Displaced Fifth Metatarsal Base Fracture With Retraction of Peroneal Brevis Tendon Treated With Allograft Reconstruction

Base of the 5th metatarsal (MT) fracture is a common occurrence that needs to be identified and treated appropriately to minimize risk of poor clinical outcomes. An uncommon occurrence is the base of 5th MT fractures associated with progressive retraction of the peroneal brevis (PB) tendon resulting in foot eversion weakness. We report a case of 5th MT base avulsion fracture with sequential proximal retraction of the displaced fragment with its attached PB tendon. A middle-aged gentleman was referred to our clinic after sustaining a foot inversion injury with localized tenderness at the base of 5th MT associated with swelling on ambulation and weakness on eversion. Radiographs exhibited an avulsion fracture at the base of 5th MT with proximal retraction. He was counselled and underwent surgical reconstruction of the avulsed PB tendon with a posterior tibial tendon (PTT) allograft. At 3-month follow-up, there was progressive return of foot eversion strength. By 6 months, the patient returned to functional ambulation and light jogging. Our case utilizing a PTT allograft for reconstruction of a contracted peroneus brevis and displaced 5th metatarsal avulsion fracture suggests a viable treatment option showing good clinical and functional outcomes. Level of Evidence: Level V.