Results of an Interim Analysis of a Prospective Multicenter Study Assessing Radiographic and Patient Outcomes Following Triplanar Tarsometatarsal Arthrodesis with Early Weightbearing

CATEGORY: Bunion; Midfoot/Forefoot INTRODUCTION/PURPOSE: The majority of hallux valgus corrections are performed via a uniplanar metatarsal osteotomy approach in which the metatarsal is cut and shifted over in the transverse plane. This approach has demonstrated high long-term recurrence rates. Recent research demonstrates that 87% of hallux valgus deformities are three-dimensional with abnormal frontal-plane rotation of the metatarsal, which cannot be fully addressed with a uniplanar metatarsal osteotomy. While correction at the 1st tarsometatarsal (TMT) joint may provide the optimal surgical approach for 3D anatomic restoration at the apex of the deformity, 1st TMT fusion has historically involved an extended period of non-weightbearing. This study evaluates the clinical, radiographic, and patient-reported outcomes in patients undergoing instrumented triplanar 1st TMT arthrodesis (TTA) with a biplanar plating system and protected near-immediate weightbearing. METHODS: This is a prospective multicenter study that will continue for 60 months post-operatively. Patients between 14-58 years old with symptomatic hallux valgus (intermetatarsal and hallux valgus angles between 10.0-22.0° and 16.0-40.0°, respectively) and no prior hallux valgus surgery on the operative foot are eligible for this study. Patients are treated with an TTA procedure using a biplanar plating system with protected near-immediate weightbearing. Outcomes (radiographic, range of motion (ROM), pain measured by visual analog scale (VAS), Manchester-Oxford Foot Questionnaire (MOxFQ), return to weightbearing and activities) are evaluated post-operatively. Two independent musculoskeletal radiologists reviewed radiographic data. These interim results are limited to patients completing at least 6 weeks of follow-up. RESULTS: At time of data cut-off, 74 patients had undergone TTA with at least 6 weeks follow-up. The majority of patients were women (95%) with mean age 41.7 years. The mean (95% confidence interval) time to protected weightbearing in CAM boot was 8.0 (6.4, 9.7) days, return to work was 19.0 (13.6, 24.4) days, and return to full work was 31.5 (22.7, 40.2) days. There was a significant change in radiographic measures pre vs. post procedure and changes were maintained over time (Table). VAS pain score decreased 4 and 6 months post-procedure by 3.9 (3.2, 4.6) and 4.2 (3.5, 5.0), respectively. The mean MOxFQ Index Score pre-procedure was 53.3 (49.5, 57.1) and at month 6 had decreased to 18.6 (12.9, 24.2). CONCLUSION: These interim findings support that TTA with biplanar plating is successful in correcting the 3D hallux valgus deformity with early return to weightbearing and demonstrated favorable clinical and patient-reported outcomes. Patients were able to return to full, unrestricted work and activities within just a few months and had meaningful pain reduction after surgery. Patients will continue to be followed for up to 60 months. Clinical/radiographic healing at 12 months and recurrence rates at 24 months, as well as complications and patient satisfaction, will be evaluated.