Preoperative CT-measured lateral widening is an independent associated factor with CT-detected cruciate ligament avulsion in tibial plateau fractures

OBJECTIVE: To identify radiographic and computed tomography (CT) parameters predictive of cruciate ligament avulsion fractures in patients with tibial plateau fractures (TPFs). METHODS: We retrospectively analyzed 127 patients with TPFs, categorized by the presence (n = 39) or absence (n = 88) of cruciate ligament avulsion fractures. Demographic variables, fracture classification, and radiographic parameters measured on plain radiographs and CT images were compared using univariate analysis. Multivariate logistic regression and Receiver Operating Characteristic (ROC) analysis were performed to identify independent associated factors and diagnostic thresholds. RESULTS: Cruciate ligament avulsion fractures occurred in 30.7% of patients and were most frequently associated with high-energy Schatzker type V and VI fractures. On univariate analysis, both CT-measured lateral plateau widening (10.6 ± 5.6 mm vs 7.5 ± 4.6 mm, P = 0.003) and radiographic lateral widening (10.8 ± 6.1 mm vs 9.0 ± 11.0 mm, P = 0.011) were significantly greater in the avulsion group. Multivariate logistic regression identified CT lateral widening as the only independent -associated factor for cruciate ligament avulsion. ROC analysis demonstrated moderate discriminative ability for CT lateral widening (area under the curve = 0.655), with an optimal cutoff value of 6.8 mm yielding a sensitivity of 79.5%. CONCLUSIONS: CT-measured lateral plateau widening is an independent preoperative indicator of cruciate ligament avulsion in tibial plateau fractures. A lateral widening threshold of approximately 6.8 mm on CT should be regarded as a quantitative imaging "secondary sign" prompting heightened suspicion for associated ligamentous avulsion injury and consideration of comprehensive preoperative planning. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.