Background: There are limited studies on the long term outcome of Mitchell's osteotomy for hallux valgus deformity. We present the long term results of 204 cases.
Materials and methods: Postoperative clinical and radiological evaluation with a mean follow up of 12.9 years was performed on patients with preoperative hallux valgus angles (HVA) of up to 50 degrees and intermetatarsal angles (IMA) of up to 20 degrees. Two crossed Kirschner wires were used to fix the capital fragment; lateral soft tissue release performed when deemed necessary. Comparisons were made between the pre- and postoperative measurements using a Mann-Whitney U-test. Statistical significance was defined at p < 0.05.
Results: The mean AOFAS score improved from 49.6 to 87.9 points (p = 0.004). There was significant improvement in the HVA and IMA, 33.8 degrees versus 16.1 degrees (p = 0.002) and 15.2 degrees versus 8.2 degrees (p = 0.004), respectively. Fifty-seven cases (27.9%) had preoperative HVA greater than 40 degrees but only 16 required lateral soft tissue release with no significant difference in the postoperative HVA (21.3 versus 20.8, p = 0.08). There was a significant change in lateral metatarsalgia and symptomatic callosities (18.3% versus 11.8%, p = 0.023). In 97.6% of cases the patients were satisfied with the overall result. Revision surgery was performed in five cases (2.5%).
Conclusion: Mitchell's osteotomy was a reliable technique with successful outcome and low complication rate when performed with Kirschner wire fixation and lateral soft tissue release when appropriate. It may also be successfully performed with hallux valgus angles greater than 40 degrees.