The Fibular Fleck Sign: An Avulsion Fracture of the Superior Peroneal Retinaculum

Abstract

Background:
The peroneus longus and brevis tendons course through the posterior fibular groove and are stabilized by the superior peroneal retinaculum (SPR). Avulsion fractures of the SPR, radiographically identified as the “fibular fleck sign,” are uncommon but clinically significant injuries associated with peroneal tendon instability.

Case Presentation:

We report the case of a 22-year-old male who presented with right ankle pain and swelling following a fall. Radiographs demonstrated a small bony fragment lateral to the distal fibula consistent with an avulsion fracture of the SPR (fibular fleck sign). Surgical exploration revealed anterior dislocation of the peroneal tendons without tendon rupture. The bony fragment was reduced and stabilized using a suture anchor and K-wire fixation. Postoperative rehabilitation included immobilization followed by gradual weight-bearing and physical therapy. At the three-month follow-up, the patient was asymptomatic with no evidence of tendon instability.

Conclusion:
The fibular fleck sign is a rare but important radiographic indicator of SPR avulsion and peroneal tendon dislocation. Early recognition and appropriate surgical management are essential to prevent chronic instability and functional impairment.