Metal vs non-metal fixation methods for patellar fractures: A systematic review and meta-analysis of clinical and radiographic outcomes.

Introduction: This paper aims to systematically review and meta-analyse the available evidence regarding the clinical and radiographic outcomes of non-metal fixation methods in treating patellar fractures compared to a control metal fixation group, in the hopes of bringing insight into their effectiveness. Methods: Two investigators systematically reviewed studies across 9 English or Mandarin electronic databases - Cochrane Library, EMBASE, Google Scholar, Medline, PubMed, Scopus, Web of Science, CNKI and Wanfang Data, in adherence to PRISMA guidelines. The inclusion criteria for study selection were: English or Mandarin comparative studies that evaluated clinical (Patient Reported Outcome Measures, incidence of reoperations and postoperative complications) or radiographic (time to union and incidence of secondary loss of reduction) outcomes of metal and non-metal fixation methods for patellar fractures. From an initial pool of 1269 studies, 19 studies involving 1612 patients were included in the meta-analysis after full-text evaluation and accounting for exclusion criteria. Results: Clinically, the reduction in reoperations (OR = 0.22, 95% CI [0.10, 0.51], P = 0.0003), direct (OR = 0.17, 95% CI [0.08, 0.33], P < 0.00001) and indirect (OR = 0.50, 95% CI [0.27, 0.93], P = 0.03) implant-related postoperative complications were significantly in favor of non-metal fixation. Radiographically, the decrease in time to union (SMD = -0.79, 95% CI [-1.11, -0.47], P < 0.00001) in the non-metal group compared to the metal group was also significant. The remaining results were comparable. Conclusion: This meta-analysis suggests that non-metallic internal fixation had similar if not superior outcomes to their metallic counterparts, with fewer implant-related complications and improved postoperative recovery. Given the higher re-operation rates associated with metallic fixation, non-metallic methods may be preferable from economic and safety perspectives. Nevertheless, more homogenous studies with standardised fracture configurations and treatment modalities are needed before declaring non-metallic fixation as the gold standard for patellar fractures.