First metatarsal extracapsular osteotomy to treat moderate hallux valgus deformity: the modified Wilson-SERI techinique

From February 2017 to December 2018, 20 patients (a total of 20 feet) had undergone the proposed modified Wilson-SERI osteotomy technique, for moderate hallux valgus. The mean age of patients was 58,25 years (range 19 to 78). The hallux valgus angle (HVA), the intermetatarsal angle between first and second metatarsal bone (IMA) and the distal metatarsal articular angle (D.M.A.A) were measured. The feet were assessed based on the scoring system used by Broughton and Winson and by the American Orthopedic Foot and Ankle Society (AOFAS) hallux-metatarsophalangeal-interphalangeal scale. All twenty one patients were followed up postoperatively for a minimum of 12 months. No patient was lost at follow-up. The mean HVA angle decreased significantly from 31,1° before surgery (range 22.9°-40°SD 5.0) at 11,2° (range 2.5° to 22.0°SD 5.3) at twelve months follow up. The mean IMA angle decreased significantly from 12,5° (range 8.0°-18.6°SD 3.8) before surgery at 7,4° (range 3.4°-14.0°SD 2.5) at twelve months follow up. The mean DMMA angle decreased significantly from 15.1° (range 5.3° to 20.0°SD 4.4) before surgery at 7,4 °(1.5° - 10.7°SD 2.5) at twelve months follow up. The mean score according to the AOFAS forefoot was increased from 22,1 (range 13-30 SD 5.0) to 88,2 (Range 77-96 SD 5.2) (p<0.0001). No complications, like dislocations, avascular necrosis of the first metatarsal and deep venous thrombosis, were observed in the post-operative period. We consider the Wilson-Seri procedure as a low cost minimal invasive and stable technique that could be a valid alternative to the various metatarsal osteotomies in the treatment of moderate hallux valgus deformity. Short term results at twelve months after surgery are quite satisfactory but further studies are necessary, to better comprehend an overall outcome of such approach in the long run.