Impact of age on functional outcome after reverse shoulder arthroplasty performed for proximal humerus fractures or their sequelae

The use of reverse shoulder arthroplasty (RSA) to treat displaced, unstable 3- and 4-part proximal humerus fractures (PHFs) has traditionally been reserved for patients over 70 years old. However, recent data suggest that nearly one third of all patients treated with RSA for PHF are between 55-69 years old. The purpose of this study was to compare outcomes for patients younger than 70 versus patients older than 70 years of age treated with RSA for a PHF or fracture sequelae. All patients who underwent primary RSA for acute PHF or fracture sequelae (nonunion, malunion) between 2004 and 2016 were identified. A retrospective cohort study was performed comparing outcomes for patients younger than 70 versus patients older than 70. Bivariate and survival analyses were performed to evaluate for differences in complications, functional outcomes, and implant survival. A total of 115 patients were identified, including 39 patients in the young group and 76 patients in the older group. 40 patients (43.5%) returned functional outcomes surveys at an average of 5.51 years (range 3.04-11.0). There were no significant differences in complications, reoperation, implant survival, range of motion, DASH (27.9 vs 23.8, p=0.46), PROMIS (43.3 vs 43.6, p=0.93), or EQ5D (0.75 vs 0.80, p=0.36) scores between the two age cohorts. At a minimum of 3 years after RSA for a complex PHF or fracture sequelae, we found no significant difference in complications, reoperation rates, or functional outcomes between younger patients with an average age of 64 years and older patients with an average age of 78 years. To our knowledge, this is the first study to specifically examine the impact of age on outcome after RSA for the treatment of a proximal humerus fracture. These findings indicate that functional outcomes are acceptable to patients younger than 70 in the short term, but more studies are needed. Patients should be counseled that the long-term durability of RSA performed for fracture in young, active patients remains unknown.