RESUMEN
BACKGROUND: Drop foot deformity is a common problem with severe restrictions in quality of life and impairment of daily activities. A technique of posterior tibial tendon transfer through the interosseus membrane and fixation to the anterior tibial and the long peroneal tendon "Bridle procedure" (stirrup-plasty) offers a physiological alternative to surgical correction. METHODS: Data of 53 consecutive patients treated by stirrup-plasty were acquired from patient's charts; 31 were interviewed with standardized questionnaires; 20 were examined physically; 19 received pedobarography, and 8 underwent dynamometric muscle function tests. Follow-up time averaged 6.5 years. RESULTS: The mean range of motion (ROM) in the ankle joint was 8° dorsiflexion and 15° plantar flexion. Most patients achieved plantigrade foot position and the majority developed gait without orthotic devices. As expected, maximum dorsiflexion torque averaged a third of the non-operated leg, according to reduced muscle diameter and strength of the transferred muscle. Pressure distribution of the sole during gait was not relevantly altered by the tendon transfer compared to the non-operated leg. Most patients were satisfied with the operative results and reported a significant increase in quality of life. CONCLUSIONS: Fusion of the transposed posterior tibial, anterior tibial and the peroneus longus tendon prevents drop foot deformity sufficiently. The stirrup mechanism, in combination with tenodesis of the toe extensors, provides a balanced foot and avoids equinovarus and cavus deformity without immobilizing the ankle joint. Improvements in quality of life parameters justify the risk of the operative procedure for the patient.