THE GROSS ANATOMY OF THE INTERPHALANGEAL JOINT OF THE GREAT TOE: IMPLICATIONS FOR EXCISION OF PLANTAR CAPSULAR ACCESSORY OSSICLES

Abstract

Background Bony or cartilaginous ossicles appear at the plantar aspect of the interphalangeal joint of the great toe. The variation in pattern, prevalence and anatomic relationships of these structures is not clearly established in the literature, especially in a Caucasian population. Without this knowledge, pathology at this joint may be underestimated and surgical approaches may be poorly planned particularly as radiographs underestimate the incidence of ossicles at this joint. The aims of this study were to determine the incidence and pattern of ossicles at this joint and to establish their anatomical relationships in order to aid planning the approach for their excision.

Method The left great toe interphalangeal joint was dissected in forty British Caucasian cadavers and the pattern of ossicles and their anatomic relationships were established.

Results In 27.5% of specimens, there was no identifiable ossicle and in these cases, the tendon of flexor hallucis longus was adherent to the joint capsule. In the remaining specimens (72.5%), a bursa separated the tendon of flexor hallucis longus from the plantar joint capsule and ossicles were found embedded within the joint capsule. Over a half (52.5%) of the specimens had a single ossicle located centrally within the plantar capsule and the remaining 20% had two ossicles lying within the capsule.

Conclusion This study shows that a large proportion of the population have either one or two bony or cartilaginous ossicles at this joint. In addition, the study has clarified the anatomy of this joint and shown that, when present, ossicles do not lie within the tendon of flexor hallucis longus and could be most safely approached from either a medial or lateral approach.