Anatomic double-bundle anterior cruciate ligament reconstruction

Anatomical Anterior Cruciate Ligament Reconstruction with Hamstring Tendon Autografts: A Comparative Study of Three Different Techniques

The ideal procedure for anterior cruciate ligament (ACL) reconstruction is one that can achieve anatomical restoration for a better ACL function. This retrospective comparative study was conducted to evaluate the objective and subjective clinical results of the conventional single-bundle femoral round (SBR) tunnel technique, the single-bundle femoral oval (SBO) tunnel technique, and the double-bundle (DB) surgical technique for anatomical ACL reconstruction with hamstring tendon autografts. Patients who underwent the SBO, SBR, and DB ACL reconstructions from January 2016 to August 2017 were included in this study. A total of 163 patients underwent different surgical techniques; 41 patients underwent the SBO procedure, 78 patients received SBR, and the remaining 44 patients underwent the DB procedure. The Lachman's test, pivot-shift test, Lysholm's score, International Knee Documentation Committee (IKDC) score, and Tegner's score were compared among groups postoperatively. KT-1000 was used to measure the anterior laxity of the knee. Magnetic resonance imaging was used to compare the ACL graft maturity. Second-look arthroscopy was conducted to compare the graft status and synovial coverage. Significant differences among groups were found with respect to the Lysholm's score, Tegner's score, and IKDC score. Patients in the SBO and DB groups acquired higher functional scores than the SBR group. More patients with positive pivot-shift test were observed in the SBR group than other groups at 12- and 24-month postoperative follow-ups. The postoperative KT-1000 was better in the SBO and DB groups than in the SBR group. The mean signal/noise quotient (SNQ) of the SBO group was 2.70 ± 0.92, significantly lower than 3.58 ± 1.21 of the SBR group. Despite a higher proportion of patients with grade B or C synovial coverage and partial graft injury found in the SBR group, there were no significant differences among the groups. The SBO and DB technique achieved better clinical results than the SBR technique. The SBO technique was indeed an ideal surgical procedure for ACL reconstruction provided that the shortcoming of DB technique must be taken into account. This is a Level III, retrospective comparative study.

[Comparison of femoral oval tunnel technique and round tunnel technique in single-bundle anterior cruciate ligament reconstruction]

OBJECTIVE

To evaluate the effectiveness of femoral oval tunnel technique versus round tunnel technique in single-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

Between March 2016 and February 2018, 125 patients who underwent anatomical single-bundle ACL reconstruction with hamstring tendon and met the inclusive criteria were included in the retrospective study. Of the included patients, 43 patients underwent ACL reconstruction using oval tunnel technique (group A) and 82 patients with round tunnel technique (group B). There was no significant difference between the two groups in terms of age, gender, body mass index, the interval between injury and operation, the injured side, the cause of injury, and preoperative Lysholm score, International Knee Documentation Committee (IKDC) score, Tegner score, and the outcome of KT-1000 measurement ( P>0.05). At 3, 6, 12, and 24 months after operation, the knee function scores (Lysholm score, IKDC score, Tegner score) were recorded; and KT-1000 was used to evaluate the knee stability. The position and shape of the tunnels were evaluated by the three-dimensional CT (3D-CT) at 1 day after operation; and MRI was performed at 6, 12, and 24 months to calculate the signal/noise quotient (SNQ) of ACL grafts. Secondary arthroscopy was conducted to estimate the graft status, synovial coverage, and tension.

RESULTS

All patients were followed up 12-26 months (mean, 23 months). Two patients in group A and 5 patients in group B presented with redness and swelling of the surgical site, 1 patient in group B sustained a tibial tunnel fracture, and 1 patient in group A had postoperative stiffness. The Lysholm score, IKDC score, and Tegner score were significantly higher in group A than in group B at the different time points ( P<0.05) except for the Tegner score at 3 months. The outcomes of KT-1000 measurement were significantly lower in group A than in group B ( P<0.05). The entrances of the femoral tunnel and tibial tunnel in both groups were within the ACL anatomical footprint confirmed by 3D-CT. No re-rupture of ACL occurred confirmed by the MRI. There was no significant difference in SNQs of the middle and distal grafts between the two groups at 6 months ( P>0.05), whereas the SNQ of the proximal grafts in group A was significantly lower than that in group B ( P<0.05). The SNQs of the proximal, middle, and distal grafts in group A were significantly lower than those in group B at 12 and 24 months after operation ( P<0.05). Twenty-one patients in group A and 38 patients in group B underwent secondary arthroscopy and the results showed no significant difference in graft status, synovial coverage, and tension between the two groups ( P>0.05).

CONCLUSION

The effectiveness and graft maturity of the femoral oval tunnel technique were superior to the round tunnel technique. The single-bundle ACL reconstruction with femoral oval tunnel technique can obtain a better knee function.

Tensile properties of a split quadriceps graft for ACL reconstruction

PURPOSE

Anatomic double-bundle ACL reconstruction can be performed using different grafts, such as quadriceps tendon. Grafts can be split in either coronal or sagittal planes to approximate the two bundles of the native ACL, but it is unknown whether a difference exists in the graft tensile properties depending on splitting plane. The purpose of this study was to evaluate the tensile properties of split human quadriceps tendon-bone grafts.

