Outcomes after Minimally Invasive Chevron/Akin Procedure and Strategies to Optimize Outcomes

Abstract

Category: Midfoot/Forefoot; Bunion Introduction/Purpose: Minimally invasive surgery (MIS) is being increasingly used for bunion deformity correction. New third generation minimally invasive chevron/akin (MICA) techniques are used but limited data on patient outcomes have been reported. The goal of this IRB-approved study was to look at outcomes of percutaneous, extra-articular distal metatarsal osteotomies for mild to moderate bunion deformity, including the degree of deformity correction obtained, patient pain control, and complication rates. We also describe strategies for avoiding the intra-operative and post-operative complications that may arise with MIS bunion surgery. Methods: The participants were the treating surgeon’s first 75 consecutive patients 18 years and older who were treated with MICA procedures. Via retrospective chart review, outcome measures including pre and final post-operative intermetatarsal angles (IMA), hallux valgus angles (HVA), visual analogue scale (VAS) score, and complication rates were assessed. Statistical analysis was done utilizing student’s t-test for continuous variables and chi square test for categorical variables. Results: Average follow-up was 105.0 days. VAS scores dropped one week post-operatively, from 5.4 pre-operatively to 2.5 (p< 0.05). IMA angles improved from 12.7 degrees (range 6.1-18.1) pre-op to 6.1 (range 1.2-12.5) at final follow-up (p< 0.05). HVA angles improved from 27.2 degrees (range 9.7-43.4) to 10.4 (range 1.3-25.9) (p<0.05). A major infectious complication occurred in one patient, requiring operative irrigation/debridement and hardware removal. Another patient had a DVT treated successfully with medication. Minor complications included intra-operative fracture (3 patients), persistant paresthesias (3), cellulitis (1), minor loss of reduction (2), hardware prominence/backout (3) and medial prominence pain (3). One patient had surgical removal of a prominent screw head one year after surgery. Complication rates were similar between the first and second half of patients chronologically. Conclusion: Our data suggests that MICA osteotomies are associated with rapid, significant improvement in pain scores, significant deformity correction, and low frequency of major complications. While there is a learning curve, MICA is a reproducible technique, is safe, and allows immediate post-operative weightbearing. All osteotomies achieved union, and there were no tendon injuries. Only two patients required a second surgery. We also present strategies to avoid and limit pitfalls and complications encountered with the procedure. Although our data is exciting, additional studies looking at long-term outcomes, larger sample sizes, and more physicians should be conducted.