Summary

ACL avulsion due to tibial eminence fracture may lead to anterolateral knee instability. Early surgical management with an arthroscopic three-point suture technique via transosseous tunnels, combined with meniscus repair is effective. This method provides an adequate fixation supporting multidirectional forces and ensures favorable results and a successful return to sport.

Abstract

Introduction

Anterior cruciate ligament (ACL) avulsion due to tibial eminence fracture is an uncommon injury, with an approximate incidence of 3 for every 100,000 people a year, which represents between 1% and 5% of all ACL injuries in adults. According to the Meyers & McKeever modified classification, surgical management is indicated on type 2 injuries, with a displacement greater than 2mm, as well as on type 3 and 4. Early treatment has excellent outcomes, but management could be more difficult in cases that evolve to nonunion and displacement, even without instability.
Case presentation
A 23 year old patient suffered a left knee valgus twist injury with a fixed foot playing soccer, which resulted in immediate functional impairment. That day, he was diagnosed with an ACL avulsion due to a tibial fracture, associated with a bucket-handle lateral meniscus tear. The treatment included an arthroscopic reinsertion of the ligament by a three high-strength (6-strand) suture point with transosseous tunnels, alongside the repair of the meniscus. The patient continued with a typical ACL rehabilitation protocol, returning to physical activity (including pivoting sports) in 10 months and with a normal magnetic resonance (MRI) 1 year postoperative.

Discussion

ACL avulsion following tibial eminence fracture is uncommon. Frequently affecting children and adolescents because the physis is weak compared to the ligament. However, it can occur in adults, causing anterolateral knee instability. Its incidence has increased, partly due to the rise of physical activity in infants and high energy trauma in adults.
The management of these injuries is based on the severity of the displacement, according to Meyers & McKeever modified classification. Recently, Green et al. proposed a new classification based on MRI findings, which is equally trustable and gives quantitative guidelines for treatment. Surgical techniques have evolved, with arthroscopic methods reducing the open arthrotomy approach. Many fixation techniques have been described, including Kirschner wires, screws, sutures or suture anchors. Comparisons between screws and sutures have not demonstrated significant differences regarding range of movement (ROM) loss, arthrofibrosis or laxity on pivot shift test, which indicates that there is not a clear preference between methods.
The ACL reinsertion can be done through arthroscopic techniques using three suture points with hybrid intra articular sutures and external tension bands via transosseous tunnels. This technique provides adequate compression, fixation and reduction, supporting multidirectional forces. Results have shown to be favorable, with significant improvement on Lysholm and IKDC scores and Tegner activity level. Common complications include ROM loss, malunion, impingement and residual laxity, being the physis injuries of greatest concern in growing bones.

Conclusion

In this case, the ACL repair with three suture point fixation and meniscus tear correction resulted in an excellent joint function and successful return to sport. This technique, minimally invasive and with low perioperative complication rates, is reproducible and suggested as a valid option in the management of similar injuries.