Outcome of the modified Lapidus procedure for hallux valgus deformity during the first year following surgery: A prospective clinical and gait analysis study

Background: The modified Lapidus procedure is a surgical option to treat moderate to severe hallux valgus deformity with good radio-clinical outcome. However, comprehensive biomechanical outcome evaluation of this surgery at mid-term follow-up is missing. This study assesses and compares the radio-clinical and gait outcome at 6 and 12 months following modified Lapidus procedure. Method: Ten consecutive female patients with moderate to severe hallux valgus who underwent modified Lapidus procedure participated in the study. Comprehensive gait assessment was performed preoperatively, at 6 and 12 months postoperatively. Gait parameters including spatiotemporal, kinematics and plantar pressure were analyzed using pressure insoles and 3-dimensional inertial sensors. Outcome was evaluated using two clinical questionnaires, i.e. the American Orthopaedic Foot and Ankle Score and the Foot and Ankle Ability Measure, and X-rays. Findings: Three spatiotemporal, two kinematics, and seven plantar pressure parameters significantly improved between 6 months and 12 months postoperatively. Significant improvement in radiological and clinical outcome was reported at 6 and 12 months. The Foot and Ankle Ability Measure showed non-significant improvement at 12 months. Interpretation: The outcome of this study is consistent with the previously reported good clinical and radiological results at one year following Lapidus for moderate to severe hallux valgus. Twelve gait parameters demonstrated that outcome improves from 6 months to 12 months postoperative with room for further improvement at long term. The gait outcome in this study confirms the longer rehabilitation period following modified Lapidus procedure. Studies with a larger sample size are required to confirm these findings.