Screw Only Fixation vs Plate Fixation For 1st MTPJ Arthrodesis: A Comparative Retrospective Study

Abstract

Category: Midfoot/Forefoot; Other Introduction/Purpose: First metatarsolphalangeal joint (MTPJ) arthrodesis is a commonly performed surgical procedure for end- stage arthritis. Various fixation techniques have been described. The most commonly used are screw-only fixation (either crossed or parallel) or plate fixation (with or without independent lag-screws). A recent systematic review reported that union rates for screw fixation were lower compared to plate constructs. The aim of this study was to compare union rates, complication rates and functional outcomes between screw-only fixation and plate fixation in a recent cohort of patients undergoing first MTPJ arthrodesis at a tertiary foot ankle orthopaedic institution. Methods: This was a retrospective cohort study. After institutional review board approval, a database search was conducted to identify patients who underwent primary first MTPJ arthrodesis between 2015 and 2022. All patients had a dorsal approach, preparation of joint surfaces with cup and cone reamers and fixation with either crossed cannulated screws or a dorsal pre- contoured locking plate (with or without an independent lag-screw). Demographic, operative (fixation type) and outcome data was collected. The primary outcome was the incidence of arthrodesis at 6 months postoperatively. Secondary outcomes included complications at 6 months postoperatively and change in functional outcome scores from preoperatively to 6 months postoperatively as assessed by the Functional Ankle Ability Measure (FAAM) and Visual Analog Pain scores (VAS). Statistical analyses included descriptive statistics as well as univariable and multivariable analyses to determine if one fixation method was associated with a higher incidence of arthrodesis. Results: There were 108 patients identified, 54 in the screw-only group (mean age 62.9 years, 79.6% female, mean body-mass index (BMI) 28.6 kg/m2) and 54 in the plate-fixation group (mean age 63.2 years, 81.5% female, mean BMI 30.0kg/m2). Arthrodesis at 6 months in the screw-only group occurred in 52 of 54 patients (96.3%) and in 50 of 54 patients (92.6%) in the plate-fixation group, p=0.68. Fixation type was not a predictor of non-union on multivariable analysis. The complication rate was 11.1% (n=6) in screw-only patients (four hardware removals, two non-unions) and 14.8% (n=8) in plate-fixation patients (four non-unions, two hardware removals, two wound infections), p=0.57. Both groups reported increases in VAS and FAAM scores at 6 months from baseline, with no significant between-group differences. Conclusion: The arthrodesis rate for screw-only fixation was higher than patients receiving plate-fixation, however, this difference did not reach statistical significance. Similar complication rates were observed in each group. These results provide evidence for the safety and efficacy of screw-only fixation constructs, however, further adequately powered prospective studies are required. Future studies should also include a cost effectiveness analysis and a comparison of radiation exposure and operative time between groups to determine the optimal fixation method for patients undergoing this procedure.