Summary

Secondary stabilizers, particularly the menisci, may sustain injuries over time if residual rotational instability persists following ACL reconstruction. In cases where a bucket handle meniscus tear is present in an ACL-reconstructed knee, it is crucial to address this with a supplemental anterolateral corner augmentation procedure to prevent the risk of re-injury.

Abstract

Introduction

Anatomical anterior cruciate ligament (ACL) reconstruction improves knee stability and typically yields excellent outcomes. However, meniscal tears remain a common cause for reoperation, even when the neo-ligament is intact.
Rotational control of the knee is primarily achieved through the reconstructed ACL (rACL), but secondary stabilizers, such as the menisci, may become injured over time if this is inadequate. Residual rotational instability following ACL injury can be attributed to additional anterolateral soft tissue damage, particularly to the iliotibial band and the anterolateral ligament (ALL).
Risk factors include young age, female sex, post-reconstruction knee laxity, and participation in pivoting sports. Consistent with presented patients. Additionally, females have been shown to have a higher risk of rACL failure.
Case presentation: We present two cases of female athletes who underwent rACL at 17 years old. One receiving a semitendinosus-gracilis autograft (Patient 1), and the other an allograft (Patient 2). Patient 1 is a competitive soccer player, while Patient 2 practices recreational skiing. Four years post-surgery, both patients experienced knee joint blockage after sports activities involving pivoting movements.
On examination, both patients exhibited unilateral joint effusion, joint line tenderness, and functional impairment, with their knees in a semi-flexed position and pain during weight-bearing. Due to pain, knee stability could not be assessed at the emergency room.
Magnetic resonance imaging (MRI) revealed intact neo-ACLs in both patients. However, Patient 1 had a bucket-handle tear of medial meniscus, while Patient 2 had a similar tear of the lateral meniscus.
Both patients were diagnosed with bucket-handle meniscal tears (BHMT) in previously ACL-reconstructed knees. There was also a suspicion of residual anterior and rotational instability of the ACL.
Both patients underwent surgery. Intraoperative evaluation under anesthesia revealed residual anteroposterior instability and significant pivot shift. Arthroscopy confirmed lax, but continuous, neo-ACLs. The meniscal tears were reduced and sutured using inside-out and all-inside techniques. Additionally, an anterolateral corner (ALC) augmentation procedure was performed using the Antwerp Monoloop technique (anterolateral tenodesis with the iliotibial band).
Both patients had favorable outcomes with no wound or knee functionality complications. After completing rehabilitation with physiotherapy, they were cleared for competitive sports at five months post-surgery. Currently, three years post-operation, neither patient has experienced further injuries.

Discussion

ALC augmentation procedure alongside rACL have shown promise in controlling rotational instability and pivot shift, making this a viable option for revision surgeries, patients with hyperlaxity, high-grade pivot shifts, or those involved in high-demand pivot sports. Studies by Lagae et al. demonstrated that the Antwerp Monoloop technique effectively restored native tibial anterior translation and internal rotational laxity compared to isolated rACL.
In the presented cases, young female, the absence ALC augmentation procedure, combined with the use of allograft in one case, likely contributed to greater rotational instability, predisposing the patients to meniscal injuries. We propose that ALL tenodesis could correct excessive rotational laxity and anteroposterior laxity, protecting the meniscal repair and potentially preventing rACL revision surgery.

Conclusion

We recommend considering extra-articular stabilization for patients with risk factors for rACL failure who present with isolated BHMT.