Rates of subacromial notching are low following reverse shoulder arthroplasty with a 135° inlay humeral component and a lateralized glenoid

Theresa Pak; Mariano E Menendez; Reuben Gobezie; Benjamin W Sears; Evan Lederman; Shoulder Arthroplasty Research Committee (ShARC) group; Brian C Werner; Patrick J Denard

doi:10.1016/j.jseint.2024.01.009

Rates of subacromial notching are low following reverse shoulder arthroplasty with a 135° inlay humeral component and a lateralized glenoid

JSES Int. 2024 Feb 10;8(3):522-527. doi: 10.1016/j.jseint.2024.01.009. eCollection 2024 May.

Authors

Theresa Pak¹, Mariano E Menendez², Reuben Gobezie³, Benjamin W Sears⁴, Evan Lederman⁵; Shoulder Arthroplasty Research Committee (ShARC) group; Brian C Werner⁶, Patrick J Denard²

Collaborators

Shoulder Arthroplasty Research Committee (ShARC) group:
Anthony Romeo, Anup Shah, Asheesh Bedi, Bradford Parsons, Brandon Erickson, Bruce Miller, Christopher O'Grady, Daniel Davis, David Lutton, Joern Steinbeck, John Tokish, Julia Lee, Justin Griffin, Kevin Farmer, Matthew Provencher, Michael Bercik, Michael Kissenberth, Patric Raiss, Peter Habermeyer, Philipp Moroder, Robert Creighton, Russell Huffman, Sam Harmsen, Tim Lenters, Tyrrell Burrus, Tyler Brolin, Albert Lin

Affiliations

¹ Center for Orthopedic Research and Education, Phoenix, AZ, USA.
² Oregon Shoulder Institute, Medford, OR, USA.
³ Cleveland Shoulder Institute, Beachwood, OH, USA.
⁴ Western Orthopaedics, Denver, CO, USA.
⁵ University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA.
⁶ University of Virginia Health System, Charlottesville, VA, USA.

Abstract

Background: Lateralization in reverse shoulder arthroplasty (RSA) decreases bony impingement and improves rotational range of motion, but has been theorized to increase the risk of subacromial notching (SaN). The purpose of this study was to evaluate the presence of SaN following RSA and its relationship with lateralization with a 135° inlay humeral component. The secondary purpose was to assess the association of SaN with functional outcomes.

Methods: A retrospective review was performed from a multicenter prospectively collected database on patients who underwent primary RSA from 2015 to 2021. All RSAs were performed with a 135° inlay humeral component. SaN was defined as bony erosion with sclerotic margins on the undersurface of the acromion on final follow-up radiographs not present preoperatively. Postoperative implant positioning (inclination, distalization, and lateralization) were evaluated on minimum 1-year postoperative radiographs. Regression analyses were performed on implant and clinical variables to assess for risk factors. A separate analysis was performed to determine the association of SaN with clinical outcomes.

Results: SaN was identified in 13 out of 442 shoulders (2.9%). Age, sex, body mass index, smoking status, diabetes mellitus, arm dominance had no relationship with SaN. Neither glenoid sided lateralization nor humeral offset were associated with SaN risk. Other implant characteristics such as distalization, glenosphere size, and postoperative inclination did not influence SaN risk. The presence of SaN did not affect patient-reported outcomes (American Shoulder and Elbow Surgeons: P = .357, Visual Analog Scale: P = .210) or range of motion.

Conclusion: The rate of SaN is low and not associated with glenoid or humeral prosthetic lateralization when using a 135° inlay humeral component. When SaN occurs, it is not associated with functional outcomes or range of motion at short-term follow-up.

Keywords: Abduction impingement; Inlay; Lateralization; Outcomes; Reverse shoulder arthroplasty; Subacromial notching.