[Tendon transfers in postoperative hallux varus. Apropos of 12 cases]

Iatrogenic hallux varus deformity after bunion surgery is a post-operative condition in which the great toe is oriented in medial deviation in relation to the first metatarsal head. This overcorrection can be a disabling complication with poor cosmetic appearance. A review of the surgical literature showed a reported hallux varus incidence range of 2 p. 100 to 13 p. 100. Various surgical interventions to treat hallux varus are described in the literature and we present here our experience in operative management of acquired hallux varus based on the results of surgical repair with the Johnson (extensor hallucis longus tendon) EHLT transfer procedure and the Hawkins (abductor hallucis tendon) procedure in 12 patients.

All of the patients suffered from painful iatrogenic hallux varus and conservative treatment was unsuccessful in all cases. The mean duration of follow-up was 42 months (range 8-96). The average age was 37 years (range: 17 to 58). The index procedure in eleven patients was a Mc Bride bunionectomy and in one case a Petersen procedure. On physical examination, a claw deformity of the hallux characterized by extension of the metatarsophalangeal joint and flexion of the interphalangeal joint was noted in all feet. Eight transfers of the abductor hallucis tendon and four complete transfers of the extensor hallucis longus tendon with interphalangeal joint fusion were done. At the time of the final follow-up, patients were interviewed and graded using a standardized questionnaire based on pain, metatarso-phalangeal range of motion, alignment of the hallux, footwear requirements, walking capabilities and first ray rest.

Eleven patients reported satisfactory results and one patient a fair result. Overcorrection was a potential complication and in this retrospective study, one bunion deformity recurred but was asymptomatic. On radiographic evaluation the hallux abductus angle was improved by a mean 26.6 degrees and the average first intermetatarsal angle was 7 degrees (range: 3 degrees to 12 degrees ). A narrowing of the metatarso-phalangeal joint was observed in four cases (2 Johnson and 2 Hawkins).

The addition of a tendon transfer to the medial soft tissue release is recommanded in most cases of hallux varus in active patients without osteoarthritis of the metatarso-phalangeal joint. Our experience with the EHLT transfer or the abductor hallucis tendon transfer demonstrated excellent correction of the hallux varus deformity; however metatarso-phalangeal joint stiffness was frequently observed. As originally described by Johnson et Spiegl, the entire extensor hallucis longus tendon was used in conjunction with an interphalangeal joint arthrodesis in the presence of a fixed and painful deformity of the hallux interphalangeal joint. If no fixed claw deformity was present an abductor hallucis tendon transfer was preferred. Onset of degenerative disease involving the metatarso-phalangeal joint in four cases may jeopardize long term survival of these surgical results.