Review Article

Stress shielding in stemmed reverse shoulder arthroplasty: an updated review

¹ Department of Orthopaedic Surgery, St. Luke’s Hospital, Panorama-Thessaloniki, 55236, Greece
² Orthopaedics Surgery and Sports Medicine Department, FIFA Medical Center of Excellence, Croix-Rousse Hospital, Lyon University Hospital, Lyon, 69004, France
³ Ramsay Santé, Hôpital Privé Jean Mermoz, Centre Orthopédique Santy, 24 avenue Paul Santy, Lyon 69008, France
⁴ Orthopaedics Department, Bioclinic, 11524 Athens, Greece
⁵ Interuniversity Laboratory of Biology of Mobility, LIBM, EA 7424, Claude Bernard Lyon 1 University, Lyon, 69008, France
⁶ Univ Lyon, Claude Bernard Lyon 1 University, IFSTTAR, LBMC UMR_T9406, Lyon, 69622, France

^* Corresponding author: vasigiova@gmail.com

Received: 8 July 2024
Accepted: 26 July 2024

Abstract

Background: Reverse shoulder arthroplasty (RSA) is popular for the treatment of degenerative glenohumeral joint disease. Bone remodeling around the humeral stem related to stress shielding (SS) has been described. This review focuses on the specific radiological characteristics, risk factors, and clinical consequences of SS in RSA. Methods: A meticulous review was conducted of articles published between 2013 and 2023. Data on the definition, risk factors, and clinical impact of stress shielding were recorded. Results: Twenty-eight studies describing 2691 patients who had undergone RSA were included. The mean age of patients ranged from 63 to 80 years with mean follow-up periods of 12 months to 9.6 years. The prevalence of SS reached up to 39% at a 2-year follow-up. Females and elderly are typically at higher risk due to osteopenia. SS was more frequent with the use of long stems(>100 mm) compared to short stems(<100 mm). Stem design, onlay or inlay, and neck-shaft-angle did not influence SS. Frontal misalignment and a high filling ratio are riskfactors for SS. Biological factors also contribute to SS, associated with scapular notching. No correlation was found between SS and clinical outcomes. Conclusions: SS is common in patients with cementless implants after RSA, especially in female and elderly patients. It can be limited by implanting stems with a low diaphyseal filling-ratio, in correct coronal alignment. Risk factors for polyethylene debris, primarily scapular notching, should be avoided. The authors found no clinical consequences of stress shielding, but longer-term follow-up studies are required to confirm these findings.