Outcomes after 100 Minimally Invasive Chevron/Akin Procedures and Strategies to Optimize Outcomes

by Steven Neufeld MD, Hanif Hussaini MD, Dan Dean MD

INTRODUCTION

Minimally invasive surgery (MIS) is being increasingly used for bunion deformity correction. Third generation minimally invasive chevron/akin (MICA) techniques are used but limited patient outcome data has been reported. This study looked at 100 percutaneous extra-articular distal metatarsal osteotomies for mild to moderate bunion deformity. The study reports on the degree of deformity correction, foot width changes, pain control, patient satisfaction, complication rates, and learning curve. It also describes strategies for avoiding the intra-operative and post-operative complications that may arise with MIS bunion surgery.

MATERIALS & METHODS

The participants were the treating surgeon’s first 100 consecutive patients whose bunions were corrected with MICA procedures. Outcome measures including pre and post-operative intermetatarsal angles (IMA), hallux valgus angles (HVA), visual analogue scale (VAS) scores, and complication rates were retrospectively assessed. Statistical analysis was done utilizing Student’s t-test for continuous variables and chi square test for categorical variables.

RESULTS

Average patient follow-up was 94.8 days. VAS scores dropped one week post-operatively, from 5.1 pre-operatively to 2.4 (p<.05). IMA improved from 12.6 degrees to 5.6 at final follow-up (p<.05), while HVA improved from 26.8 degrees to 12.6 (p<.05).  Bony foot width improved from 92.4 mm to 87.1 (p<.05), and soft tissue foot width improved from 104.1 mm to 100.0 (p<.05).  The re-operation rate was 4%, including 2 hardware removals, 1 irrigation and debridement, and 1 neurolysis.  The minor complication rate was 16%.  Ninety-three percent of patients reported good or excellent satisfaction with the procedure.  Complication rates and patient satisfaction scores were similar between the first and second half of patients (p>.05).

Burr in position to complete distal chevron osteotomy, with pre-positioned k-wire

CONCLUSION

In our experience, the MICA osteotomy is a safe and reproducible technique, associated with rapid improvement in pain scores, early weight-bearing, significant deformity correction, high patient satisfaction, and low frequency of complications.  Additionally, the learning curve for the procedure is not as steep as previously reported.

Pre-operative (left) and post-operative (right) X-rays of foot after MICA procedure

Pre-operative (left) and post-operative (right) photos of foot after MICA procedure