Posterolateral tibial plateau fractures are associated with anterolateral complex injuries of the knee in primary ACL injury

PURPOSE: Posterolateral tibial plateau fractures (PLTFs) have been increasingly studied due to their association with soft tissue injuries around the knee. This prospective study aimed to determine whether the presence of PLTFs is associated with soft tissue injuries around the knee and correlates with an increased preoperative quantitative pivot shift (PS). It was hypothesized that the presence of PLTFs is associated with greater clinical and quantitative PS. METHODS: A prospective registry study was conducted, and patients who underwent primary unilateral anterior cruciate ligament (ACL) reconstruction at a single institution were included. The PS test was preoperatively performed in general anaesthesia and quantified using the PIVOT iPad application. The anterior translation of the lateral tibia plateau (ATLT) was measured in both the injured and uninjured knee, and the side-to-side difference was calculated. The PS test was additionally graded according to International Knee Documentation Committee (IKDC) criteria. PLTFs were classified according to Bernholt's classification. Injuries to the Kaplan fibres (KFs), anterolateral complex (ALC) and the menisci were evaluated on preoperative magnetic resonance imaging (MRI) scans. Student's t-test was used to compare means, and chi-square was used to test for correlations. Statistical significance was set to p < 0.05. RESULTS: A total of 142 patients with a mean age of 30.9 ± 11.7 years were included. PLTFs were present in 94 (66%) of patients. The presence of PLTFs was associated with concomitant injuries to the KF (p < 0.001), ALC (p < 0.001), medial and lateral meniscus (both p < 0.01). The presence or the severity of a PLTF did not increase the ATLT during quantitative PS or IKDC PS grading (n.s.). CONCLUSION: PLTFs are associated with concomitant injuries to the ALC and both menisci, indicating that they occur within a broader pattern of structural knee damage. However, these injuries do not appear to contribute to a greater preoperative PS. The presence of PLTFs should alert surgeons to the high probability of associated injuries. LEVEL OF EVIDENCE: Level III, diagnostic studies.