Abstract
Category:
Bunion; Midfoot/Forefoot
Introduction/Purpose:
The majority of hallux valgus (HV) corrections have been historically performed via a two-dimensional, transverse plane-focused approach, which has demonstrated high rates of recurrence. Recently there has been a trend towards less-invasive approaches and an instrumented 1st TMT system was developed to perform a triplanar 1st TMT arthrodesis through a mini-open incision. Therefore, the purpose of this study is to assess the radiographic and patient-reported outcomes for HV correction performed with this system through a mini-open approach (≤4cm) with early return to weightbearing.
Methods:
This is an interim analysis of a prospective multicenter study on patients with symptomatic HV and no prior history of HV surgery on the operative foot. Patients were treated with an instrumented 1st TMT procedure through a mini-open (≤4cm) dorsal incision (which is approximately 50% smaller than the system’s prior-generation open incision) utilizing a biplanar locking plate construct with protected early weightbearing. The primary endpoint of this study is radiographic recurrence of HV, with recurrence reported using two different thresholds commonly utilized in the literature: post-operative HVA >15° and HVA >20°. Changes in radiographic measurements, return to weightbearing and activities, Manchester-Oxford Foot Questionnaire (MOxFQ), patient-reported pain (VAS), and forefoot circumference were also evaluated for statistically significant post-operative improvements through 12-month follow-up.
Results:
105 patients (mean [range] age: 41.0 [14-57] years) underwent a mini-open TMTA, with 92 and 70 patients completing 6- and 12-month visits, respectively. Mean (SD) incision length was 3.5cm (0.27). Mean (95% CI) time to protected weightbearing and unrestricted activity were 7.9 (6.7, 9.1) days and 3.6 (3.4, 3.8) months, respectively. Significant improvements in HVA, IMA, and TSP were maintained through 12 months (Table 1). Applying recurrence definitions of HVA >15° and >20°, 12-month recurrence rates were 4.8% (3/62) and 0% (0/62), respectively. Significant improvements in VAS and MOxFQ were observed through 12 months (N =65). Twelve-month mean (95% CI) change in forefoot circumference was -0.8cm (-1.2, -0.5), N =64. One (1.0%) of 105 patients required reoperation (HWR due to pain) and no patients experienced symptomatic nonunion.
Conclusion:
The interim results of this prospective, multicenter study on a mini-open 1st TMT system with early weightbearing demonstrated statistically significant improvements in radiographic alignment and patient-reported outcomes, and minimal forefoot swelling. This study will follow the patients for a total of 24 months postoperatively.
