Radiographic Correction of Bunionette Deformity using Minimally Invasive Fifth Metarsal and Akinette Osteotomy

Abstract

Category: Midfoot/Forefoot; Lesser Toes; Other Introduction/Purpose: Bunionette Deformity is defined as a painful lateral prominence of the fifth metatarsal head. Conservative treatment entails footwear and activity modification. Symptoms can be exacerbated in the athletic population and activities with specific footwear such as cycling, winter sports and water sports. In refractory cases, patients may pursue operative intervention. Historically, open surgical correction carried risks of wound complications, prolonged recovery time, and nonunion risk. Minimally invasive techniques have gained popularity due to the decreased risk of wound complications, preservation of blood supply and healing potential, and faster operative and recovery times. The purpose of the current study is to examine radiographic and clinical outcomes of minimally invasive bunionette correction with a sliding distal 5th metatarsal osteotomy and lateral closing wedge proximal phalanx (Akinette) osteotomy. Methods: A retrospective review examined 36 feet in 28 patients who underwent minimally invasive bunionette correction from 01/2021 to 12/2021. The study patients were treated at a single center by 3 participating providers trained in minimally invasive techniques. All patients underwent a distal 5th metatarsal osteotomy and Akinette osteotomy of the proximal phalanx. Length of follow up ranged from 3 to 12 months. Radigraphic measurements including 4,5 intermetatarsal angle (IMA), 5th metatarsophalangeal angle, and osteotomy displacement (mm) were compared pre and postoperatively. Patients were asked to complete postoperative satisfaction survey and lesser toe American Orthopaedic Foot & Ankle Society (AOFAS) score. Results: Preliminary analysis shows a radiographic 4,5 IMA correction of 4.9 degrees to 3.4 degrees. Fifth metatarsophalangeal angle was corrected from 20.3 degrees preoperatively to 5.3 degrees postoperatively. Average medial displacement of the metatarsal osteotomy was 2.64 mm. There was one nonunion of the 5th metatarsal in a revision case that had previously been treated at an outside facility with open techniques, which was treated with bone grafting. Two other patients underwent revision surgery for complications from concomitant procedures that were performed (1 lapidus nonunion and 1 lapidus wound dehiscence). There were no wound or neurovascular complications involving the 5th ray. Conclusion: Our data shows that minimally invasive bunionette correction with sliding 5th metatarsal and Akinette osteotomy leads to reliable radiographic correction and clinical improvement. This operation has favorable safety profile with low incidence of complications and a high union rate.