Incidence of and Risk Factors for Knee Collateral Ligament Injuries With Proximal Tibia Fractures: A Study of 32,441 Patients.

Proximal tibia fractures are associated with concurrent collateral ligament injuries. Failure to recognize these injuries may lead to chronic knee instability. The purpose of this study was to identify risk factors for concurrent collateral ligament injuries with proximal tibia fractures and their association with inpatient outcomes. A total of 32,441 patients with proximal tibia fractures were identified in the 2011-2012 National Trauma Data Bank. A total of 1445 (4.5%) had collateral ligament injuries, 794 (2.4%) had injuries to both collateral ligaments, 456 (1.4%) had a medial collateral ligament injury only, and 195 (0.6%) had a lateral collateral ligament injury only. On multivariate analysis, risk factors found to be associated with collateral ligament injuries included distal femur fracture (odds ratio, 2.1), pedestrian struck by motor vehicle (odds ratio, 2.0), obesity (odds ratio, 1.6), young age (odds ratio, 1.9 for 18 to 29 years vs 40 to 49 years), motorcycle accident (odds ratio, 1.5), and Injury Severity Score of 20 or higher (odds ratio, 1.4). In addition, patients with simultaneous injuries to both collateral ligaments had higher odds of inpatient adverse events (odds ratio, 1.51) and longer hospital stay (mean, 2.27 days longer). The risk factors reported by this study can be used to identify patients with proximal tibia fractures who may warrant more careful and thorough evaluation and imaging of their knee collateral ligaments. [Orthopedics. 2018; 41(2):e268-e276.].