Unusual proximal fragment migration of an os peroneum fracture with associated peroneus longus tendon injury-a tree often hides a forest.

We report the case of a 55-year-old male patient who presented to the emergency department after sustaining a right ankle trauma. Swelling and tenderness of the lateral aspect of the right ankle were present on physical examination without evidence of motor or sensory deficit. Ankle radiographs were performed and showed two bony fragments, the first located postero-inferiorly to the cuboid bone while the second was adjacent to the tip of the lateral malleolus. The diagnosis of an os peroneum fracture was made with high suspicion of an associated peroneus longus tendon rupture. Computed tomography (CT) and magnetic resonance imaging (MRI) of the right ankle confirmed the diagnosis of a subtotal retracted tendinous rupture. Successful surgical repair of the injured tendon was performed. This article illustrates the imaging findings of an os peroneum fracture with its associated tendinous injury and reviews the literature.