatomic and nonanatomic positioning.

METHODS

A prospective study was conducted from 2008 to 2010, with 86 athletes who underwent ACL reconstruction between anteromedial (AM) footprint and high AM position. Knee functional outcomes (IKDC objective and subjective, Tegner score, and Lysholm scale) return to sports and complications were analyzed at 6- and 12-month follow-up.

RESULTS

At follow-up, it was observed that tunnel projection along Blumensaat's line was correlated with functional outcomes on Tegner scale (at 6 and 12 months) and IKDC subjective (at 12 months). There was a significant difference in mean tunnel projection along Blumensaat's line when analyzing return to sports (73 ± 1.4 and 79 ± 1.7 %, respectively, for projections on return vs. no return to sports, p = 0.02) and complications (73 ± 1.3 vs. 78 ± 1.6 %, respectively, for projections on no complications vs. complications, p = 0.03). No differences were stated on coronal view. These correlations between tunnel positioning on functional outcomes could not be explained by demographic or baseline characteristics.

CONCLUSION

The clinical relevance of this study is that tunnel positioning along AM footprint and high AM position represented by tunnel projection along Blumensaat's line is associated with early return to sports on previous Tegner level and better functional outcome in athletes.

Accuracy of a computer-assisted planning and placement system for anatomical femoral tunnel positioning in anterior cruciate ligament reconstruction

BACKGROUND

Femoral tunnel positioning is a difficult, but important factor in successful anterior cruciate ligament (ACL) reconstruction. Computer navigation can improve the anatomical planning procedure besides the tunnel placement procedure.

METHODS

The accuracy of the computer-assisted femoral tunnel positioning method for anatomical double bundle ACL-reconstruction with a three-dimensional template was determined with respect to both aspects for AM and PL bundles in 12 cadaveric knees.

RESULTS

The accuracy of the total tunnel positioning procedure was 2.7 mm (AM) and 3.2 mm (PL). These values consisted of the accuracies for planning (AM:2.9 mm; PL:3.2 mm) and for placement (about 0.4 mm). The template showed a systematic bias for the PL-position.

CONCLUSIONS

The computer-assisted templating method showed high accuracy for tunnel placement and has promising capacity for application in anatomical tunnel planning. Improvement of the template will result in an accurate and robust navigation system for femoral tunnel positioning in ACL-reconstruction.

Biomechanical comparison of different graft positions for single-bundle anterior cruciate ligament reconstruction

PURPOSE

Recent reports have highlighted the importance of an anatomic tunnel placement for anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to compare the effect of different tunnel positions for single-bundle ACL reconstruction on knee biomechanics.

METHODS

Sixteen fresh-frozen cadaver knees were used. In one group (n = 8), the following techniques were used for knee surgery: (1) anteromedial (AM) bundle reconstruction (AM-AM), (2) posterolateral (PL) bundle reconstruction (PL-PL) and (3) conventional vertical single-bundle reconstruction (PL-high AM). In the other group (n = 8), anatomic mid-position single-bundle reconstruction (MID-MID) was performed. A robotic/universal force-moment sensor system was used to test the knees. An anterior load of 89 N was applied for anterior tibial translation (ATT) at 0°, 15°, 30° and 60° of knee flexion. Subsequently, a combined rotatory load (5 Nm internal rotation and 7 Nm valgus moment) was applied at 0°, 15°, 30° and 45° of knee flexion. The ATT and in situ forces during the application of the external loads were measured.

RESULTS

Compared with the intact ACL, all reconstructed knees had a higher ATT under anterior load at all flexion angles and a lower in situ force during the anterior load at 60° of knee flexion. In the case of combined rotatory loading, the highest ATT was achieved with PL-high AM; the in situ force was most closely restored with MIDMID, and the in situ force was the highest AM-AM at each knee flexion angle.

CONCLUSION

Among the techniques, AM-AM afforded the highest in situ force and the least ATT.

