Clinical Deformity Correction Following Minimally Invasive Akin Osteotomy Fixated with Single 2.5mm Screw, A Prospective Study

Submission Type: Hallux Valgus Research Type: Level 2 - Prospective comparative study, Meta-analysis of Level 2 studies or Level 1 studies with inconsistent results Introduction/Purpose: The medial closing wedge osteotomy of the proximal phalanx, known as the Akin osteotomy, is a common procedure in combination with metatarsal osteotomies and soft tissue realignment procedures to achieve hallux valgus deformity correction. With developments in surgical instrumentation, the option to perform osteotomies percutaneously has grown in popularity. There is limited data analyzing individualized performance and maintenance of correction with the addition of a percutaneous Akin osteotomy. Prior studies have referenced radiographic alignment and outcomes following minimally invasive Akin osteotomy. This is the first prospective study analyzing both radiographic and clinical alignment, as well as outcomes scores using 2.5mm screw fixation for MIS (Minimally Invasive Surgery) correction. Methods: Consecutive subjects were prospectively enrolled prior to percutaneous Akin osteotomy fixated with a single 2.5mm cannulated fully threaded compression screw over a two-year period. Interphalangeal angle (IPA), proximal distal phalanx articular angle (PDPAA), and distance between first and second toes (mm) were recorded. The clinical shift of the Akin osteotomy was measured intra-operatively, and the maintenance of correction documented during follow-up. Patient demographics, visual analog scales, and patient-reported outcome measures were compiled. Results: 86 Akin osteotomies were performed on 83 patients over a two-year period. Median follow-up was 56 (range, 43 to 151) weeks. IPA changed by median -5.0 (interquartile range, -7.5 to 0.5) degrees (P <.001). PDPAA changed by median -4.0 (interquartile range, -7.5 to 0.0) degrees (P <.001). Distance between first and second toes changed by median -6.0 (interquartile range, -7.0 to -3.0) mm (P <.001). VAS Pain Score, MOXFQ, AOFAS, and Coughlin functional scores improved postoperatively. 8 of 86 osteotomies (9%) required removal of painful hardware, and there was 1 (1%) deep infection requiring removal of hardware. 76 (88%) of cases had no complications. There were no proximal phalangeal non-unions. Conclusion: Patients undergoing minimally invasive Akin osteotomy with use of 2.5 mm cannulated fully threaded screws demonstrated improvement in radiographic and clinical alignment as well as improvement in patient-reported outcome measures at the time of initial and final follow-up. Complication rates were low, and incremental improvement in hallux valgus deformity correction was maintained.