Peroneal strength as an indicator in selecting route of tibialis posterior transfer for foot drop correction in leprosy.

OBJECTIVES: Tibialis posterior tendon transfer (TPT) technique, using either the Circum-tibial (CT) or Inter-osseus (IO) route is the standard surgical technique to correct foot drop. The selection of the route of transfer is usually dependent on the surgeon's preference. This study aims to identify criteria to help make that selection.

SUBJECTS AND METHODS: A study was carried out on 381 feet during the period 1999 to 2010. All the patients operated during this period were included in the study. The CT route was used for those with peronei power 4 or 5, while the IO route was used when peronei power was 3 or less.

RESULTS: In this case series the mean effective range of motion (above 90 degrees) was 11 and 12 degrees in CT and IO routes, respectively. The results were comparable in terms of rest position, active dorsiflexion and effective range of motion. All patients had a post-operative heel to toe gait, except for one of the 381 operated feet. Only three of the 381 feet had a reduction in navicular height of more than 2 cm, the medial arch being maintained in the others.

CONCLUSIONS: TPT is a standard procedure to correct foot drop deformity in leprosy. Pre-selection for route of transfer, CT or IO, based on peronei strength avoids the complication of iatrogenic inversion. The technique of insertion and routine tendo-achilles lengthening provides a good range of movement. The deep tunnelling has not compromised the results, while giving excellent cosmetic appearance.