Evaluating the tibial and femoral insertion site of the anterior cruciate ligament using an objective coordinate system: a cadaver study

PURPOSE

The purpose of this study was to evaluate the tibial and femoral insertion site of the anterior cruciate ligament (ACL) using an objective coordinate system in a cadaver study in order to confirm radiological assumptions of previous investigators who identified the tibial footprint (T) of the ACL on T (5.3; 5.5) and the femoral footprint (F) on F (2.9; 3.5).

METHODS

The tibial and femoral insertion site of the ACL was analysed on 30 human cadaver knee joints preserved according to the technique by Thiel. Thirty femora and tibiae were photographed under standardised methods and measured on a coordinate system twice by two examiners with respect to the ACL's footprint. We evaluated these measurements by use of the Cohen's kappa inter- and intraobserver coefficient for two observers.

RESULTS

The photographs and tibial and femoral measurements were achieved with an almost perfect and a substantial agreement of inter- and intraobserver coefficients. Further, we could demonstrate that assumptions of anatomic points in previous radiological investigations were correct.

CONCLUSIONS

Our findings confirmed the anatomic tibial and femoral ACL footprint of a previous investigation and further the reproducibility of our coordinate system as an objective method for graft placement evaluation.

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.

Drilling the femoral tunnel during ACL reconstruction: transtibial versus anteromedial portal techniques

Incorrect bone tunnel position, particularly on the femoral side, is a frequent cause of failed anterior cruciate ligament reconstruction. Several studies have reported that drilling the femoral tunnel through the anteromedial portal allows a more anatomical placement on the lateral femoral condyle and higher knee stability than does transtibial reconstruction.In the current study, the femoral tunnel was drilled with transtibial (n=6) and anteromedial (n=6) portal techniques in 12 cadaveric knees. With appropriate landmarks inserted into bone tunnels, the direction and length of the tunnels were determined on anteroposterior and lateral radiographs. Knee stability was evaluated with a KT1000 arthrometer (MEDmetric Corporation, San Diego, California) and pivot shift test, comparing the pre- and postoperative values of both techniques. Finally, all knees were dissected to enhance vision of the insertion of the reconstructed ligament. The anteromedial portal technique led to better placement of the femoral tunnel in the coronal and sagittal planes, with higher knee stability according to the pivot shift test but not the KT1000 arthrometer. Anatomical and clinical results reported in the literature on transtibial and anteromedial portal techniques are controversial, but most of studies report better results with the anteromedial portal technique, especially regarding rotational stability. The current cadaveric study showed that the anteromedial portal technique provided better tunnel placement on the lateral femoral condyle in the coronal and sagittal planes, with an improvement in the rotational stability of the knee.

Arthroscopic ACL reconstruction with reverse "Y"-plasty grafts and fixation in the femur with either a bioabsorbable interference screw or an Endobutton

