Fracture of the accessory navicular

Imaging of tarsal navicular disorders: a pictorial review

The tarsal navicular is a bone within the midfoot that plays a critical role in maintaining the arch of the foot. This bone is clinically relevant because it may be affected by a wide array of pathologies. Our approach includes a detailed description of the imaging characteristics and disorders affecting the tarsal navicular. Organization includes (a) normal imaging, (b) accessory ossicles, (c) coalition, (d) fractures, (e) Kohler's disease, (f) osteonecrosis, (g) osteochondral lesions, (h) arthropathies, and (i) tumors. The purpose of this article is to discuss normal variants and pathological processes that can affect the tarsal navicular, with emphasis on the often-overlooked imaging findings.

Prevalence of accessory ossicles and sesamoid bones in hallux valgus

BACKGROUND

Sesamoid bones and accessory ossicles of the foot and ankle, although mostly asymptomatic, can be sources of pain or degenerative changes in response to overuse and trauma. We investigated the prevalence of accessory ossicles and sesamoid bones in a population of Italian women with hallux valgus.

METHODS

A single-center study was performed to determine the prevalence of accessory ossicles and sesamoid bones in the ankle and foot. A total of 505 women with hallux valgus aged 26 to 80 years at the time of hallux valgus correction were examined. Anteroposterior, oblique, lateral foot radiographs and a Muller view were examined regarding the presence, prevalence, coexistence, and distribution of accessory ossicles and sesamoid bones in both feet. The radiographs were analyzed independently by three experienced specialists in foot and ankle surgery. Disagreements were discussed in a consensus meeting, where the radiographs were reevaluated and a final decision was made.

RESULTS

There was no statistically significant difference between data of the accessory ossicles and sesamoid bones according to the χ(2) test. Sesamoid bones were detected in 404 of the 505 patients. The fifth metatarsal sesamoid bone was found in 97 patients. All of the patients presented hallucal sesamoid bones.

CONCLUSIONS

This is the first detailed report of the prevalence of accessory ossicles and sesamoid bones of the feet in Italian women with hallux valgus. These findings could help clinicians in the diagnosis and management of disorders of accessory ossicles and sesamoid bones, which are often undiagnosed, painful foot syndromes.