Sustainable treatment success of an Os naviculare syndrome using conservative measures, infiltration therapy, and shock waves.

Medial plantar foot pain can have various causes, and the painful Os tibiale externum should be considered in the differential diagnosis. A reliable diagnosis can be made through physical examination and multimodal imaging. We report on a 53-year-old man with severe, load-dependent pain consistent with an accessory navicular syndrome, caused by a pes planovalgus, which consecutively induced focal inflammation and tenosynovitis of the tibialis posterior tendon. Multifactorial conservative measures, including infiltration therapy, provided only moderate symptom relief. A final shockwave therapy ultimately led to a sustainable symptom relief.