Tx and Followup:
Conservative management is the first line of treatment. Those who do not respond to conservative management may benefit from surgery with anastomosis of the fragments or tenodesis to the peroneus longus tendon.
This peroneus brevis tendon split tear has one muscle belly from which a single tendon arises with a vertical tear. One would expect two separate muscle bellies surrounding each of the tendon slips if a bifurcate brevis tendon were present. A small accessory peroneus quartus muscle was present in this case; however, its tendon was separate from the longitudinal tear in the peroneus brevis tendon. Sometimes the tendon of the peroneus quartus muscle can be mistaken for a split peroneus brevis muscle.
Kaplan PA, et al. Musculoskeletal MRI. Philadelphia, PA: W.B. Saunders Company. 2001: 401-403.