Two year follow-up of 334 third-generation Minimally invasive Chevron Akin Osteotomies (MICA) in hallux valgus surgery

T.L. Lewis, R. Ray, D. Gordon

Background: There are many different procedures described for the correction of hallux valgus deformity. Minimally invasive surgery has become increasingly popular, with clinical and radiological outcomes comparable to traditional open osteotomy approaches.There is increasing interest in hallux valgus deformity correction using third-generation minimally invasive chevron akin osteotomy (MICA) technique.

Objective: To assess the radiographic correction and 2 year clinical outcomes of third-generation MICA using validated outcome measures.

Methods: This is a prospective single-surgeon case series of 420 consecutive feet undergoing MICA surgery between July 2014 and November 2018. Primary clinical outcome measures included the Manchester-Oxford Foot Questionnaire (MOXFQ), EQ-5D, and the Visual Analogue Pain Scale. Secondary outcome measures included radiographic parameters, and complication rates. 

Results: Pre-operative and 2 year post-operative patient reported outcomes were collected for 334 feet (79.5%). At minimum 2 year follow-up, the MOXFQ scores (mean ± standard deviation (SD)) had improved for each domain: pain; pre-operative 43.9±21.0 reduced to 9.1±15.6 post-operatively (p<0.001), walking and standing; pre-operative 38.2±23.6 reduced to 6.5±14.5 post-operatively (p<0.001) and social interaction; pre-operative 47.6±22.1, reduced to 6.5±13.5 post-operatively (p<0.001). 

At 2 year follow-up, the VAS Pain score (mean ± SD) improved from a pre-operative of 31.3±22.4 to 8.3±16.2 post-operatively (p<0.001). 1-2 intermetatarsal angle (mean ± SD) reduced from 15.4°±3.5° to 5.8°±3.1° (p<0.001) and hallux valgus angle reduced from 33.1°±10.2° to 9.0°±5.0° post-operatively (p<0.001). 

Conclusion: Third-generation MICA showed significant improvement in clinical outcomes at 2 year follow-up and can be successfully used for correction of a wide range of hallux valgus deformities.