METHODS

Twenty full-thickness quadriceps tendon-bone grafts were prepared to mimic grafts for double-bundle ACL reconstruction. Ten grafts were split in the sagittal plane, and ten were split in the coronal plane. Each graft underwent cyclic creep testing and load-to-failure testing to compare creep, ultimate load, ultimate elongation, stiffness, and tangent modulus between splitting planes. All parameters were compared between splitting groups (significance p < 0.05).

RESULTS

Lateral halves of grafts split in the sagittal plane exhibited a percent creep of 42.5 ± 12.4 %, ultimate load of 445 ± 210 N, ultimate elongation of 7.3 ± 1.9 mm, stiffness of 75.7 ± 19.9 N/mm, and tangent modulus of 174.0 ± 99.8 MPa. No differences were found between halves within split tendons or between splitting planes (n.s.).

CONCLUSIONS

Overall, splitting quadriceps tendon grafts for anatomic double-bundle ACL reconstruction results in similar tensile properties regardless of splitting plane. Surgeons can split quadriceps tendon in either splitting plane, but should take care to preserve fibres as much as possible. This study provides data that support the use of both coronal and sagittal splits of quadriceps tendons for anatomic double-bundle ACL reconstruction.

The anatomy of the anterior cruciate ligament and its relevance to the technique of reconstruction

Anterior cruciate ligament (ACL) reconstruction is commonly performed and has been for many years. Despite this, the technical details related to ACL anatomy, such as tunnel placement, are still a topic for debate. In this paper, we introduce the flat ribbon concept of the anatomy of the ACL, and its relevance to clinical practice.

Cite this article: Bone Joint J 2016;98-B:1020–6.

Increased risk of revision after anteromedial compared with transtibial drilling of the femoral tunnel during primary anterior cruciate ligament reconstruction: results from the Danish Knee Ligament Reconstruction Register

PURPOSE

The goal was to study revision rates and clinical outcome after anterior cruciate ligament (ACL) reconstruction using the anteromedial (AM) technique versus the transtibial (TT) technique for femoral drill hole placement.

METHODS

A total of 9,239 primary ACL reconstruction procedures were registered in the Danish Knee Ligament Reconstruction Register between January 2007 and December 2010. The failure of the 2 different femoral drilling techniques was determined using revision ACL reconstruction as the primary endpoint. As secondary endpoints, we used the pivot-shift test and instrumented objective test as well as patient-reported outcome, registered in the Danish Knee Ligament Reconstruction Register. Relative risks (RRs) with 95% confidence intervals (CI) were calculated.

RESULTS

We identified 1,945 AM and 6,430 TT primary ACL procedures. The cumulative revision rates for ACL reconstruction after 4 years with the AM and TT techniques were 5.16% (95% CI: 3.61%, 7.34%) and 3.20% (95% CI: 2.51%, 4.08%), respectively. The adjusted overall RR for revision ACL surgery in the AM group was 2.04 (95% CI: 1.39, 2.99), compared with the TT group. Use of the AM technique increased from 13% of all operations in 2007 to 40% in 2010. AM technique was further associated with increased RRs of positive pivot shift of 2.86 (95% CI: 2.40, 3.41) and sagittal instability of 3.70 (95% CI: 3.09, 4.43), compared with the TT technique.

CONCLUSIONS

This study found an increased risk of revision ACL surgery when using the AM technique for femoral drill hole placement, compared with the TT technique, in the crude data as well as the stratified and adjusted data. Our finding could be explained by technical failures resulting from introduction of a new and more complex procedure or by the hypothesis put forward in prior studies that compared with a nonanatomic graft placement, a greater force is carried by the anatomic ACL reconstruction and, hence, there is a concomitant higher risk of ACL rupture.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Biomechanics of the human triple-bundle anterior cruciate ligament

PURPOSE

To investigate the biomechanics of the intermediate (IM), anteromedial (AM), and posterolateral (PL) bundles in the human anterior cruciate ligament (ACL).

METHODS

Eighteen human cadaveric knees were tested with a robotic/universal force-moment sensor testing system. Anterior tibial translation (ATT) was determined under an 89-N anterior tibial load. Coupled ATT was determined under a combined rotatory load of 7-Nm valgus and 5-Nm internal rotation torque (pivot moment). Each bundle's in situ forces were measured under identical external loading conditions.

RESULTS

Under anterior load, the PL bundle's in situ force was highest at 0° and decreased during flexion. Under the anterior load, the AM bundle's in situ force was significantly higher than the IM and PL bundles' force at 15°, 30°, and 60°. Under the pivot moment, the AM bundle's in situ force was significantly higher than the PL and IM bundles' force at 0° and 15°, and the IM bundle had the lowest in situ force at 0° but higher in situ force than the AM and PL bundles at 30° and 45°. IM and AM bundle removal increased ATT under the anterior load at all angles. Cutting the PL bundle after IM and AM bundle removal (whole ACL removal) significantly increased ATT under the anterior load at 0°, 15°, and 30° of knee flexion and increased coupled ATT under the pivot moment at 0° and 15°.

