Predictive Factors Influencing Internal Rotation Following Reverse Total Shoulder Arthroplasty

Abstract

Introduction Reverse total shoulder arthroplasty (RSA) is increasingly utilized as a treatment modality for various pathologies. The purpose of this review is to identify preoperative risk factors associated with loss of IR following RSA. Methods A systematic review was conducted using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Ovid MEDLINE, OVID Embase and Scopus were queried. The inclusion criteria were: English language, minimum one-year follow-up postoperatively, study published after 2012, minimum of ten patients in a series, surgery was RSA for any indication, IR is explicitly reported. The exclusion criteria were: full text was unavailable, unable to be translated to English, follow-up < one year, case reports or series of less than ten cases, review articles, tendon transfers were performed at the time of surgery, the procedure performed was not RSA, and the range of motion in IR was not reported. Results The search yielded 3,792 titles, and 1,497 duplicate records were removed before screening. Ultimately, 16 studies met inclusion criteria with a total of 5124 patients that underwent RSA. Three studies found that poor preoperative functional IR served as a significant risk factor for poor postoperative IR. Eight studies addressed the impact of subscapularis with four reporting no difference in IR based on subscapularis repair, and four reporting significant improvements with subscapularis repair. Additionally, two studies reported that BMI negatively affected IR, while two showed it had no impact. Preoperative opioid use was found to negatively affect IR. Other studies showed that glenoid retroversion, component lateralization and individualized component positioning affected postoperative IR. Discussion/Conclusion: This study found that preoperative IR, individualized implant version, preoperative opioid use, increased glenoid lateralization were all found to have a significant impact on IR following RSA. Studies that analyzed the impact of subscapularis repair and BMI reported conflicting results.