In situ tibialis posterior to flexor digitorum longus tendon transfer for tibialis posterior tendon dysfunction: a simplified surgical approach with outcome of 11 patients.

Outcomes for 11 patients who underwent an in situ tibialis posterior tendon to flexor digitorum longus tendon side-to-side anastamosis as the sole procedure for stage 2 tibialis posterior tendon dysfunction were reviewed. The average follow-up was 34.4 months. Using the American Orthopedic Foot and Ankle Society hindfoot rating scale, a mean improvement of 39.3 points was achieved, with preoperative scores of 38.8 improving to 78.1 postoperatively. Good to excellent results were achieved in nine patients. The in situ side-to-side anastamosis is technically easier to perform, has less tissue trauma, and compares favorably with other soft-tissue procedures and reconstructions for stage 2 tibialis posterior tendon dysfunction. Performing this transfer alone, while leaving the flexor digitorum longus tendon intact, theoretically provides a stronger transfer as the length-tension relationship of the flexor digitorum longus tendon is maintained near its physiologic level. The procedure can consistently restore inversion ability to the rearfoot and stop the progression of tibialis posterior tendon dysfunction.