Subtalar Kinematics Following Resection of Tarsal Coalition

Abstract

Pain relief and functional improvement in the short term have been demonstrated in the majority of patients with tarsal coalition following resection. Recreation of normal subtalar kinematics is an important goal in these patients as well, and may have long term implications. The purpose of our study was to examine whether kinematic variables of foot motion are normalized following resection of tarsal coalition. This study compared three groups: nine candidates for resection of tarsal coalition, nine patients between 2 and 4 years after bar resection, and nine control subjects. Ankle hindfoot scoring was evaluated according to the AOFAS. Kinematic analysis of subtalar motion in the coronal plane and in the sagittal plane was performed using a computerized gait analysis system. Significantly increased passive subtalar range of motion and AOFAS ankle hindfoot scoring were demonstrated in postoperative subjects relative to preoperative subjects (p = 0.000). However, the kinematic analysis performed during walking, revealed similar, severe restriction of the subtalar eversion-inversion motion in postoperative and preoperative subjects. Angular velocity of the subtalar motion was also similar in both coalition groups, and was significantly increased compared with control. Kinematic analysis of foot motion in the sagittal plain demonstrated improved motion in postoperative subjects, which was comparable with the control group. Foot kinematics are not recreated following tarsal coalition resection, despite the favorable clinical outcome observed. Following resection of a tarsal coalition, patients continue to be subjected to increased loading and torque in their subtalar and adjacent articulations. This may promote further articular deterioration in the long term. Additional operative procedures or rehabilitation protocols should be examined to improve foot kinematics in this population.