Midterm Outcomes of Sliding Distal Metatarsal Minimally Invasive Osteotomy to Treat Bunionette Deformity

Abstract

Background: Bunionette deformity is described as a painful bony prominence on the lateral aspect of the fifth metatarsal head. The present study prospectively assessed the clinical, functional, and radiographic outcomes of sliding distal metatarsal minimally invasive osteotomy (S-DMMO) used in a large series of patients with a midterm follow-up period. Methods: From December 2015 to December 2018, we evaluated 74 feet (57 patients). Radiologic (4-to-5 intermetatarsal angle, fifth metatarsophalangeal angle, the fifth metatarsal head width, lateral deviation angle, fifth metatarsal length, medial displacement, and elevation), clinician-reported scores (AOFAS score, visual analog scale [VAS]) and patient-reported outcomes measure (Foot and Ankle Ability Measure [FAAM] activities of daily living [ADL], FAAM sports, Manchester-Oxford Foot Questionnaire [MOXFQ], and patient satisfaction survey) were included in the analysis. The time to bone union was also assessed. Results: The average 4-to-5 intermetatarsal angle improved from 11.1 degrees preoperatively to 4.5 degrees postoperatively ( P < .001), whereas the average fifth metatarsophalangeal angle improved from 15.7 degrees preoperatively to 4.8 degrees postoperatively ( P < .001). The lateral deviation angle was found to be 2.2 degrees. The fifth metatarsal length decreased from 66.6 to 64.3 mm postoperatively. The average initial medial displacement was 4.67 mm preoperatively and 4.54 mm at final follow-up. The elevation of the fifth metatarsal head was 1.08 mm. The American Orthopaedic Foot & Ankle Society score improved from 54.3 ± 20.86 points preoperatively to 93.4 ± 17.3 ( P < .001). VAS score decreased from 7.9 to 0.7 ( P < .001). Also, FAAM ALD, FAAM Sport, and MOXFQ showed statistically significant differences ( P < .001) between preoperative and postoperative periods. Patients found the procedure excellent in 89.1% of cases, very good in 5.4%, and good in 5.4%. Bone union was obtained at 8.1 weeks. Conclusion: The most important finding of the present study is that S-DMMO showed improvement in function and pain associated with a high satisfaction rate. Also, we found substantial capacity to correct deformities and a low incidence of complications. Level of Evidence: Level IV, case series.