Frequency and characteristics of extensor hallucis capsularis: A cadaveric study

Abstract

© 2016, Medical Association of Thailand. All rights reserved. Background: Extensor hallucis capsularis is an accessory extensor tendon that is sporadically observed at the medial side of the extensor hallucis longus tendon. Knowledge regarding frequency of occurrence and size of the tendon may help surgeons decide whether to use this tendon or not when tendon graft is needed during foot surgery. Objective: To evaluate the frequency, size, origin, and insertion of the extensor hallucis capsularis tendon in cadaveric study subjects. Material and Method: Extensor hallucis capsularis tendon was examined via dissection of 55 cadaveric feet. Thirty-six male and 19 female cadavers were included, with an age range of 33 to 90 years (mean 67.3±14.0). One foot from each study subject was dissected and evaluated (29 left feet and 26 right feet). Demographic data (gender, age, and height) and outcome data (frequency, origin, insertion, length, and width of the tendon) were recorded. Tendon measurement reliability was evaluated by intraclass correlation coefficient. Results: Extensor hallucis capsularis tendon was found in 90.9% of cadaveric subjects. Mean tendon length and width was 11.3±4.0 cm and 1.6±0.6 mm, respectively. Most tendons branched from the extensor hallucis longus tendon and attached to the first metatarsophalangeal joint capsule. Conclusion: Extensor hallucis capsularis tendon was found in the vast majority of cadavers evaluated in this study. Most originated from the extensor hallucis longus tendon and inserted into the first metatarsophalangeal joint capsule. Application of this tendon as a tendon graft should be carefully considered due to variations of the length and the narrow width which may limited strength of this tendon graft.