The Effect of Lateralization and Distalization After Grammont-Style Reverse Total Shoulder Arthroplasty

Chris Clinker; Hiroaki Ishikawa; Angela P Presson; Chong Zhang; Christopher Joyce; Peter N Chalmers; Robert Z Tashjian

doi:10.1016/j.jse.2024.03.049

The Effect of Lateralization and Distalization After Grammont-Style Reverse Total Shoulder Arthroplasty

J Shoulder Elbow Surg. 2024 May 14:S1058-2746(24)00348-3. doi: 10.1016/j.jse.2024.03.049. Online ahead of print.

Authors

Chris Clinker¹, Hiroaki Ishikawa¹, Angela P Presson², Chong Zhang², Christopher Joyce¹, Peter N Chalmers¹, Robert Z Tashjian³

Affiliations

¹ Department of Orthopaedic Surgery, University of Utah, Salt Lake City, UT, USA.
² Division of Epidemiology, Department of Medicine, University of Utah, Salt Lake City, UT, USA.
³ Department of Orthopaedic Surgery, University of Utah, Salt Lake City, UT, USA. Electronic address: Robert.Tashjian@hsc.utah.edu.

PMID: 38754540
DOI: 10.1016/j.jse.2024.03.049

Abstract

Background: The purpose of this study is to evaluate the relationship between multiple radiographic measures of lateralization and distalization and clinical outcome scores after reverse total shoulder arthroplasty (RTSA).

Methods: We retrospectively evaluated all RTSAs performed by the senior author between January 1, 2007, and November 1, 2017. We then evaluated the visual analog scale for pain (VAS pain), Simple Shoulder Test (SST), and American Shoulder and Elbow Surgeons (ASES) scores and complication and reoperation rates at a minimum of 2-year follow-up. We measured preoperative and postoperative (2-week) radiographs for the lateralization shoulder angle (LSA), the distalization shoulder angle (DSA), lateral humeral offset (LHO), and distance from glenoid to lateral aspect of the greater tuberosity (GLAGT). A multivariable analysis was performed evaluating the effect of the postoperative radiographic measurements on final patient reported outcomes (ASES scores, SST, VAS pain).

Results: The cohort included 216 shoulders from unique patients who had patient reported outcome scores available at a minimum of 2-year follow-up (average, 4.0±1.9 years) for a total follow-up rate of 70%. In the multivariable models, more lateralization (LSA) was associated with worse final ASES scores -0.52 (95% CI: -0.88 to -0.17; p=0.004), and more distalization (DSA) was associated with better final ASES scores 0.40 (95% CI: 0.11, 0.69; p=0.007). More lateralization (LSA) was associated with worse final SST scores -0.06 (95% CI: -0.11, -0.003; p=0.039). Finally, greater distalization (DSA) was associated with lower final VAS pain scores, Ratio = 0.98 (95% CI: 0.96, 1.00; p=0.021).

Conclusion: Greater distalization and less lateralization are associated with better function and less pain after Grammont-style RTSA. If utilizing a Grammont-style implant, remaining consistent with Grammont's principles of implant placement will afford better final clinical outcomes.

Keywords: DSA; LSA; RTSA; Reverse total shoulder arthroplasty; distalization; lateralization.