We propose a new reverse "Y"-plasty graft for use in anterior cruciate ligament (ACL) reconstruction that involves double tibial tunnels and a single femoral tunnel. With this technique, the hamstrings were used as autografts and fixed separately with bioabsorbable interference screws (group A) or Endobuttons (group B) in femurs. A prospective series of 63 patients underwent primary reconstruction of the ACL; all procedures were performed by the same surgeon. Group A included 35 patients (22 male, 13 female), with a mean age of 25.5 (17-40) years, who were followed up for 28.5 (12-48) months. Group B included 28 patients (17 male, 11 female), with a mean age of 24.3 (18-38) years, who were followed up for 29.5 (12-46) months. Lysholm, International Knee Documentation Committee (IKDC) and Larson scoring were used to compare the therapeutic effects experienced at the knee. Lysholm scores were 93.26±2.67 (group A) and 93.81±2.42 (group B); Larson scores were 91.91±2.29 (group A) and 92.81±2.39 (group B); IKDC scores were 93.89±1.88 (group A) and 94.15±1.77 (group B). None of the scoring differences between groups were statistically significant (T(1)=0.849, P(1)=0.399, T(2)=1.506, P(2)=0.137, T(3)=0.560, P(3)=0.578). The Lachman test was negative in 46 patients (90.2%) and 51 knees, including 25 (89.3%) of the 28 knees in group A and 21 (91.3%) of the 23 knees in group B. Negative Pivot shift was present postoperatively in 49 knees of 51 patients (96.1%), including 27 (96.4%) of the 28 knees in group A and 22 (95.7%) of the 23 knees in group B. All of the patients in both groups achieved full extension and at least 135° of knee flexion. This novel technique involves the creation of double tibial tunnels and a single femoral tunnel. In the tibia, there was a bone bridge, ranging from 2 to 3mm, between the two bundles, which are tensioned at different degrees of flexion to maintain the stability of the knee. In the femur, the grafts were fixed with bioabsorbable interference screws or Endobuttons. The outcomes show that normal function and joint stability were achieved in both groups, as compared with preoperative measurements. Although the outcomes in group A (grafts fixed with the bioabsorbable interference screws in the femur) was better than those observed in group B (grafts fixed with Endobuttons), there was no statistical difference between the groups.

The use of intra-operative image intensifier control for the ACL surgeon

Tunnel placement during anterior cruciate ligament reconstruction surgery is an important factor in determining the outcome of surgery. Tibial and femoral tunnel placement depends on the experience of the operating surgeon in order to achieve an isometric graft position. We performed a case series to study how often tunnel placement was adequate, as perceived by the surgeon, and if intra-operative image guidance could improve tunnel position. Over 3 years, a single surgeon and his team operated on 55 patients using single bundle patellar tendon bone or hamstring graft. The surgeon placed the guidewires where he felt they would achieve an isometric graft position. A transtibial jig was used for femoral tunnel positioning. At each step, the guidewires were checked using an image intensifier and repositioned as necessary. The number of times that the guidewire position could be improved using the image intensifier was documented. Follow up was between 1 to 3 years. The tibial guidewire was repositioned in 13 out of 55 cases and the femoral guidewire in 16 out of 55 cases. Forty-five out of 55 patients returned to their pre injury state. There were no cases of graft failure in the follow up period. The study concludes that tunnel placement is not always successful despite the surgeon's perception of adequate placement. The use of an intra-operative image intensifier can help the surgeon to achieve accurate and reproducible tunnel placement in ACL reconstruction surgery. We recommend this technique to all surgeons carrying out such procedures.

The effect of femoral tunnel placement on ACL graft orientation and length during in vivo knee flexion

Anatomically placed grafts are believed to more closely restore the function of the ACL. This study measured the effect of femoral tunnel placement on graft orientation and length during weight-bearing flexion. Both knees of twelve patients where the graft was placed near the anteroproximal border of the ACL and ten where the graft was placed near the center of the ACL were imaged using MR. These images were used to create 3D models of the reconstructed and intact contralateral knees, including the attachment sites of the native ACL and graft. Next, patients were imaged using biplanar fluoroscopy while performing a quasi-static lunge. The models were registered to the fluoroscopic images to reproduce in vivo knee motion. From the relative motion of the attachment sites on the models, the length and orientation of the graft and native ACL were measured. Grafts placed anteroproximally on the femur were longer and more vertical than the native ACL in both the sagittal and coronal planes, while anatomically placed grafts more closely mimicked ACL motion. In full extension, the grafts placed anteroproximally were 12.3±5.2° (mean and 95%CI) more vertical than the native ACL in the sagittal plane, whereas the grafts placed anatomically were 2.9±3.7° less vertical. Grafts placed anteroproximally were up to 6±2 mm longer than the native ACL, while the anatomically placed grafts were a maximum of 2±2 mm longer. In conclusion, grafts placed anatomically more closely restored native ACL length and orientation. As a result, anatomic grafts are more likely to restore intact knee kinematics.

