Table 1 Prevalence, clinical significance, and differential diagnosis of the most common types of variants and accessory ossicles in the midfoot
Ossicle | Prevalence | Clinical significance | Differential diagnosis | |||
|---|---|---|---|---|---|---|
Accessory navicular | 4–21% | I | ~ 30% | Asymptomatic | – | |
II | 50% bilateral 50–90% | Disruption of the synchondrosis Chronic tendinosis or tear Flat-foot deformity Osteonecrosis | Avulsion fractures of the tuberosity | |||
III | ~ 30% | Irritation of the surrounding tissues Adventitial bursa formation Flat foot deformity | – | |||
Os supranaviculare | 1% | Asymptomatic | Avulsion fractures of the capsule of the talonavicular joint | |||
Os peroneum | 3–26% (ossified form) multipartite – 30% bilateral – 60% | Painful os peroneum syndrome Peroneus longus tear | Fracture (os trigonum—os subfibulare if migrated, multipartite if not) | |||
Rare | Bipartite medial cuneiform | 0.3–2.4% | Degeneration and overuse syndromes | Fracture | ||
Os cuboideum secundarium | – | Asymptomatic | Potential to mimic a mass on MR | |||
Os intercuneiforme | 0.026% | Asymptomatic | Fracture | |||