Current concepts in anatomic single- and double-bundle anterior cruciate ligament reconstruction

Trends in Primary Anatomical Single-Bundle Anterior Cruciate Ligament Reconstruction Practice in Adult Patients Prevalent Among Arthroscopy Surgeons of Six Southern States of India

BACKGROUND

Although guidelines from multiple scientific studies decide the general trend in ACLR practice, there is often a variation between scientific guidelines and actual practice.

METHODS

A 17-member committee comprised of sports surgeons with experience of a minimum of 10 years of arthroscopy surgery finalized a survey questionnaire consisting of concepts in ACL tear management and perioperative trends, intraoperative and post-operative practices regarding single-bundle anatomic ACLR. The survey questionnaire was mailed to 584 registered sports surgeons in six states of south India. A single, non-modifiable response was collected from each member and analyzed.

RESULTS

324 responses were received out of 584 members. A strong consensus was present regarding Hamstring tendons preference for ACLR, graft diameter ≥ 7.5 mm, viewing femoral footprint through the anterolateral portal, drilling femoral tunnel from anteromedial portal guided by ridges and remnants of femoral footprint using a freehand technique, suspensory devices to fix the graft in femur and interference screw in the tibia and post-operative bracing. A broad consensus was achieved in using a brace to minimize symptoms of instability of an ACL tear and antibiotic soaking of graft. There was no consensus regarding the timing of ACLR, preferred graft in athletes, pre-tensioning, extra-articular procedure, and return to sports. There was disagreement over hybrid tibial fixation and suture tapes to augment graft.

CONCLUSION

Diverse practices continue to prevail in the management of ACL injuries. However, some of the consensuses reached in this survey match global practices. Contrasting or inconclusive practices should be explored for potential future research.

Medial and lateral meniscus have a different role in kinematics of the ACL-deficient knee: a systematic review

Importance

Meniscal tears are frequently associated with anterior cruciate ligament (ACL) injury and the correct management of this kind of lesion during ACL-reconstruction procedure is critical for the restoration of knee kinematics. Although the importance of meniscus in knee biomechanics is generally accepted, the influence of medial and lateral meniscus in stability of ACL-deficient knee is still unclear.

Objective

The aim of this study was to review literature, which analysed effects in cadaveric specimens of meniscal tear and meniscectomy of medial and lateral meniscus on laxity in the ACL-deficient knee.

Evidence review

Authors performed a systematic search for cadaveric studies analysing the effect of medial and lateral meniscus tears or resection on kinematics of ACL-deficient knee. Extracted data included year of publications, number of human cadaver knee specimens, description of apparatus testing and instrumented kinematic evaluation, testing protocol and results.

Findings

Authors identified 18 studies that met inclusion and exclusion criteria of current review. The major finding of the review was that the works included reported a difference role of medial and lateral meniscus in restraining ACL-deficient knee laxity. Medial meniscus tear or resection resulted in a significant increase of anterior tibial displacement. Lateral meniscus lesions or meniscectomy on the other hand significantly increased rotation and translation under a coupled valgus stress and internal-rotation torque/pivot shift test.

Conclusions

Medial and lateral meniscus have a different role in stabilising the ACL-deficient knee: while the medial meniscus functions as a critical secondary stabilisers of anterior tibial translation under an anterior/posterior load, lateral meniscus appears to be a more important restraint of rotational and dynamic laxity.

Level of evidence

Level IV, systematic review of level I–IV studies.

Fibrin clot prevents bone tunnel enlargement after ACL reconstruction with allograft

PURPOSE

Bone tunnel enlargement is a feared complication after ACL reconstruction. The aim of this study was to evaluate whether adding a fibrin clot to the allograft for anatomic single-bundle ACL reconstruction would reduce tunnel widening.