Development of a femoral template for computer-assisted tunnel placement in anatomical double-bundle ACL reconstruction

Femoral graft placement is an important factor in the success of anterior cruciate ligament (ACL) reconstruction. In addition to improving the accuracy of femoral tunnel placement, Computer Assisted Surgery (CAS) can be used to determine the anatomic location. This is achieved by using a 3D femoral template which indicates the position of the anatomical ACL center based on endoscopically measurable landmarks. This study describes the development and application of this method. The template is generated through statistical shape analysis of the ACL insertion, with respect to the anteromedial (AM) and posterolateral (PL) bundles. The ligament insertion data, together with the osteocartilage edge on the lateral notch, were mapped onto a cylinder fitted to the intercondylar notch surface (n = 33). Anatomic variation, in terms of standard variation of the positions of the ligament centers in the template, was within 2.2 mm. The resulting template was programmed in a computer-assisted navigation system for ACL replacement and its accuracy and precision were determined on 31 femora. It was found that with the navigation system the AM and PL tunnels could be positioned with an accuracy of 2.5 mm relative to the anatomic insertion centers; the precision was 2.4 mm. This system consists of a template that can easily be implemented in 3D computer navigation software. Requiring no preoperative images and planning, the system provides adequate accuracy and precision to position the entrance of the femoral tunnels for anatomical single- or double-bundle ACL reconstruction.

Impact of tibial and femoral tunnel position on clinical results after anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to correlate anatomic and nonanatomic tibial and femoral tunnel positions after anterior cruciate ligament (ACL) reconstruction with clinical outcome by use of bone-patellar tendon-bone (BPTB) single-bundle (SB) and semitendinosus-gracilis (STG) double-bundle (DB) techniques.

METHODS

The 3-dimensional computed tomography scans of 53 patients' knees (27 BPTB-SB and 26 STG-DB) were prepared and measured by 2 examiners according to their tibial and femoral tunnel positions. We evaluated these radiologic constructions and measurements by use of the Cohen κ interobserver and intraobserver coefficient for 2 observers. Patients undergoing both techniques were divided into anatomic and nonanatomic reconstructions according to the findings of Zantop and Petersen. We correlated anatomically and nonanatomically reconstructed patients with clinical outcome by the Tegner score, Western Ontario and McMaster Universities Osteoarthritis Index score, International Knee Documentation Committee score, KT-1000 arthrometer (MEDmetric, San Diego, CA), and pivot-shift test in both techniques.

RESULTS

The radiologic constructions and measurements of 53 computed tomography scans were achieved with a good agreement of interobserver and intraobserver coefficients for 2 observers. We found significantly superior clinical outcome in anatomic ACL reconstructions in both techniques in terms of higher clinical scores (Tegner and International Knee Documentation Committee), higher anterior posterior stability, and less pivot shift. We observed the best outcome in anatomic STG-DB reconstructions.

CONCLUSIONS

This investigation showed that better clinical results are associated with anatomic ACL reconstructions.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

ACL injury and reconstruction: Clinical related in vivo biomechanics

Several researchers including our group have shown that knee joint biomechanics are impaired after anterior cruciate ligament (ACL) injury, in terms of kinematics and neuromuscular control. Current ACL reconstruction techniques do not seem to fully restore these adaptations. Our research has demonstrated that after ACL reconstruction, excessive tibial rotation is still present in high-demanding activities that involve both anterior and rotational loading of the knee. These findings seem to persist regardless of the autograft selection for the ACL reconstruction. Our results also suggest an impairment of neuromuscular control after ACL reconstruction, although muscle strength may have been reinstated. These abnormal biomechanical patterns may lead to loading of cartilage areas, which are not commonly loaded in the healthy knee and longitudinally can lead to osteoarthritis. Muscle imbalance can also influence patients' optimal sports performance exposing them to increased possibility of knee re-injury. In this review, our recommendations point towards further experimental work with in vivo and in vitro studies, in order to assist in the development of new surgical procedures that could possibly replicate more closely the natural ACL anatomy and prevent future knee pathology.

