Correlation analysis for the lateral condylar tibial plateau fracture and complete medial collateral ligament rupture / 中华骨科杂志

ABSTRACT

Objective:To investigate the relationship between the CT images of a lateral condylar tibial plateau fractures and complete medial collateral ligament (MCL) injury.Methods:Data of 59 patients with lateral condylar fracture of tibial plateau complicated with MCL injury admitted to Tianjin Hospital from January 2020 to November 2021 were collected, including 32 males and 27 females, aged 42.4±12.3 years (range, 19-65 years), there were 26 cases of extension injury and 33 cases of flexion injury. The patients were separated into two groups those with partial MCL injury and those with total rupture based on preoperative MR examination and intraoperative valgus stress test following fracture fixation. According to the ABC fracture classification of lateral condyle tibial plateau proposed by Sun et al., the fracture locations were determined on CT images, and the lateral plateau collapse depth (LPD) was measured. The relationship between LPD and MCL complete rupture was analyzed by receiver operating characteristic (ROC) curve.Results:Among 59 patients with lateral condylar tibial plateau fracture and MCL injury, 42 had partial injuries and 17 had complete ruptures. According to the ABC fracture classification, there were 26 cases of extension injury (involving area A), 21 cases of AB type, and 5 cases of ABC type; and 33 cases of flexion type injury, 19 cases of B type, 12 cases of BC type, and 2 cases of C type. All the 17 cases of MCL complete fracture occurred in extension injury, including type AB (14 cases) and type ABC (3 cases). The difference between the mean LPDs of the MCL full rupture group and the partial injury group was not statistically significant ( t=0.11, P=0.567), and the mean LPDs of both groups were 11.7±5.3 mm (range, 4.3-28.1 mm) and 11.5±4.8 mm (range, 3.8-23.6 mm), respectively. The area under the curve (AUC) of the ROC curve analysis was 0.504, and there was no statistical correlation between lateral platform collapse depth and MCL injury. Among the 26 patients with extensional injury area, MCL was completely ruptures in 17 cases and partially injury in 9 cases, LPD was 11.7±5.3 mm (range, 4.3-28.1 mm) and 6.6±1.8 mm (range, 3.8-9.4 mm), respectively, and the difference was statistically significant ( t=3.57, P=0.009). The best predictive cut-off value of LPD was 7.25 mm, the sensitivity was 88.2%, the specificity was 77.8%, and the AUC was 0.868. Conclusion:When the lateral condyle fracture of the tibial plateau is located in the extensional injury area (involving the A area in the ABC fracture classification) and the LPD measured on the CT image is greater than 7.25 mm, the complete rupture of the MCL should be considered. Clinical MCL repair is required after the fracture fixation surgery for improved surgical outcomes.