Midterm results and complications after minimally invasive distal metatarsal osteotomy for treatment of hallux valgus.

BACKGROUND: Minimally invasive distal metatarsal osteotomy (MIDMO) is a common technique used to correct the hallux valgus deformity, but controversy remains regarding the expected outcomes of this surgery. METHODS: Seventy-two patients (85 feet) suffering from hallux valgus underwent MIDMO with a modified Bösch technique. Patients were prospectively evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) hallux score, and the AOFAS recovery rate was calculated. Before surgery and at follow-up, the hallux valgus (HVA), intermetatarsal (IMA), and distal metatarsal articular (DMAA) angles were measured, and the severity of disease was categorized according to the preoperative HVA. The tibial sesamoid position and articular congruence were evaluated. Postoperative complications were noted. RESULTS: After an average follow-up of 73.3 ± 38.1 months, the total AOFAS score improved from 47.6 ± 13.3 to 87.3 ± 11.5 (P < .001). The HVA decreased from 34.7 ± 8.2 to 14.8 ± 7.8 degrees, the IMA from 14.7 ± 4 to 6.6 ± 3.6 degrees, and the DMAA from 20.9 ± 9.8 to 9 ± 6.6 degrees (P < .001 for all). Postoperative improvement in AOFAS was inversely related to the preoperative severity of disease (P < .001, β = -.378). Sixteen (18.8%) deformity recurrences were noted, 9 of which were observed in patients with preoperative HVA more than 40 degrees. Worse preoperative congruence of the metatarsophalangeal joint and tibial sesamoid position correlated with a higher rate of recurrence of the disease after surgery (P = .001, β = -.353 and P < .001, β = .427, respectively). CONCLUSIONS: Satisfactory clinical and radiological results can be expected after MIDMO, but caution should be exercised when using this technique because of the likelihood of possible complications (29.4% overall complication rate). Predictors of surgical outcomes can be used to select the best candidates for this surgery.