IKDC or KOOS: which one captures symptoms and disabilities most important to patients who have undergone initial anterior cruciate ligament reconstruction?

BACKGROUND

Knee-specific patient-reported outcome measures are frequently used after anterior cruciate ligament reconstruction but little is known about whether they measure outcomes important to patients.

PURPOSE

The aim of this study was to identify which instrument, the Knee injury and Osteoarthritis Outcome Score (KOOS) or the International Knee Documentation Committee Subjective Knee Form (IKDC), captures symptoms and disabilities most important to patients who have undergone initial anterior cruciate ligament reconstruction.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Data were collected from 126 participants of an Internet knee forum. A self-reported online questionnaire was developed consisting of demographic and surgical data, the Tegner Activity Scale, and 49 consolidated items from the KOOS and the IKDC. Item importance, frequency, and frequency-importance product were calculated.

RESULTS

Seventy-eight percent of the items from the IKDC were experienced by more than half of the patients, compared with 57% from the KOOS. Items extracted from the Function in Sports/Recreation and Quality of Life KOOS subscales were highly important to this group of patients. For patients 12 months or more after anterior cruciate ligament reconstruction, 94% of the IKDC items had a frequency-importance product of 1 or less compared with 86% of the KOOS items.

CONCLUSION

Overall, the IKDC items outperformed the KOOS items on all of the 5 criteria with the exception of the frequency-importance product for patients who were 12 months after anterior cruciate ligament reconstruction. The KOOS Function in Sports/Recreation and Knee-Related Quality of Life subscales outperformed the IKDC for the total cohort as well as for male and female subgroups. However, differences in individual items were not always evident from either total scale or subscale ratings. Studies should use patient-reported outcomes that reflect patients' most important concerns and further prospective longitudinal research is required in this area.

Single-bundle anterior cruciate ligament reconstruction: a comparison of conventional, central, and horizontal single-bundle virtual graft positions

BACKGROUND

Conventional endoscopic single-bundle transtibial anterior cruciate ligament (ACL) reconstruction from the posterolateral tibial footprint to the anteromedial femoral footprint results in a vertical graft. A more oblique horizontal graft from the anteromedial tibial footprint to the posterolateral femoral footprint may offer a better alternative for all endoscopic ACL reconstruction.

HYPOTHESIS

When compared with a conventional ACL single-bundle position, the horizontal graft ACL position has more obliquity and so undergoes a greater change in length during anterior translation and internal rotation.

STUDY DESIGN

Controlled laboratory study.

METHODS

A computer navigation system was used to acquire kinematic data during a flexion-extension cycle and outline the anteromedial and posterolateral aspects of the tibial and femoral footprints on 5 fresh-frozen cadaveric knees. Three virtual graft positions were defined: conventional (posterolateral tibia-anteromedial femur), central, and horizontal (anteromedial tibia- posterolateral femur). After transection of the ACL, the obliquity, anisometry, absolute length change, and apparent strain were computed for each graft position during the Lachman test, the anterior drawer test, and internal rotation at 0 degrees and 30 degrees of flexion.

RESULTS

The horizontal position was more oblique than the other positions (P < .05). There were no differences in anisometry. The horizontal position elongated more than the other positions during the Lachman test (P < .05) and more than the conventional position during the anterior drawer test (P = .009). During internal rotation at 30 degrees flexion, the horizontal position elongated more than the other positions (P < .05). The central and horizontal positions had more apparent strain than that of the vertical position during the Lachman test and internal rotation (P < .05); no significant difference was found during the anterior drawer test.

