Investigating the surgical outcomes transitioning from a traditional grammont-style valgus-medialized reverse shoulder arthroplasty to a varus lateralized reverse shoulder implant
Year: 2025
Type: article
Study design: Observational Study
Abstract: Background Reverse total shoulder arthroplasty (rTSA) has undergone significant evolution since its inception, particularly in implant design and surgical techniques. One implant design that has changed dramatically over the years is the humeral neck–shaft angle (NSA), which has seen a shift toward a smaller angle since the original Grammont design. This study aims to compare pain and functional outcomes during the transition period from valgus to varus humeral stem implants in rTSA, as well as provide commentary on the technical challenges encountered. Methods A retrospective review was conducted on the last 50 patients who underwent rTSA with a traditional Grammont style 150° NSA implant and the first 50 patients with a 135° NSA implant by a single surgeon between January 2019 and December 2022. This study aims to investigate the transition between implant systems by assessing patient outcomes including active forward flexion, active external rotation (AER), visual analog scale (VAS) pain scores, American Shoulder and Elbow Surgeons (ASES) scores, and complication rates such as readmissions and revisions at various postoperative time points. Statistical analyses employed linear mixed-effects models adjusted for demographic and clinical covariates. Results The study analyzed 100 patients, the last 50 patients who underwent Grammont Style medialized valgus (150° NSA) rTSA to the first 50 patients implanted with a lateralized varus (135° NSA) rTSA, with a mean follow-up of 2.6 years. Compared to the medialized valgus implant, patients with the lateralized varus implant demonstrated significantly greater AER starting at 2 months (8° difference, P = .032) and persisting at 1 year (8° difference, P = .032). Otherwise, VAS pain scores, ASES scores, and complications rates did not differ significantly at any time point between implant types. Conclusions While initial postoperative improvements in AER favors the 135° NSA system compared to the 150° NSA system, both implant types yielded comparable outcomes in range of motion, VAS pain, ASES scores, and complications. In spite of this, there are multiple technical points and important differences between the 2 design philosophies that are consequential for surgeons to personalize patient treatment plans, minimize complications, optimize shoulder biomechanics, and refine outcomes.
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $1,370
Funder: Loyola University Chicago
OpenAlex ID: W4416426523