Minimally Invasive Distal Oblique Diaphyseal Osteotomy for Bunionette Deformity Correction: Does Completing the Osteotomy Make a Difference? Radiographic and Clinical Outcomes of 43 Patients

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: There has been increasing interest in the use of minimally invasive osteotomy techniques for bunionette (Tailor’s bunion) correction. The aim of this study was to investigate the clinical and radiographic outcomes following an unfixed minimally invasive oblique distal diaphyseal osteotomy for bunionette deformity correction. Methods: 43 patients (mean age 54.2 ± 17.1) underwent minimally invasive oblique osteotomy for bunionette deformity correction by a single surgeon over a course of 4 years. We collected data on radiographic parameters (Inter-metatarsal angle(IMA), metatarso-phalangeal angle(MPA), pre-operative Coughlin classification, whether the osteotomy was completed or the lateral cortex was still intact and post-operative callus formation) and Patient Reported Outcome Measures (PROMs) prospectively pre-operatively and at a mean of 18 months follow up. Results: 16 patients had a Coughlin Type 1 deformity, 8 Type 2, 19 Type 3. The patients showed a significant reduction in IMA from 10.0±2.6 to 5.2±1.9 and MPA from 13.8±5.3 to 4.9±2.8. 30 patients had a complete osteotomy, 13 patients had a hinge osteotomy with the lateral cortex remaining intact. 41% of patients had callus equivalent to 150% of the metatarsal width or over at 6 weeks follow up, this reduced to 15% at 6 months and 0% at 12 month follow up. The Manchester Oxford Foot Score significantly improved in all domains as did the VAS Pain score. Conclusion: Minimally invasive oblique osteotomy for bunionette deformity correction seems a safe and effective procedure significantly improving radiographic and clinical outcomes. Whether or not the osteotomy is completed does influence callus formation but does not significantly affect the radiographic or clinical outcomes.