Summary A proximal tib-fib dislocation is a disruption of the proximal tibia-fibula joint associated with high energy open fractures of the tibia and peroneal nerve injury. Diagnosis requires careful assessment of radiographs of the knee and tibia (often missed injury). Treatment is prompt closed reduction with unstable injuries requiring surgical pinning versus soft tissue reconstruction. Epidemiology Incidence rare injury even less common as an isolated injury Demographics most common in 2nd to 4th decades Etiology Pathophysiology mechanism high-energy trauma more common with horseback riding and parachuting fall onto a flexed and adducted knee Associated conditions posterior hip dislocation (flexed knee and hip) open tibia-fibula fractures other fractures about the knee and ankle Anatomy Arthrology proximal fibula articulates with a facet of the lateral cortex of the tibia distinct from the articulation of the knee joint is strengthened by anterior and posterior ligaments of the fibular head Nerves common peroneal nerve lies distal to the proximal tibiofibular joint on the posterolateral aspect of the fibular neck Classification Ogden classification subluxation and 3 types of dislocation anterolateral - most common posteromedial superior Presentation Symptoms lateral knee pain symptoms can mimic a lateral meniscal tear instability Physical exam tenderness about the fibular head comparison of bilateral knees with palpation of normal anatomic landmarks and their relative positions can clarify the diagnosis Imaging Radiographs recommended views AP and lateral of both knees comparison views of the contralateral knee are essential CT scan clearly identifies the presence or absence of dislocation Treatment Nonoperative closed reduction indications acute dislocations technique flex knee 80°-110° and apply pressure over the fibular head opposite to the direction of dislocation post-reduction immobilization in extension vs. early range of motion (controversial) outcomes commonly successful with minimal disadvantages Operative surgical soft tissue stabilization vs. open reduction and pinning vs. arthrodesis vs. fibular head resection indications chronic dislocation with chronic pain and symptomatic instability Complications Recurrence Common peroneal nerve injury usually seen with posterior dislocations Arthritis rarely occurs and is usually minimally symptomatic