CONCLUSIONS

The biomechanical role of each of the 3 ACL bundles (AM, IM, and PL) was measured with a robotic/universal force-moment sensor testing system. The AM bundle stabilized the knee against both the anterior and rotatory loads. The PL bundle stabilized the knee especially near full extension. The IM bundle supported the AM and PL bundles through all flexion angles, especially from 30° to 45°, against the rotatory load.

CLINICAL RELEVANCE

Knowledge of functions of the different ACL bundles will help improve ACL reconstruction techniques to enable restoration of normal knee function.

Magnetic resonance imaging evaluation of knee kinematics after anterior cruciate ligament reconstruction with anteromedial and transtibial femoral tunnel drilling techniques

PURPOSE

The purpose of this study was to use magnetic resonance (MR) imaging to evaluate the translational and rotational kinematics of anterior cruciate ligament (ACL) reconstructed knees with transtibial (TT) and anteromedial (AM) femoral tunnel drilling.

METHODS

ACL reconstruction was performed in 21 subjects: 12 with AM drilling (5 men and 7 women; mean age, 33 ± 9 years; imaged 18 ± 5 months after surgery) and 9 with TT drilling (5 men and 4 women; mean age, 32 ± 9 years; imaged 12 ± 8 months after surgery). Three-tesla MR imaging was obtained bilaterally at extension and 30° to 40° of flexion under simulated loading (125 N). MR images were segmented and kinematic calculations done with in-house MATLAB software (The MathWorks, Natick, MA). Translation and rotation of the tibia and the tibiofemoral contact area were measured. Statistical analysis treated reconstructed and contralateral knees as independent groups. Reconstructed groups were compared with analysis of covariance using contralateral knees as baseline. P < .05 indicated significance.

RESULTS

All kinematic measures in the AM group were similar to contralateral knees. The TT group showed significantly more total tibial rotation than contralateral knees (TT, 8.4° ± 3.9°; contralateral, 2.9° ± 6.8°) (P = .03), whereas the AM group did not (AM, 3.1° ± 5.6°; contralateral, 2.3° ± 5.4°) (P = .36). At knee extension, the tibia was more externally rotated in the TT group than in controls. Medial tibial translation was greater in the TT group than in controls. The AM group showed increased contact area in the lateral compartment compared with controls; no differences were seen in the TT group.

CONCLUSIONS

Using an MR-based approach, we found that knee kinematics were better restored with the AM femoral tunnel drilling ACL reconstruction than with the TT femoral tunnel drilling approach, which resulted in increased knee laxity. Our in vivo results support previous cadaveric and clinical studies that have found AM ACL reconstruction to restore anatomy and stability better than the TT approach. However, the clinical significance of increased contact area in the AM group remains unclear.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Association between intercondylar notch narrowing and bilateral anterior cruciate ligament injuries in athletes

BACKGROUND

Intercondylar notch narrowing is a risk factor for anterior cruciate ligament (ACL) injuries, but it is unclear whether a narrow intercondylar notch correlates with bilateral ACL injuries.

PURPOSE

To determine whether a narrow intercondylar notch is associated with bilateral ACL knee injuries in athletes, using magnetic resonance imaging (MRI) and radiography to investigate the notch size.

STUDY DESIGN

A retrospective case-control study.

METHODS

This was a comparative cohort study on 50 subjects of which 25 patients with sport trauma-associated bilateral ACL injuries, 30 with unilateral ACL injuries, and 20 healthy subjects. The notch width index (NWI) was measured as the ratio of the width of the intercondylar notch to the femoral condylar width on radiography and the MRI slice containing the region near the ACL attachment site on the femoral side (NWI-A) and on the following posterior slice (NWI-P).

RESULTS

The mean NWI values on radiography were 0.257 (SD 0.040), 0.332 (SD 0.036), and 0.341 (SD 0.027) in the bilateral, unilateral, and control groups, respectively, with significant differences between the bilateral and unilateral groups and the bilateral and healthy groups. On MRI, the mean NWI-A values were 0.236 (SD 0.025), 0.243 (SD 0.048), and 0.266 (SD 0.030), respectively, with a significant difference between the bilateral and healthy groups. The mean NWI-P values were 0.239 (SD 0.021), 0.258 (SD 0.038), and 0.273 (SD 0.033), respectively, with significant differences between the bilateral and unilateral groups and the unilateral and healthy groups. A cutoff value of 0.25 for NWI-P gave an odds ratio of 22.667 for the risk of developing bilateral ACL knee injuries.

CONCLUSIONS

The intercondylar notch was significantly narrower in subjects with bilateral ACL injuries than in healthy subjects. NWI measurement using coronal MRI is useful for judging intercondylar notch narrowing. The risk for ACL injuries is very high when NWI is ≤0.25. Preventive measures for the unaffected knee are required for patients with a narrow intercondylar notch.