Chronic Peroneal Tendon Subluxation-Dislocation

Physical Examination

• When the ankle joint is passively circumducted, subluxation may be identified as a palpable “click” over the lateral malleolus. Resistance to active dorsiflexion and eversion of the foot may induce pain posterior to the fibula, and subluxation or dislocation of the peroneal tendon can occur.

• With active circumduction of the foot, a subtle side-to-side difference of peroneal tendon excursion may be palpated.

• An inability to dislocate the tendons does not rule out instability. Coexisting ankle instability and peroneal tendinopathy should be identified.

• Imaging helps to evaluate concomitant injuries and to confirm the diagnosis.

• Plain radiographs should be taken in anteroposterior, lateral, and mortise views.

  • Often a normal, small flake of fibular cortex is pathognomonic for peroneal dislocation ( Fig. 69.1 ).

    

  • Ankle stress views can be taken to evaluate concomitant ankle instability.

• Magnetic resonance imaging (MRI) is useful for assessment of the posterior fibular groove, and concomitant ligament and peroneal tendinopathy. Fig. 69.2 shows insufficiency of the posterior fibular groove and the superior peroneal retinaculum on MRI.

  

• Computed tomography (in uncertain cases) may be helpful to evaluate the posterior fibular groove.