CONCLUSION

In ACL-deficient cadaveric knees, the horizontal graft position has greater obliquity and so undergoes greater elongation without increased apparent strain when compared to the central graft position, in response to anterior translation and internal rotation maneuvers.

CLINICAL RELEVANCE

Horizontal graft placement of a single-bundle ACL may result in greater control of translation and rotation.

Radiographic identification of the primary posterolateral knee structures

BACKGROUND

It is often difficult to identify the attachment sites of the fibular collateral ligament, popliteus tendon, and popliteofibular ligament for chronic posterolateral knee injuries or during revision surgeries. Descriptions of radiographic landmarks for these attachment sites would assist in the intraoperative identification of their locations and also allow for postoperative assessment of the placement of reconstruction tunnels.

HYPOTHESIS

Identification of qualitative and quantitative radiographic landmarks for the attachments of the main posterolateral knee structures are reproducible among observers of various experience levels and allow for improved intraoperative and postoperative identification of these attachment sites.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Dissections were performed on 11 cadaveric knee specimens. The attachments and locations of the investigated structures were labeled with radiopaque markers. The positions of the attachments relative to other attachment sites, labeled bony landmarks, and superimposed reference lines were quantified on anteroposterior and lateral radiographs. Measurements were performed by 3 independent examiners. Intraobserver and interobserver reliability was determined using intraclass correlation coefficients.

RESULTS

Overall intraclass correlation coefficients for intraobserver reproducibility and interobserver reliability were calculated to be 0.981 and 0.983, respectively. On the anteroposterior view, the perpendicular distances from a line intersecting the femoral condyles to the popliteus tendon, proximal fibular collateral ligament, and lateral gastrocnemius tendon were 14.5, 27.1, and 34.5 mm, respectively. On the lateral view, the femoral attachments of the fibular collateral ligament, popliteus tendon, and lateral gastrocnemius tendon were 4.3, 12.2, and 13.1 mm, respectively, from the lateral epicondyle. In addition, the fibular collateral ligament and popliteus tendon were located within 1 mm of a reference line projected along the posterior femoral cortex distally, and also were located within the posteroinferior quadrant bound by the posterior femoral cortex extension reference line and another reference line perpendicular to it at the posterior margin of Blumensaat's line.

CONCLUSION

Comprehensive qualitative and quantitative guidelines for assessing posterolateral knee structures on both anteroposterior and lateral knee radiographs were described.

CLINICAL SIGNIFICANCE

This radiographic information regarding the attachment sites of posterolateral structures can serve as a valuable reference for preoperative, intraoperative, and postoperative assessments of surgical reconstructions.

Tunnel enlargement after double-bundle anterior cruciate ligament reconstruction: a prospective, randomized study

PURPOSE

The aim of this study was to compare tunnel enlargement in patients with double-bundle and single-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

Sixty patients were randomized by closed envelopes into 2 different groups of ACL reconstruction with hamstring tendons: double-bundle technique with bioabsorbable screw fixation (n = 35) and single-bundle technique with bioabsorbable screw fixation (n = 25). Magnetic resonance imaging evaluation was performed in 53 patients (88%) (32 in double-bundle group and 21 in single-bundle group) for a mean of 27 months' follow-up (range, 24 to 36 months). Tunnel enlargement was determined by digital measurement of the widths perpendicular to the long axis of the tunnels on an oblique coronal and sagittal plane. The magnetic resonance imaging measurements were compared with the intraoperative drill diameter.

RESULTS

No significant differences were found between the double-bundle group and the single-bundle group in tunnel enlargement on the femoral side. However, on the tibial side, tunnel enlargement was greater in the single-bundle group than in the double-bundle group in each tunnel (P = .051). In all knees, tunnel enlargement both on the tibial side and on the femoral side correlated significantly with the anterior and rotational laxity of the operated knee. In the double-bundle group, no tunnel communication between the anteromedial and posterolateral tunnels was seen in any of the patients on either the tibial side or femoral side.

