SMR TT Augmented 360 baseplates, how do they compare to standard baseplates in reverse shoulder arthroplasty: minimum 2 years clinical and radiographic follow-up.

Abstract

Background: Reverse Total Shoulder Arthroplasty (rTSA) is a popular surgical option for end stage arthritis, rotator cuff arthropathy or proximal humerus fractures. The treatment of patients with glenoid bone loss and deformity, however, remains challenging. Modern implant systems now have the option of wedge-shaped augmented baseplates to supplement deficient glenoid bone and omit the need for excessive glenoid reaming or the use of bone graft.This study set out to establish if the new augmented base plates were clinically and radiologically comparable to standard baseplates.

Methods: A retrospective review of prospectively collected data was conducted on all patients who received the SMR 360 TT Augmented baseplate (Lima Corporate, Udine, Italy) between January 2020 and March 2022. All data were collected as part of the hospital prospective database from which a comparative sample of patients who received a standard baseplate was obtained. Minimum follow-up period was 2 years. Preoperative clinical information was recorded using pain score (1-5), Oxford Shoulder Score (OSS), American Shoulder and Elbow Surgeons (ASES) score, and Range of motion. The same clinical scores were collected at two-year follow-up with radiological assessments.

Results: A total of 104 patients were included in this study, with 52 in the Augmented group and 52 in the Standard Group. At minimum two years follow-up there were no statistically significant differences between the two groups in OSS, pain score or range of motion at two years. Post operative ASES scores were 73 ± 22 in the augment group and 82 ± 15 in the standard baseplate group; this difference was statistically - but not clinically - significant. There was a statistically significant difference in the size of overhang with the Augmented Group having average glenoid overhang of 5.0 ± 1.9mm, while the Standard Group had an average of 6.5 ± 1.8mm. There was no other statistically or clinically significant difference in any other radiological outcome DISCUSSION: In both groups, it was possible to achieve a well-fixed stable rTSA with improved functional and radiological outcomes at two-year follow-up. Augmented baseplates were not clinically inferior to standard baseplates across any measure. This study demonstrates that augmented baseplates appear to be a safe alternative to other techniques such as eccentric reaming or Boney Increased Offset Reverse Shoulder Arthroplasty (BIO-RSA) with reliable patient outcomes.