Outcome of Bunion Correction with First Tarsometatarsal Arthrodesis in Adult Acquired Flatfoot Deformity Correction

Abstract

Category: Bunion; Hindfoot; Midfoot/Forefoot Introduction/Purpose: Arthrodesis of the first tarsometatarsal (TMT-1) joint is a widely accepted procedure for treatment of hallux valgus (HV) with medial column instability secondary to unstable first ray, midfoot arthritis, and severe or recurrent deformities with high intermetatarsal angles (IMA). This study aimed to evaluate clinical and radiographic outcomes in patients with mild-to-severe HV who underwent TMT-1 arthrodesis and proximal hindfoot correction for adult acquired flatfoot deformity (AAFD). Methods: All patients with symptomatic HV and AAFD who failed conservative management underwent TMT-1 fusion and proximal hindfoot correction (medial displacement calcaneal osteotomy, lateral column lengthening, subtalar fusion, or tibiotalocalcaneal fusion) by one of three senior foot and ankle surgeons at a single tertiary center between January 2006 and December 2018 were included in our retrospective case series. Demographics, clinical outcomes, patient comorbidity information, and radiographic outcomes including hallux valgus angle (HVA), IMA 1-2, hallux valgus interphalangeus angle, distal metatarsal articular angle, and sesamoid station were collected. The primary outcome was change in HVA measured as the difference between final postoperative and preoperative weight bearing HVA measurements. Secondary outcomes were reoperation, minor complications (local wound care, use of antibiotics, and skin dehiscence), and change in radiographic measurements. Results: With an average follow up of 26 months, 155 patients (17.4% male, 82.6% female; average age 59.0 years old, range 18 to 84) met inclusion. The average change in HVA was -18.6 degrees (range +15.8 to -81.0). There was a total of 85 reoperations in 35.5% (n=55; 48 hardware removal). Minor complications were present in 18.7% (n=29; 25 local wound care, 23 use of antibiotics, and 10 skin dehiscence). 44.5% (n=69) had no evidence of recurrent HV while mild, moderate, and severe grade bunions were present in 40.0% (n=62), 5.2% (n=8), and 0.6% (n=1). Improvement in overall bunion grade was maintained in 69.7% (n=108) with no change in 19.4% (n=30). Hallux varus was present in 9.7% (n=15; 3 underwent TMT-1 arthrodesis). Conclusion: The present study demonstrates a significant improvement in HVA following TMT-1 arthrodesis and proximal hindfoot correction for AAFD. The majority of patients undergoing TMT-1 arthrodesis and proximal hindfoot correction for AAFD obtain and maintain improvement in the radiographic severity of their bunions. However, patients should be counseled concerning expectations with regards to outcomes associated with complex AAFD reconstructions.