Reverse total shoulder arthroplasty within 6 weeks of proximal humerus fracture is associated with the lowest risk of revision

Background: Reverse total shoulder arthroplasty (RTSA) has become an increasingly popular treatment strategy in the management of complex proximal humeral fractures (PHFs). However, no definitive consensus has been reached regarding the optimal surgical timing of RTSA following PHF, particularly considering nonoperative management is often a viable option. Therefore, the aim of this study was (1) to identify optimal timing intervals that maximize the likelihood of revision following RTSA and (2) to determine differences in revision etiologies using the identified timing intervals. Methods: A retrospective cohort analysis of patients undergoing PHF-indicated RTSA from 2010 to 2021 was conducted using a national administrative claims database. Stratum-specific likelihood ratio (SSLR) analysis was conducted to determine data-driven timing strata between PHF and RTSA that maximized the likelihood of revision surgery within 2 years of RTSA. To control for confounders, multivariable regression analysis was conducted to confirm the identified data-driven strata's association with 2-year revision rates as well as compare the likelihood of various indications for revision including mechanical loosening, dislocation, periprosthetic joint infection (PJI), and periprosthetic fracture (PPF). Results: In total, 11,707 patients undergoing TSA following PHF were included in this study. SSLR analysis identified 2 timing categories: 0-6 weeks and 7-52 weeks from the time of PHF to TSA surgery. Relative to the 0-6-week cohort, the 7-52-week cohort was more likely to undergo revision surgery within 2 years (OR 1.93, P < .001). Moreover, the 7-52-week cohort had significantly higher odds of revision indicated for dislocation (OR 2.24, P < .001), mechanical loosening (OR 1.71, P < .001), PJI (OR 1.74, P < .001), and PPF (OR 1.96, P < .001). Conclusions: Using SSLR, we were successful in identifying 2 data-driven timing strata between PHF and RTSA that maximized the likelihood of 2-year revision surgery. As it can be difficult to determine whether RTSA or nonoperative management is initially more appropriate, considering the results of this study, an early trial of 4-6 weeks of nonoperative management may be appropriate without altering the risks associated with RTSA.