Flexor hallucis longus tendon transfer: evaluation of postoperative morbidity

Clinical and pedobarograph evaluation was performed on 16 patients following flexor hallucis longus (FHL) tendon transfers to determine the resulting morbidity due to the loss of FHL function. All patients underwent FHL tendon transfer for either chronic tendon Achilles rupture or chronic Achilles tendinosis. Clinical evaluation of hallux function was performed using the American Orthopaedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal scale, the SF-36 score, and a clinical questionnaire to assess alteration in the clinical function of the hallux during activities of daily living. Pedobarography was carried out using the Musgrave pedobarograph system to detect changes in forefoot loading in comparison to the contralateral normal foot. Fourteen of the 16 patients scored maximally on the hallux metatarsophalangeal-interphalangeal scale and none of the patients noticed functional weakness of the hallux during activities of daily living at a mean follow-up of 43.6 months (range, 5-120 months). Pedobarograph readings showed a trend toward reduction in peak pressure loading on the distal phalanx, but this was not significant for the numbers of patients studied. There was no significant increase in loading of the first or second metatarsophalangeal joints to suggest that transfer metatarsalgia may complicate FHL tendon transfer. According to the results of the study morbidity from FHL transfer should be clinically insignificant.