Arthroscopically assisted refixation of bony ACL tears with accompanying posteraleral tibial plateau (“apple bite”) fractures – a minimally invasive treatment approach

PURPOSE: Combined fractures involving bony avulsion of the anterior cruciate ligament (ACL) with a concomitant impression fracture of the posterolateral tibial plateau are rare injuries, with limited data available in the literature. Therefore, the aim of this study was to evaluate the functional and clinical outcomes of arthroscopically assisted treatment for these osteoligamentous injuries. METHODS: We retrospectively reviewed 16 patients after a mean follow-up of 24.3 ± 10.6 months (12–45 months) who underwent arthroscopically assisted treatment for these named injuries. The fixation of the ACL avulsion was carried out either with two crossed, cannulated 2.7 mm screws or using transosseous sutures (12 and 4 patients, respectively). The reduction and fixation of the tibial plateau fracture with an articular step-off greater than 2 mm was performed arthroscopically assisted by screw osteosyntheses (9 patients). Primary outcome parameters were the Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS), Numeric Rating Scale (NRS) Pain Score, and International Knee Documentation Committee (IKDC) score. Secondary outcome parameters included bony consolidation, complications, and surgical revisions. RESULTS: The mean Lysholm score, KOOS and IKDC score were 84 ± 13, 81 ± 14%, and 78 ± 11, respectively. The NRS score had a median of 1.6, the median Tegner activity score was 4.5. Complete bony healing was achieved in all patients. Neither perioperative complications nor surgical revisions occurred. During follow-up, 6 patients showed persistent 1° laxity of the ACL in a side-to-side comparison without rotational instability. Two patients had a 5° extension deficit on the affected side. CONCLUSION: Arthroscopically assisted fixation of combined bony ACL tears and posterolateral tibial plateau fractures as a minimally invasive procedure results in good functional outcomes with sufficient joint stability. It offers the advantage of useful visualization of the joint surface, which helps to avoid residual intraarticular step-offs and posterolateral malalignment. ACL avulsion fixation is possible both through crossed screw osteosynthesis and transosseous sutures techniques in an arthroscopic setting.