LAUSR

Introduction: We aimed to perform a systematic review to identify factors that may lead to poorer outcomes in arthroscopic surgery for posterior shoulder instability. Methods: We searched MEDLINE, Embase and the Cochrane Database of Systematic Reviews for 757 unique articles. We eventually included 22 articles. Data were analysed using Review Manager 5.3. Results: The presence of chondral damage was associated with poorer outcomes as reflected in a higher post-operative Quick Disabilities of theArm, Shoulder and Hand score (mean difference (MD) = 17.1; 95% confidence interval (CI) = 2.82–31.4; p = 0.02), higher WesternOntario Shoulder Instability (WOSI) index (MD = 468.0; 95% CI = 136.5–799.5; p = 0.006), lower Simple Shoulder Test score (MD = −2.40; 95% CI = −4.34 to −0.46; p = 0.02) and a lower Single Assessment Numeric Evaluation score (MD = −15.4; 95% CI = −30.6 to −0.23; p = 0.05). The presence of previous shoulder surgery was associated with poorer outcomes as depicted by a lower American Shoulder and Elbow Society (ASES) score (MD = −93.1; 95% CI = −96.9 to −89.3; p < 0.0001). The availability of workers’ compensation was associated with poorer outcomes as revealed by a lower rate of return to work (odds ratio (OR) = 0.02; 95% CI = 0.00–0.20; p = 0.0008). The presence of additional procedures while performing surgery for posterior shoulder instability was associated with poorer outcomes as reflected by lower ASES scores (MD = −6.70; 95% CI = −8.64 to −4.76; p < 0.0001), higher WOSI index (MD = 63.4; 95% CI = 33.0–93.8; p < 0.0001), lower University of California at Los Angeles (UCLA) scores (MD = −2.30; 95% CI = −2.81 to −1.79; p < 0.0001), higher pain scores (MD = 0.72; 95% CI = 0.39–1.05; p < 0.0001) and higher post-operative instability (MD = 0.80; 95% CI = 0.57–1.03; p < 0.0001). Conclusion: The presence of chondral damage, previous shoulder surgery, concomitant surgery and workman’s compensation was associated with poorer outcomes for arthroscopic repair of posterior shoulder instability. Further studies should be done to further validate these factors.