Symptomatic bunionette deformity in adolescents: surgical treatment with metatarsal sliding osteotomy

Bunionette deformity is a painful osseous prominence on the lateral aspect of the head of the fifth metatarsal. The purpose of this study is to evaluate the results of a fifth metatarsal sliding osteotomy for the treatment of this deformity in patients under 18 years of age.

We retrospectively evaluated 13 feet in 11 consecutive patients with bunionette deformity treated from January 2003 to January 2008 at 2 referral centers. Mean age was 14.8 years (95% confidence limit, SD 1.5 y); mean follow-up was 32.2 months (95% confidence limit, SD 11.7 mo); and clinical evaluation was made according to the modified American Orthopaedic Foot and Ankle Society (AOFAS) score and the Coughlin score. The IV-V intermetatarsal angle ( IV-V IMA), the width of the forefoot (WF), lateral deviation angle (LDA), and fifth metatarsophalangeal angle (5 MPA) were also measured preoperatively and postoperatively.

The average postoperative AOFAS score was 91 ± 4.1 points. Seven patients (8 feet) had an excellent outcome and 4 patients (5 feet) a good outcome according to the Coughlin scoring rate. The IV-V IMA averaged 12.29 degrees ± 1.5 degrees preoperatively, while postoperatively it was 6.18 degrees ± 1.4 degrees (P<0.0001). The LDA improved from 7.74 degrees ± 1.7 degrees preoperatively to 4.25 degrees ± 1 degree after surgery (P<0.0001). The WF decreased from 8.01 ± 1.3 mm to 7.05 ± 1.3 mm (P<0.0001). The mean 5 MPA decreased from 21.7 degrees ± 4.1 degrees preoperatively to 7.63 degrees ± 3.4 degrees at final follow-up (P<0.0001). One patient developed a superficial infection around a K-wire.

Metatarsal sliding osteotomy is a safe and effective method for the correction of symptomatic bunionette in patients below 18 years of age. Further research is required to compare this approach with other treatment methods in this specific age group.

Case series (Level of evidence, IV).