CONCLUSIONS

This prospective, randomized study showed that our double-bundle ACL reconstruction technique results in less tunnel enlargement in each tunnel on the tibial side than the single-bundle technique with similar fixation methods, graft material, and rehabilitation. In addition, no tunnel communication was observed in the patients undergoing double-bundle ACL reconstruction. The clinical results were good in both groups. However, the patients who had more tunnel enlargement had significantly more anterior and rotational laxity of the operated knee as well.

LEVEL OF EVIDENCE

Level I, therapeutic randomized controlled trial.

ACL reconstruction: Can the transtibial technique achieve optimal tunnel positioning? A radiographic study

Placement of the femoral tunnel performing ACL reconstruction can be performed using a transtibial technique. Theoretically, this procedure bears the risk of a vertical placement of the femoral tunnel in the intercondylar notch. We assessed tunnel positioning radiographically using the transtibial technique. Postoperative anteroposterior and lateral knee radiographs in 30 patients/knees (19 men, 11 women) undergoing ACL reconstruction using a 4-strand single bundle hamstrings tendon graft by a single surgeon, using a standardized technique, were retrospectively evaluated. Mean age at the time of operation was 27 years (range 16-42). Two experienced independent orthopaedic fellows, not having participated in the management of those patients, performed the radiographic measurements. Mean graft inclination angle was 19 degrees (SD 2). In the sagittal plane the femoral tunnel was placed at 85% (SD 4), posteriorly across Blumensaat's line and the tibial tunnel at 43% (SD 3). Intraobserver Spearman-Brown coefficient was 0.78 and the intraclass correlation was 0.70 (substantial agreement). The values presented are consistent with optimal tunnel positioning according to anatomic and clinical studies. Standardized surgical technique and anatomical landmarks can achieve optimal tunnel positioning using the transtibial technique for ACL reconstruction.

Changes in the length of virtual anterior cruciate ligament fibers during stability testing: a comparison of conventional single-bundle reconstruction and native anterior cruciate ligament

BACKGROUND

Conventional tunnel positions for single-bundle (SB) transtibial anterior cruciate ligament (ACL) reconstruction are located in the posterolateral (PL) tibial footprint and the anteromedial (AM) femoral footprint, resulting in an anatomic mismatch graft that is more vertical than native fibers. This vertical mismatch position may significantly influence the ability of an ACL graft to stabilize the knee.

HYPOTHESIS

Anatomic ACL fibers undergo a greater change in length during anterior translation and internal rotation than a conventional SB reconstruction from the PL tibial footprint to the AM femoral footprint.

STUDY DESIGN

Controlled laboratory study.

METHODS

The Praxim ACL Surgetics navigation system was used to acquire kinematic data during a flexion/extension cycle and to register all points within the ACL footprint from 5 fresh-frozen cadaveric knees. Virtual fibers were placed in the center of the AM and PL bundles as well as central and conventional SB positions. After transection of the ACL, the absolute length change and apparent strain of the fibers were computed for each knee during the Lachman and anterior drawer tests and internal rotation at 0 degrees and 30 degrees of flexion.

RESULTS

Each of the anatomic fibers (AM, PL, and central) had more elongation and apparent strain than the conventional SB fiber during the Lachman maneuver. During the anterior drawer test, the AM and central (but not the PL) fibers lengthened significantly more and the AM had more apparent strain than the conventional SB fiber. During internal rotation at 0 degrees and 30 degrees of flexion, anatomic fibers elongated significantly more than the conventional fiber. Except for the AM fiber with the knee at full extension, apparent strain was greater in all anatomic fibers than in the conventional SB fiber during internal rotation maneuvers.

CONCLUSION

In ACL-deficient cadaveric knees, anatomic fibers undergo greater elongation and apparent strain in response to anterior translation and internal rotation maneuvers than a conventional SB graft. Because of their optimal orientation, anatomic fibers may resist pathologic anterior translation and internal rotation more than the conventional SB position.

