Background This systematic review aims to assess the effectiveness between exclusive polyethylene (PE) glenoid implants and metal back (MB) implants in anatomical total shoulder arthroplasty. Methods We have systematically reviewed the literature and include full-text randomized clinical trials (RCTs) comparing PE (keeled and pegged) versus MB implants, available in PubMed, Scopus, Embase, Cochrane CENTRAL, LILACS, Web of Science, WHO ICTRP, Clinical trials. Grey literature was also hand searched assessed . Results Eight RCTs were included, with 323 patients and 338 shoulders, with follow-up from six weeks to ten years. Shoulder function through the Constant-Murley score, range of motion and pain through the Visual Analogue Scale, were important outcomes to access the PE components that showed no difference; meanwhile, there was a reduction in radiolucency lines (RL) up to grade two around 50% and 12.4% for complications and surgery revisions in favour of the peg over the keel. Compared to MB, there was 25% more RL around PE, however function and complication rates were equivalent. Discussion The PE component in anatomical total shoulder arthroplasty shows more RL compared to MB, especially around the keel design . Despite this, there were no significant differences in complications or revision surgery between both groups.
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