Medial Displacement Osteotomy Performed Concurrently with Triple Arthrodesis Improves Pain and Mobility in Patients with Rigid Flatfoot Deformity and Hindfoot Valgus

Abstract

Category: Hindfoot, Midfoot/Forefoot, Flatfoot Introduction/Purpose: Progression of flatfoot deformity and arthritis affects 6-38% of patients with posterior tibial tendon dysfunction treated with a triple arthrodesis. Current theory suggests that undercorrection of hindfoot valgus places abnormal stresses on the deltoid ligament and tibiotalar joint, contributing to the development of increased valgus tilt of the ankle joint or collapse of the medial arch. No large series to our knowledge has attempted to assess the potential benefit of the prospective correction of hindfoot valgus at the time of the triple fusion. Here we analyze the outcomes of 31 unilateral Stage III or IV rigid flatfoot corrections performed with concurrent medial displacement osteotomies. Methods: In an institutional review board approved retrospective study, a total of 31 feet in 31 patients were operated upon from 1/1/2009 to 1/1/2016 by a single surgeon at a large academic medical center. American Orthopaedic Foot & Ankle Society hindfoot scores and visual analog pain scores (VAS) were obtained prior to surgery and at the final post-operative follow-up where available). Foot and Ankle Ability Measure (FAAM) scores were available for 17 (54.8%) of patients. Patient demographic data, including age, body mass index (BMI), charlson comorbidity score, smoking status, and HbA1c where available were recorded. Additional surgical outcomes of interest included a return to unassisted mobility in a shoe or boot, infection and wound complication rate, 90 day re-admissions and revision/subsequent procedures. Pre-and post-operative data were analyzed using Student’s t-test for continuous variables, and Fisher’s exact test for categorical variables using Graphpad Prism (LaJolla, CA). Results: Patient demographic data is demonstrated in figure 1. Average follow-up was 1.3 ± 1.1 years (range .5 to 6.0 years). Average Pre-operative AOFAS scores available from 23/31 (74.2% of patients) averaged 33.5, with 1-year post-operative scores (8/31, 25.8%) of 76.8 ± 4.6 (p < .0001). VAS scores decreased from 6 ± 2.9 to 2 ± 2.7 (p < .0001). Superficial infections were treated in 3/31 (9.7%) of patients, while wounds developed in 6.5%. Mobility without assistive modality in a shoe or boot was reported by 30/31 (96.8%) patients, with one patient requiring a walker. No 90-day readmissions occurred, no amputations occurred, and a single patient returned to the OR 393 days after admission for symptomatic hardware removal. Conclusion: Here we demonstrate in a large retrospective analysis that performing a medial displacement osteotomy in patients with hindfoot valgus in the setting of rigid flatfoot deformity results in nearly universal remobilization, substantially improved functional outcomes, and significantly decreased pain. Few patients had wound complications or infections, and no revision reconstructions were required. Limitations to this study include inconsistent post-operative reporting, and a lack of long term post-operative outcomes. Further work includes a re-surveying of this patient base for updated patient outcomes, as well as quantitative radiographic analysis.