Comparison of Clinical and Radiological Results of Two Fixation Materials after Distal Chevron Osteotomy for Hallux Valgus? - Two Kirschner Wires versus Single Screw Fixation.

PURPOSE OF THE STUDY Although distal chevron osteotomy (DCO) is considered as an intrinsically stable osteotomy, various fixation methods have been used to date. The purpose of this study was comparison of two commonly used methods in DCO, Kirschner (K)-wire and titanium fully threaded headless cannulated screw fixation, based on the clinical and radiological results, and their complications. MATERIAL AND METHODS Thirty patients were included in K-wire group and 36 patients were included in screw group. Mean age was 43.4 11.1 (rage; 19-65) years, and mean follow-up was 21.2 5.5 (range; 12-35) months. American Orthopaedic Foot Ankle Society (AOFAS) metatarsophalengeal-interphalangeal score was used for clinical evaluation. For radiological evaluation, hallux valgus angle (HVA), first-second intermetatarsal angle (IMA), distal metatarsal articular angle (DMAA), medial sesamoid grade (MSG), and lateral sesamoid distance (LSD) to mid-axis of the second metatarsal were measured for all patients on both preoperative and postoperative final follow-up radiographs. RESULTS Mean AOFAS scores were significantly improved and radiographic measurements were significantly reduced at postoperatively in both groups (p< 0.01 for AOFAS, HVA, IMA, DMAA and MSG; p = 0.01 for LSD). Mean preoperative and mean postoperative, as well as the mean difference (difference between postoperative and preoperative) of the radiographic measurements, and AOFAS scores were not significantly different between two groups (p > 0.05). A total of 5 complications were observed (four in K-wire group, one in screw group). Complication rates between two groups was not statistically significant (p = 0.12). DISCUSSION Initial description of DCO did not include any fixation material. Afterwards, the procedure was modified by using single K wire in order to enhance the stability of the osteotomy. Previous studies were unable to demonstrate significant differences between K-wire fixation and cortical or Herbert type screw fixation based on clinical and radiological outcomes. Differently, in this study we compared two K-wire fixation with 3.5-mm titanium fully threaded headless cannulated screw fixation. Our results demonstrated that function and radiological measurements significantly improved after both fixation methods. Despite the increased complication rate in K-wire group, it was not statistically significant. Moreover, none of the complications was associated with unstable osteotomy, and required re-operation. CONCLUSIONS Both fixation methods provided comparable radiological and clinical outcomes with favourable results after DCO. Key words: hallux valgus, distal chevron osteotomy, Kirschner wire, headless cannulated screw, fixation method.