Reconstruction of the Posterolateral Corner After Sequential Sectioning Restores Knee Kinematics

Anterior cruciate ligament failure and management

Anterior cruciate ligament (ACL) reconstruction failure can be defined as abnormal knee function due to graft insufficiency with abnormal laxity or failure to recreate a functional knee according to the expected outcome. Traumatic ruptures have been reported as the most common reason for failure. They are followed by technical errors, missed concomitant knee injuries, and biological failures. An in-depth preoperative examination that includes a medical history, clinical examinations, advanced imaging, and other appropriate methods is of utmost importance. There is still no consensus as to the ideal graft, but autografts are the favorite choice even in ACL revision. Concomitant meniscal treatment, ligamentous reconstruction, and osteotomies can be performed in the same surgical session to remove anatomical or biomechanical risk factors for the failure. Patient expectations should be managed since outcomes after ACL revision are not as good as those following primary ACL reconstruction.

Minimizing the risk of graft failure after anterior cruciate ligament reconstruction in athletes. A narrative review of the current evidence

Anterior cruciate ligament (ACL) tear is one of the most common sport-related injuries and the request for ACL reconstructions is increasing nowadays. Unfortunately, ACL graft failures are reported in up to 34.2% in athletes, representing a traumatic and career-threatening event. It can be convenient to understand the various risk factors for ACL failure, in order to properly inform the patients about the expected outcomes and to minimize the chance of poor results. In literature, a multitude of studies have been performed on the failure risks after ACL reconstruction, but the huge amount of data may generate much confusion.The aim of this review is to resume the data collected from literature on the risk of graft failure after ACL reconstruction in athletes, focusing on the following three key points: individuate the predisposing factors to ACL reconstruction failure, analyze surgical aspects which may have significant impact on outcomes, highlight the current criteria regarding safe return to sport after ACL reconstruction.

Biomechanical Assessment of Knee Laxity After a Novel Posterolateral Corner Reconstruction Technique

BACKGROUND

Different techniques to restore knee stability after posterolateral corner (PLC) injury have been described. The original anatomic PLC reconstruction uses 2 separate allografts to reconstruct the PLC. Access to allograft tissue continues to be a significant limitation of this technique, which led to the development of a modified anatomic approach utilizing a single autologous semitendinosus graft fixed on the tibia with an adjustable suspensory loop to enable differential tensioning of the PLC components.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the modified anatomic technique with the original anatomic reconstruction in terms of varus and external rotatory laxity in a cadaveric biomechanical model. The hypothesis was that both techniques would restore varus and external rotatory laxity after a simulated complete PLC injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight pairs of fresh-frozen cadaveric knee specimens were tested to compare the 2 techniques. Varus and external tibial rotation laxity of the knee were measured while applying 10-N·m varus and 5-N·m external rotatory torques at 0°, 30°, 60°, and 90° of flexion. These measurements were tested under 3 conditions: (1) intact fibular collateral ligament, popliteal tendon, and popliteofibular ligament; (2) complete transection of the fibular collateral ligament, popliteal tendon, and popliteofibular ligament; (3) after PLC reconstruction with either the modified (n = 8) or the original (n = 8) technique.

RESULTS

After PLC reconstruction, varus laxity was restored with no statistically significant differences from the intact condition after both reconstruction techniques. Similar outcomes were observed for external rotation in extension; however, in terms of the external rotation limit with respect to the intact joint, significant reductions of mean ± SD 4.1°± 6.3° (P = .036) and 5.1°± 6.6° (P = .016) were recorded with the modified technique at 60° and 90° of flexion, respectively. No significant effect was observed on the neutral flexion kinematics from 0° to 90° of flexion, and no significant differences were observed between reconstructions (P = .222).

CONCLUSION

Both PLC reconstruction techniques restored the normal native varus as compared with the intact knee. Although the modified technique constrained end-range external rotation at 60° and 90° of flexion, no differences were noted with neutral flexion kinematics. Care should be taken when tensioning in the modified technique so that the tibia is in a neutral position to avoid overconstraining the knee.

CLINICAL RELEVANCE

The modified technique may prove useful in situations where there are limited graft options, particularly where allografts are not available or are restricted.

ACL and Posterolateral Corner Injuries

PURPOSE OF REVIEW

The importance of the posterolateral corner (PLC) with respect to knee stability, particularly in the setting of anterior cruciate ligament (ACL) deficiency, has become more apparent in recent years. The purposes of this article are to review the current concepts of PLC injuries and to address their role in the ACL-deficient and ACL-reconstructed knee.

RECENT FINDINGS

Recent literature demonstrates that a single staged, combined reconstruction is optimal. Studies further provide more thorough insight into avoidance of tunnel collision during the multiligament reconstruction. In total, reconstruction procedures have demonstrated successful outcomes in over 90% of patients. In summary, we report that in the setting of suspected concomitant PLC and ACL injury, it is essential to address both injuries; appreciating the local anatomy, diagnostic modalities, and surgical techniques are each crucial to achieving desirable clinical outcomes.

Incidence and MRI characterization of the spectrum of posterolateral corner injuries occurring in association with ACL rupture

OBJECTIVE

To determine the incidence and MRI characteristics of the spectrum of posterolateral corner (PLC) injuries occurring in association with anterior cruciate ligament (ACL) rupture.

MATERIALS AND METHODS

We carried out a level IV, retrospective case series study. All patients clinically diagnosed with an ACL rupture between July 2015 and June 2016 who underwent MRI of the knee were included in the study. In addition to standard MRI knee reporting, emphasis was placed on identifying injury to the PLC and a description of involvement of these structures by two musculoskeletal radiologists. Association with PLC involvement was sought with concomitant injuries using correlation analysis and logistic regression.

RESULTS

One hundred sixty-two patients with MRI following ACL rupture were evaluated. Thirty-two patients (19.7%) had an injury to at least one structure of the PLC, including the inferior popliteomeniscal fascicle (n = 28), arcuate ligament (n = 20), popliteus tendon (n = 20), superior popliteomeniscal fascicle (n = 18), lateral collateral ligament (n = 8), popliteofibular ligament (n = 7), biceps tendon (n = 4), iliotibial band (n = 3), and fabellofibular ligament (n = 1). Seventy-five percent of all patients with combined ACL and PLC injuries had bone contusions involving the lateral compartment of the knee. The presence of these contusions strongly correlated with superior popliteomeniscal fascicle lesions (p < 0.05). There was no correlation between injuries to other structures of the PLC and other intra-articular lesions.

CONCLUSION

Missed injuries of the PLC lead to considerable morbidity. The relevance of this study is to highlight that these injuries occur more frequently than previously described and that an appropriate index of suspicion, clinical examination, and MRI are all required to reduce the risk of missed diagnoses. The results of this study support previous suggestions that the rate of concomitant PLC injury in the ACL-deficient knee is under-reported. The rate of combined injuries in this series was 19.7%. The key message of this paper is that PLC injury is common in the presence of ACL injury and should be sought both clinically and radiologically.