The Adductor Hallucis Revisited

Abstract

To evaluate anatomic variability in the insertion of the adductor hallucis into the lateral sesamoid and proximal phalanx of the great toe and to evaluate the extent of release of the adductor hallucis tendon performed through an incision in the dorsal first-web space, we recorded the angle of hallux valgus in 42 fresh-frozen specimens from human cadavers. An incision was made for a realignment of the soft tissues, dissecting down to the level of the intermetatarsal ligament. A loop of suture was placed around the identifiable adductor hallucis tendon through this incision along the lateral aspect of the lateral sesamoid. Then a plantar dissection removed all soft tissue to the level of the intermetatarsal ligament, adductor hallucis (transverse and oblique heads), lateral sesamoid, and lateral flexor hallucis brevis. The insertion of these muscles into the proximal phalanx was evaluated. Specifically, we looked for separate slips of the adductor tendon inserting into the base of the proximal phalanx or separate insertions of the adductor tendon and the tendon of the flexor hallucis brevis muscle. In 33 of the 42 specimens, the entire adductor hallucis tendon had been isolated by the loop of suture through the incision in the dorsal first web. In eight of the remaining nine specimens, a small slip of the tendon (comprising less than 25% of its substance) had not been included. No specimen was found to have a separate slip of the adductor tendon inserting into the base of the proximal phalanx. Instead, all specimens were found to have only a conjoined insertion of fibers of the adductor hallucis and of the flexor hallucis brevis from the lateral sesamoid into the base of the proximal phalanx. We did not identify a separate tendon-insertion into the proximal phalanx in any specimen. Therefore, great caution should be exercised in releasing an isolated insertion of the adductor tendon from the base of the proximal phalanx of the great toe since it may actually represent the conjoined insertion of the lateral flexor hallucis brevis tendon and the adductor tendon. We found that by simply releasing the adductor tendon from its insertion along the lateral aspect of the sesamoid, accomplished through an incision in the dorsal first web, that an adequate release was achieved in most specimens.