CLINICAL RELEVANCE

Conventional placement of a single-bundle graft results in suboptimal changes in fiber length and strain, suggesting that alternatives such as anatomic placement of an SB graft or double-bundle reconstruction may result in greater control of translation and rotation.

Comparison of 3-dimensional obliquity and anisometric characteristics of anterior cruciate ligament graft positions using surgical navigation

BACKGROUND

Surgical navigation allows continuous intraoperative monitoring of ACL graft anisometry and 3-dimensional obliquity. However, normative anisometry and obliquity measurements for different single-bundle anterior cruciate ligament graft positions are not well described.

HYPOTHESIS

ACL Grafts placed in anteromedial and posterolateral bundle positions will have distinct anisometric profiles and 3-dimensional obliquities. A graft placed centrally in anterior cruciate ligament insertion sites will have different obliquity and anisometry than a conventional (single-bundle) graft extending from the tibia's posterolateral aspect to the femur's anteromedial aspect.

STUDY DESIGN

Controlled laboratory study.

METHODS

Five cadaveric knees were tested. A surgical navigation system was used to create 4 virtual graft positions in the anterior cruciate ligament footprint: (1) anteromedial, (2) posterolateral, (3) central, and (4) posterolateral tibia to anteromedial femur (conventional). Obliquity at various flexion angles and anisometry of each virtual graft's central fiber were determined.

RESULTS

Anteromedial and posterolateral fibers are relatively parallel up to 30 degrees of flexion. At higher degrees of flexion, the anteromedial position is more oblique in the sagittal plane, while the posterolateral position is more oblique in the axial plane. The conventional single-bundle position is significantly more vertical than the central position in multiple planes throughout the range of motion. The anteromedial fiber is most isometric, while the posterolateral fiber is the least isometric at all flexion angles. There is no significant difference in the anisometry between the central or conventional positions at any flexion angle. The posterolateral, central, and conventional fibers were longest at full extension and slackened with progressive flexion.

CONCLUSION

Anteromedial and posterolateral graft positions can be distinguished by sagittal and axial plane obliquity at flexion angles >30 degrees and by anisometry measurements. Conventional positioning produces a relatively vertical graft placement compared with the central position but has similar anisometry characteristics. Our data suggest that posterolateral, central, and conventional grafts should be fixed at or near full extension to avoid excessive tightening during motion.

CLINICAL RELEVANCE

This study provides anisometry and 3-dimensional obliquity data for various graft positions using surgical navigation. The failure of single-bundle anterior cruciate ligament reconstruction to restore intact knee kinematics may be partly due to the relative vertical placement of conventional grafts compared with the central anterior cruciate ligament footprint position.

Reconstruction technique affects femoral tunnel placement in ACL reconstruction

Grafts placed too anteriorly on the femur are reportedly a common cause of failure in anterior cruciate ligament reconstruction. Some studies suggest more anatomic femoral tunnel placement improves kinematics. The ability of the transtibial technique and a tibial tunnel-independent technique (placed transfemorally outside-in) to place the guide pin near the center of the femoral attachment of the anterior cruciate ligament was compared in 12 cadavers. After arthroscopic placement of the guide pins, the femur was dissected and the three-dimensional geometry of the femur, anterior cruciate ligament footprint, and positions of each guide pin were measured. The transtibial guide-pin placement was 7.9 +/- 2.2 mm from the center of the footprint (near its anterior border), whereas the independent technique positioned the guide pin 1.9 +/- 1.0 mm from the center. The center of the footprint was within 2 mm of an anteroposterior line through the most posterior border of the femoral cartilage in the notch and a proximodistal line through the proximal margin of the cartilage at the capsular reflection. More accurate placement of the femoral tunnel might reduce the incidence of graft failure and might reduce long-term degeneration observed after reconstruction although both would require clinical confirmation.