METHODS

Fifty patients who underwent anatomic single-bundle ACL reconstruction were included. Twenty-five patients received an allograft alone, and 25 patients received an allograft with fibrin clot. All patients underwent standard plain anteroposterior and lateral radiographs of the operated knee immediately after surgery and at 1-year follow-up. The size of the tunnels was measured at both time points to calculate tunnel widening. Tunnel widening at 1 year was compared between the allograft and the allograft + fibrin clot group.

RESULTS

There was significantly less tunnel widening in the allograft + fibrin clot group for the femoral tunnel width in the middle and distal portion of the tunnel and for the tibial tunnel width in the proximal and distal portions, as compared to the allograft only group.

CONCLUSION

Adding a fibrin clot to the allograft in anatomic single-bundle ACL reconstruction reduces the amount of tunnel widening at 1-year follow-up. Reducing tunnel widening may positively affect outcomes after ACL surgery and may prevent inadequate bone stock during ACL revision procedures.

LEVEL OF EVIDENCE

Case-control study, Level III.

The effect of notchplasty on tunnel widening in anterior cruciate ligament reconstruction

PURPOSE

To investigate changes in femoral tunnel diameter, dimension, and volume after anterior cruciate ligament reconstruction with notchplasty.

METHODS

Porcine knee specimens were divided into 2 groups of 10 specimens each. Group A did not receive notchplasty. A 2-mm notchplasty was conducted in group B. Seven-millimeter-diameter femoral tunnels were drilled and a doubled flexor digitorum profundus tendon was inserted and fixed with an EndoButton (Smith & Nephew, Andover, MA) in each knee specimen. Samples were mounted on a materials testing machine. Each group was preloaded at 10 N and subjected to 20 loading cycles (between 0 and 40 N), followed by 1,000 loading cycles in the elastic region (between 10 and 150 N). High-resolution computed tomography with 1.0-mm slices was conducted with all samples before and after testing. A 3-dimensional model was constructed to evaluate the degree of the tunnel change.

RESULTS

In group B the mean longest diameter and dimension of the femoral tunnel significantly increased after the test (P = .005 and P = .001, respectively). The volumetric loss of bony structure after the test in group B was significantly greater than that in group A (P = .039). Meanwhile, no significant difference was found before and after the test in terms of tunnel diameter, dimension, and volumetric loss around the tunnel in group A.

CONCLUSIONS

The intra-articular orifice of the femoral tunnel was enlarged after the uniaxial cyclic loading test after notchplasty. An enlarged tunnel orifice may lead to a discrepancy between the tunnel and the graft at the tunnel aperture.

CLINICAL RELEVANCE

The data may have an implication that suspensory fixation with a notchplasty has a negative effect on the full graft accommodation at the tunnel aperture. Aperture widening may affect graft positioning, leading to subtle changes in graft biomechanics and laxity.

The effect of notchplasty in anterior cruciate ligament reconstruction: a biomechanical study in the porcine knee

INTRODUCTION

Notchplasty is frequently performed by many orthopaedic surgeons during anterior cruciate ligament (ACL) reconstruction. The effect of notchplasty on tunnel placement and knee biomechanics with ACL reconstruction is not known.

METHODS

Twelve (n = 12) porcine knees were tested using a robotic testing system. Four knee states were compared: (1) intact ACL, (2) ACL-deficient, (3) anatomic single bundle (SB) ACL reconstruction and (4) anatomic SB ACL reconstruction with a 5-mm notchplasty. The graft was fixed at 60° of flexion (full extension of porcine knee is 30°) with an 80-N tension. The knees were subjected to two loading conditions: an 89-N anterior tibial load (ATT) and 4 Nm internal (IR) and external tibial (ER) rotational torques. The kinematics and in situ force obtained from the different knee conditions were compared.

