Flexor Hallucis Longus Loose Bodies- An Unusual Cause of Plantar Midfoot Pain

Midfoot pain is a common complaint but occurs less frequently in the plantar aspect. A myriad of causes have been reported including trauma, plantar fasciitis, Flexor hallucis longus (FHL) or posterior tibial tenosynovitis, midfoot osteoarthritis and stress fractures especially during weight-bearing. The FHL tendon sheath has been shown to communicate with the ankle joint. Osseous bodies can be seen within tendon sheaths especially in synovial chondromatosis. We report a rare case of loose bodies, not secondary to an underlying inflammatory or synovial condition but from the ankle traversing into the FHL tendon sheath, causing pain during weight bearing. We believe this to be the first reported case in English literature.