Partite hallux sesamoid bones: Relationship with sesamoid bones at other metatarsophalangeal joints

Introduction - Partite hallux sesamoids are clinically meaningful but their association with other sesamoids is not clear. The objective was to relate the prevalence of the partite hallux sesamoid bones to sesamoid bones at other metatarsophalangeal (MTP) joints. Methods - We conducted a retrospective review of plain radiographs of 7946 adult feet between November 2005 and September 2012 in order to identify partite hallux sesamoids and sesamoids at other MTP joints. Coexistence patterns of the partition and extra sesamoids were studied. Presence or absence of sesamoids at other MTP joints as well as sex and laterality were compared between the feet with and without partite hallux sesamoids using Pearson Chi-square test. Association between age and partition was evaluated using Spearman's correlation coefficient. Results - Overall partite prevalence rate is 6.82%, and coexistence with extra MTP sesamoids was 0.42%. One pattern was partition in hallux sesamoid only, and 4 patterns were coexistence with extra sesamoids. The prevalence rates of partite hallux sesamoids were 7.17% (508/7081) and 3.93% (34/865) in feet without and with extra sesamoids, respectively. The relative risk of 1.889 (95% CI, 1.325-2.693) of partite hallux sesamoids was noted in feet without than with extra sesamoids (Χ2 =12.759, P <0.001). A negative correlation between age and distribution of partition was identified (r=-0.061, P <0.001). Conclusions - Partition of hallux sesamoid bones is a developmental variation, it can coexist with sesamoids at other MTP joints following a certain pattern; and its prevalence rate is almost twice higher in feet without than with extra MTP sesamoids. This article is protected by copyright. All rights reserved.