RESULTS

There were no significant differences between pre- and post-notchplasty in the ER at 30° and 60° of knee flexion (n.s.). However, a significant difference was found between pre- and post-notchplasty in ATT at 30° and 60° of flexion (p < 0.05). The in situ force in the anatomic SB reconstruction with notchplasty was significant lower than the intact and anatomic reconstructed ACL pre-notchplasty at 30°, 60° and 90° of knee flexion (p < 0.05). In response to the IR tibial torque, there were significant differences between pre- and post-notchplasty in IR at 60° (p < 0.05) of knee flexion.

CONCLUSION

Notchplasty had greater effect on anterior stability than rotational stability. This change in knee kinematics could be detrimental to a healing bone graft, ligamentization and could lead to failure of the reconstruction in early post-operative period.

Failure of anterior cruciate ligament reconstruction

Failure after anterior cruciate ligament reconstruction is a potentially devastating event that affects a predominantly young and active population. This review article provides a comprehensive analysis of the potential causes of failure, including graft failure, loss of motion, extensor mechanism dysfunction, osteoarthritis, and infection. The etiology of graft failure is discussed in detail with a particular emphasis on failure after anatomic anterior cruciate ligament reconstruction.

Double-bundle depiction of the anterior cruciate ligament at 3 Tesla

INTRODUCTION

Magnetic resonance imaging on 3 Tesla (3T MRI) with arthroscopic correlation has proven to adequately identify the anteromedial bundle (AMB) and posterolateral bundle (PLB) in cadaver knees. The purpose of this study was to describe the depiction of ACL bundle anatomy on 3T MRI in daily practice.

METHODS

In a retrospective cohort study, we included 50 consecutive patients who underwent standard 3T MRI of the knee and had an intact ACL. Two musculoskeletal radiologists independently reviewed all scans for depiction of ACL bundle anatomy using standardized forms. Descriptive statistics were used.

RESULTS

Twenty-three right knees (46%) and 27 left knees (54%) were included in the study. Mean age of the patients was 35 years (range 12 to 68 years); 37 patients were male (74%). ACL bundle anatomy was best depicted in the axial plane in 44 knees (88%) and in the coronal plane in six knees (12%). Two bundles were seen in 47 knees (94%). The AMB was completely seen in 45 knees (90%). The PLB was completely seen in 40 knees (80%). Both bundles were completely seen in 37 knees (76%).

CONCLUSIONS

The double-bundle anatomy of the ACL is visualized in 94% of patients on 3T MRI. Because of potentially associated clinical benefits, we advocate to report separately on the anteromedial bundle and posterolateral bundle in case of anterior cruciate ligament injury of the knee.

Simulation of Anterior Cruciate Ligament Deficiency in a Musculoskeletal Model with Anatomical Knees

Abnormal knee kinematics and meniscus injury resulting from anterior cruciate ligament (ACL) deficiency are often implicated in joint degeneration even though changes in tibio-femoral contact location after injury are small, typically only a few millimeters. Ligament reconstruction surgery does not significantly reduce the incidence of early onset osteoarthritis. Increased knowledge of knee contact mechanics would increase our understanding of the effects of ACL injury and help guide ACL reconstruction methods. Presented here is a cadaver specific computational knee model combined with a body-level musculoskeletal model from a subject of similar height and weight as the cadaver donor. The knee model was developed in the multi-body framework and includes representation of the menisci. Experimental body-level measurements provided input to the musculoskeletal model. The location of tibio-menisco-femoral contact as well as contact pressures were compared for models with an intact ACL, partial ACL transection (posterolateral bundle transection), and full ACL transection during a muscle driven forward dynamics simulation of a dual limb squat. During the squat, small changes in femur motion relative to the tibia for both partial and full ACL transection push the lateral meniscus in the posterior direction at extension. The central-anterior region of the lateral meniscus then becomes “wedged” between the tibia and femur during knee flexion. This “wedging” effect does not occur for the intact knee. Peak contact pressure and contact locations are similar for the partial tear and complete ACL transection during the deep flexion portion of the squat, particularly on the lateral side. The tibio-femoral contact location on the tibia plateau shifts slightly to the posterior and lateral direction with ACL transection.