Fifth Metatarsal Bunionette Correction Using a Stable Intramedullary Device
Authors: Kay David B. , Sabetta James A. 
Published: January 2022

Category: Lesser Toes Introduction/Purpose: Fifth metatarsal osteotomies for correction of a bunionette deformity are stabilized with a variety of techniques. The fifth metatarsal is a small bone with a unique blood supply and anatomy. Most of the described osteotomies are distal, making stable fixation technically demanding. The use of minimal incision surgery (MIS), also presents further challenges in the placement of stable fixation and current recommendations are to use either no fixation or intramedullary Kirschner wire fixation. Extensive translational osteotomies have not had documentation on healing as have first metatarsal osteotomies. This paper presents the results of 2 fellowship-trained orthopedic surgeons utilizing a new surgical implant that is both intramedullary and intramedullary. The patients were assessed with an endpoint of radiographic healing. Methods: A consecutive series of 21 de-identified patients who underwent a fifth metatarsal osteotomy for bunionette correction were radiographically followed until healing. Each patient was pre-operatively classified following the Coughlin classification of bunionette deformity. Postoperative radiographic assessments were made to include: 1. Bridging bone 2. The formation of medial bridging from the metatarsal head to the shaft. 3. Change in the 4-5 Intermetatarsal angle. Also, there was made a notation of complications: Time to weight-bearing, pain, and function were not assessed. There was only a small sample of patients that were treated with an isolated bunionette procedure. The other procedures were impactful and would skew the functional results. We also evaluated for hardware complaints that would need removal. Results: 19 patients, 21 feet were evaluated with ages ranging from 51-77 years (Avg 63 years). 17 women and 2 men. Only one patient was a revision of prior surgery. Only 4 patients had an isolated bunionette correction. The other surgical procedures including; double osteotomy bunionectomy, distal metatarsal osteotomies (MIS), phalanx osteotomies of the great and lesser toes, Lapidus bunionectomy, first metatarsophalangeal arthrodesis. Coughlin grading; one Grade one, ten Grade 2, ten Grade 3. The average time to radiographic healing was 8 weeks. 5 patients underwent a traditional open incision and a chevron osteotomy with a saw, the remainder of the osteotomies were percutaneous transverse osteotomies performed with a 2x12mm Shannon burr. The mean 4-5 intermetatarsal angle improved from 10 degrees preoperatively to 3 degrees at follow-up. The amount of shift varied whether the lateral eminence was or was not excised. The numbers are not large and meaningful statistics are difficult to extrapolate. Conclusion: This is the first documented use of a novel surgical implant designed specifically for fifth metatarsal osteotomies used for bunionette correction. The implant is simple to use, provides for stability to prevent malunion and nonunions. It is low profile and has not caused irritation requiring removal in this pilot group. It is versatile and can be used with either an MIS approach and a transverse osteotomy or a classic open incision with a chevron osteotomy.