Outcomes of Augmented versus Standard Baseplates in Reverse Shoulder Arthroplasty

Background: Glenoid bone loss presents a complex challenge in the management of patients with glenohumeral osteoarthritis (GHOA) undergoing Reverse Shoulder Arthroplasty (RSA). Eccentric reaming and bone grafting have been utilized to address this issue but are associated with their own set of challenges. This study explores the effectiveness of augmented glenoid baseplate RSA in addressing glenoid bone loss. Thus, the primary aim of this study was to compare the patient-reported outcomes (PROs) of patients undergoing RSA with augmented baseplates versus standard baseplates. Secondary outcomes included shoulder function, postoperative complications, and revisions.

Methods: A retrospective review of patients treated with primary RSA by a single fellowship-trained surgeon was performed. All patients received a standard reverse shoulder arthroplasty implant with the same system and long humeral stem (Exactech Equinoxe Reverse System (Exactech, Inc., Gainesville, FL, USA). Patients were separated into a standard baseplate group (SG) and an augmented baseplate group (AG), which was further divided by the type of augment into three subgroups (superior, posterior, superior/posterior). Demographic variables, range of motion (ROM), PROs and pain scores were collected preoperatively and latest follow-up visit, in addition to postoperative complications and revision rates. PROs included American Shoulder and Elbow Surgeons (ASES), and others such as Simple Shoulder Test (SST), University of California Los Angeles (UCLA) Shoulder, Constant Shoulder, and Shoulder Pain and Disability Index (SPADI) scores. For each variable, the augmented groups were compared to the SG and statistical analysis was performed.

Results: A total of 447 patients (SG = 279 patients, AG = 168 patients) were included in this analysis. Compared to the SG, there were significantly more males in the AG (p<0.01) and fewer patients with the diagnosis of RCT (p=0.04). At a mean follow-up of 26 months, the AG and each of the augmented subgroups performed as well, or better, than the SG on all functional and PROs. No significant difference was found in rates of complications, revisions, humeral radiolucent lines, glenoid loosening, or scapular notching.

Conclusions: Augmented baseplates can be a good option for the treatment of severely deformed glenoids by rTSA. Augmented baseplates appear to perform as well or better than standard baseplates in rTSA with no significant difference in rates of complications. Each of the augmented subgroups achieved excellent clinical outcomes and range-of-motion measures at early follow-up. This study adds to the growing body of evidence that augmented baseplates are durable implant options and may play a role in addressing glenoid bone loss in rTSA, offering better patient outcomes and expanding the options available to orthopedic surgeons.