Initial Evaluation and Classification of Knee Dislocations

The traumatic knee dislocation (KD) is a complex condition resulting in injury to >1 ligament or ligament complexes about the knee, termed multiligament knee injuries. Typically, KDs result in injury to both cruciate ligaments with variable injury to collateral ligament complexes. Very rarely, KD may occur with single cruciate injuries combined with collateral involvement but it is important to understand that not all multiligament knee injuries are KDs. Patients can present in a wide spectrum of severity; from frank dislocation of the tibiofemoral joint to a spontaneously reduced KD, either with or without neurovascular injury. The initial evaluation of these injuries should include a thorough patient history and physical examination, with particularly close attention to vascular status which has the most immediate treatment implications. Multiple classification systems have been developed for KDs, with the anatomic classification having the most practical application.