Significance of sesamoid ossification in peroneus longus tendon ruptures.

Ruptures of the peroneus longus tendon are uncommon, with a small number of case reports found in published studies. The presence of an os peroneum can predispose the peroneus longus tendon to rupture at the cuboid level with or without concomitant fracture, or fracture through a partite os peroneum. Whether the os peroneum can be represented by various stages of ossification is still a matter of debate. We present 2 cases of acute peroneus longus tendon rupture at the cuboid notch in the presence of an intact os peroneum in the ossified and nonossified form. We treated patients with excision of the os peroneum and tenodesis of the peroneus longus to the peroneus brevis tendon.