Epidemiology and Imaging Appearance of the Normal Bi-/multipartite Hallux Sesamoid Bone

Background: Turf toe is a hyperextension injury of the hallux metatarsophalangeal joint that can be difficult to diagnose on physical examination and imaging. Diastasis of the bi- or multipartite sesamoid of the hallux has been implicated as 1 potential radiographic finding of turf toe injury, and when present may require operative management. However, the normal interval for the bi-/multipartite sesamoid has not yet been established. Methods: A total of 671 foot radiograph series were reviewed in effort to quantify the dominant interval of the bi-/multipartite sesamoid bone with respect to potential influencing factors including right versus left foot, medial and/or lateral sesamoid involvement, patient age and gender, and weight versus non-weight-bearing radiograph technique. Results: The prevalence of a bi-/multipartite hallux sesamoid was 14.3% in our population. The dominant sesamoid interval ranged from 0-2 mm, with an average of 0.79 mm. Conclusion: We conclude that sesamoid diastasis should be considered, in the appropriate clinical setting, when the sesamoid interval is greater than 2 mm on a routine AP radiograph of the foot. Level of Evidence: Level III, comparative study.