The painful accessory navicular: a clinical and histopathological study.

Twenty-two skeletally immature patients with 39 accessory tarsal navicular bones were seen over a 4-yr period. Twenty-five of the feet with accessory naviculars were symptomatic and, after failure of conservative treatment, were treated by excision of the accessory bone, the synchondrosis, and the prominent portion of the main navicular ossification process. No attempt was made to reroute the posterior tibial tendon. All 25 operative feet were completely relieved of the preoperative pain. The external oblique view was found to be the best radiographic view to demonstrate the accessory navicular. Histological findings in the surgical specimens included areas of micro-fracture through the cartilaginous synchondrosis, acute and chronic inflammation, and cellular proliferation indicative of attempted repair. These changes are consistent with the theory that chronic chondro-osseous tensile failure can occur in this condition and is responsible for the clinical findings.