Subcapital Oblique Osteotomy for Correction of Bunionette Deformity

Abstract

Multiple osteotomies have been described for treatment of type I bunionette deformity. This article describes the distal subcapital oblique osteotomy of the fifth metatarsal, as well as a modification that may allow for expanded indications. This osteotomy has demonstrated clinical success, with potential benefits over other procedures for this condition.Level of Evidence: Diagnostic Level 4. See Instructions for Authors for a complete description of levels of evidence. HISTORICAL PERSPECTIVEThe term bunionette describes a prominence in the region of the lateral fifth metatarsal head. The condition was first described by Davies in 1949, 1 and has also been referred to as a Tailor's bunion, due to the seated position assumed by tailors with the leg crossed, which places pressure on the lateral foot. Several anatomic factors have been related to the bunionette deformity. Kelikian 2 described a prominent fifth metatarsal lateral eminence as a cause and likened it to the medial eminence of the first metatarsal head in bunion deformity. DuVries 3 cited 3 separate causes: hypertrophy of the soft tissue overlying the fifth metatarsophalangeal (MTP) joint; a congenitally wide fifth metatarsal head; and lateral bowing of the fifth metatarsal. An additional cause may be splaying of the fifth metatarsal with an increase in the 4-5 intermetatarsal (IM) angle. 1 Common to all of these abnormalities of the fifth metatarsal is a medial deviation of the fifth toe at the MTP joint.The classification scheme described by Coughlin 4 can be used to aid in the decision as to what type of osteotomy is most appropriate for correction of bunionettes. According to this scheme, type I bunionette is that in which there is a prominent lateral eminence of the fifth metatarsal head without significant increase in the 4-5 IM angle or lateral bowing of the metatarsal shaft. Type II bunionette is due excessive lateral bowing of the metatarsal; type III is due to a widened 4-5 IM angle. Many procedures have been described for correction of the bunionette deformity that is due to a large metatarsal head. Lateral condylectomy has been commonly recommended, 1,3,5-7 although most reports are primarily anecdotal in follow-up. Kitaoka and Holiday 7 reported on long-term follow-up on 21 feet in 16 patients and found that although minimal correction of the fifth MTP joint was obtained, the procedure is simple often successful. Nonetheless, 23% of patients reported some residual forefoot pain and the procedure is felt to be limited in its applications. As a result of these limitations, some authors have recommended more extensive resection with fifth metatarsal head resection. 2,[8][9][10][11] Similarly, most of these reports are also anecdotal. McKeever 10 reported success in 60 patients with metatarsal head resection but with minimal objective postoperative evaluation. Kitaoka and Holiday 9 reported 7-year follow-up and found fair or poor results in 82% of patients and complications in 64% including subluxation, transfer lesions, shortening of the toe, a...