Background Knee dislocation is a serious injury, representing less than 0.2% of all orthopedic injuries, and 16% to 40% of these patients suffer an associated injury to the common peroneal nerve (CPN). However, it is still unclear which structures are most intently associated with CPN injury. This study attempts to analyze the potential risk factors for CPN injury and provide clues for a comprehensive diagnosis of knee dislocation. Methods We retrospectively reviewed 153 cases of knee dislocation related to lateral and/or posterior ligament injury between 2015 and 2018. All 153 patients were divided into the CPN injury group or the no-CPN injury group. The baseline characteristics included age, gender, cause of injury, posterior cruciate ligament (PCL) disruption, anterior cruciate ligament (ACL) disruption, popliteofibular ligament and/or tendon of popliteus injury, biceps femoris tendon injury and fibular head fracture. We identified potential variables for a multivariable logistic regression model to identify the major risk factors for CPN injury. Results Multivariate regression analysis revealed the biceps femoris tendon injury and fibular head fracture to be predictive of CPN injury in knee dislocation. Gender, age, cause of injury, ligamentous classification, popliteofibular ligament and/or tendon of popliteus injury, PCL disruption or ACL disruption do not predict CPN injury. Conclusions Biceps femoris tendon injury and fibular head fracture are risk factors of CPN injury in knee dislocation. A better understanding of the risk factors for CPN injury allows surgeons to achieve more accurate diagnoses.