Surgical reconstruction of posterior tibial tendon dysfunction: Prospective comparison of flexor digitorum longus substitution combined with lateral column lengthening or medial displacement calcaneal osteotomy

Abstract

Posterior tibial tendon dysfunction (PTTD) may require surgical intervention when nonoperative measures fail. Different methods of bony reconstruction may supplement tendon substitution. This study compares two types of bony procedures used to reinforce reconstruction of the posterior tibial tendon—the lateral column lengthening (LCL), and the medial displacement calcaneal osteotomy (MDCO). Twenty patients with PTTD were evaluated before and after scheduled reconstruction comprised of either flexor digitorum longus (FDL) substitution combined with MDCO (MDCO group, 14 patients) or FDL substitution with LCL fusion or osteotomy (LCL group, 6 patients). Foot/ankle kinematics and temporal–spatial parameters were analyzed using the Milwaukee Foot Model, and results were compared to a previously evaluated normal population of 25 patients. Post-operatively, both patient groups demonstrated significantly improved stride length, cadence and walking speed, as well as improved hindfoot and forefoot position in the sagittal plane. The LCL group also demonstrated greater heel inversion. All post-operative subjects revealed significant improvement in the talo-MT1 angle in the A/P and lateral planes, calcaneal pitch and medial cuneiform-MT5 height. Surgical reconstruction of PTTD with either the LCL or MDCO shows comparable improvements in gait parameters, with better heel inversion seen with the LCL, but improved 1st ray plantarflexion and varus with the MDCO. Both procedures demonstrated comparable improvements in radiographic measurements.