Traumatic dislocation of the knee.

The incidence, classification, anatomy, and biomechanical etiology of traumatic dislocation of the knee are reviewed. This injury occurs rarely, but it can result in significant long-term disability. The popliteal space must be carefully evaluated because of the high frequency of associated neurovascular injuries. If gross deformity is present, closed reduction should be performed immediately, followed by radiography to delineate possible fractures and by immobilization in a posterior splint. However, posterolateral dislocation is often irreducible by closed manipulation. The neurovascular status should be reassessed following closed reduction; liberal use of angiography is recommended. Complications from untreated vascular injury can include thrombosis. Peroneal nerve injury, less frequent than vascular damage, has a poor prognosis for long-term function recovery, and surgical repair has been of no value. Treatment of ligament injuries associated with knee dislocations has ranged from closed reduction and immobilization to open partial or total repair. Operative repair is most appropriate for young patients, active older patients, and patients with torn collateral ligaments. One study has concluded that early physical therapy, regardless of treatment, is crucial to a good outcome.