Dislocation of the proximal fibula

Increased fibular external rotation, due to distortion of the ankle, will result in injury to the anterior capsule and ligaments of the proximal tibiofibular joint causing common complaints of ëpoppingí and lateral knee pain. The problems arise from a dislocation, instability or blocking of the joint. Recurrent dislocations of the superior tibiofibular joint are rare. The majority of the patients are physically active, young adults. A bad landing during a hurdles race may cause the injury. Complains are sometimes associated with neurological symptoms due to compression or provocation of the common peroneal nerve, i.e. foot drop.

Anatomy

The proximal tibiafibular joint is an arthrodial joint composed of the tibial facet located on the posterolateral aspect of the rim of the tibial condyle and the fibular facet on the medial upper surface of the head of the fibula. A fibrous capsule surrounds the articulation with two prominent ligaments. The synovial membrane lines the articulation and, in some instances, is continuous with the popliteus bursa, which communicates with the knee joint.

Diagnosis
The symptoms of locking, pain en giving way may lead to an erroneous diagnosis of meniscal injury. But there is no significant effusion and there are no signs of internal knee derangement or instability.
The protrusion of the head of the fibula can be noticed during comparative examination of both knees, and mainly while making a front, profile and postero-internal oblique comparative X-ray.
Instability or blockage can also be noticed by comparative examination, especially making a anterior-posterior translation of the head of the fibula. If instability is present, with palpation or translation neurological symptoms sometimes can be provoked.

Treatment
Recent cases of dislocation necessitate a reduction, followed or not by strapping. In old cases of instability modifications of patients activity level and training programs will be needed, as utilization of a supportive strap, lower leg strengthening, and modifications in the lower kinetic chain biomechanics. Blocking of the joint often can be resolved by a mobilization maneuver, pushing the knee in deep flexion while holding ones wrist in the back of the knee.
Different surgical techniques have been described for the management of this pathology, meaning resection, artrodesis or reconstruction.
Spontaneous resolution of the nerve injury will occur in two months with no residual joint instability.

References
Semonian, RH. Denlinger PM. Duggan RJ. Proximal tibiofibular subluxation relationship to lateral knee pain. JOSPT 21 (5) 1995, 248-257.
Turco, VJ. Spinella AL. Anterolateral dislocation of the head of the fibual in sports. American J Sports Med 13 (4) 1995, 209-215.