Transposition of the tendon of the M. tibialis posterior as an effective operative treatment of a drop foot

Objective. To evaluate the results of transposition of the tendon of the M. tibialis posterior in patients with a drop foot. Design. Descriptive, retrospective and follow-up investigation. Methods. Surgical treatment was carried out in 12 patients with a drop foot (9 women and 3 men, with an average age of 37 years) in the period 1986-1998. The aetiology of the drop foot was a traumatic or iatrogenic lesion of the peroneal nerve or sciatic nerve in 9 patients and in 3 patients spina bifida occulta, leprosy and a herniation of a lumbar disc respectively. None of the patients had important comorbidity. Treatment consisted of lengthening the Achilles tendon according to Huckstep, transposition of the tibial posterior tendon in two tails to the dorsomedial and dorsolateral side of the foot, and six weeks of immobilisation in plaster of Paris. Results. The postoperative period was without complications. The treatment improved the heel-toe steppage gait in all patients. None of the 10 patients who had used an orthosis preoperatively still used it at the time of the follow up. Fifty per cent of the patients acquired a dorsiflexion of the foot of more than 0°. The results were in accordance with those in the literature. Conclusion. Transposition of the tibial posterior tendon is a worthwhile alternative for those patients with a drop foot (and without important comorbidity) who cannot walk satisfactorily with an ankle-foot orthosis.