Use of a Geometric Formula to Improve the Radiographic Correction Achieved by the Scarf Osteotomy

Background: Many procedures for hallux valgus treatment have high recurrence rates, often related to operative considerations such as accuracy of deformity correction, soft tissue balancing and sesamoid alignment. Inadequate distal metatarsal-articular angle (DMAA) correction is common with uni- and bi-planar osteotomies which principally address the inter-metatarsal angle (IMA). The scarf osteotomy is a tri-planar osteotomy which corrects the DMAA and IMA, thereby achieving a more anatomical correction and potentially reducing the recurrence rate. Our hypothesis was that by controlling the length and relative proximal and distal translations of the scarf with a geometric formula, more accurate correction of the IMA and DMAA is possible. Methods: A formula was generated to determine the specific adjustments required to correct the deformity. A prospective trial was performed to assess the accuracy of this formula. Thirty-four adult patients were enrolled in the study. Seventeen patients underwent a standa...