Reverse Shoulder Arthroplasty Humeral Lateralisation: A Systematic Review.

Govind Dhillon,Madeline Warren,Harpal S Uppal,Angelos Assiotis,Adam Rumian

doi:10.7759/cureus.19845

Abstract

Different studies on reverse shoulder arthroplasty (RSA) have proposed changes to the humeral design to lateralise the humeral centre of rotation (COR), with humeral inclination to 135 or 145 from 155 degrees or to switch to onlay humeral trays from inlay design; with both having also been used in combination. There have been many studies and systematic reviews to show the difference in outcomes and complications to the variations in glenoid design but to date, there have been no systematic studies to compare different humeral inclinations for RSA implants.Searches using keywords were used in common medical search engines in a systematic fashion. The article was reviewed for the class of evidence and bias, summarised and compared in meta-analysis. Inclusion criteria included studies on adults with RSA that compared lateralised humeral implants to medialised.The search produced 349 articles; of these, we identified nine studies that met the inclusion criteria. Our review identified a total of 562 patients who had been included in studies directly comparing lateralised humerus to a more medial design. Meta-analysis showed a significantly reduced risk of scapular notching in lateralised humerus compared to the standard medialised component. The external rotation range of motion in the lateralised group was statistically significant.The improvement in scapular notching and gain in the range of motion without any apparent downside in the form of reduced patient-reported outcome measures or complications suggest a lateralised humeral component is superior to the more medialised design in RSA. A large RCT with a longer-term follow-up is needed to confirm whether there is clinically significant benefit from the lateralisation of the humerus.

Highlights

BackgroundThe glenohumeral joint is prone to many disabling conditions, including rotator cuff tears, rotator cuff tear arthropathy, shoulder osteoarthritis, glenoid bone loss, and proximal humerus fracture [1-3]
The number of reverse shoulder arthroplasty procedures performed in the UK has been increasing steadily since National Joint Registry (NJR) first began recording in 2012 [4]
The massive increase in the use of the Reverse shoulder arthroplasty (RSA) over the last three decades has been driven by these innovations, such that the centre of rotation of glenoid components in most modern RSA is medialised compared to the anatomical COR

Summary

Introduction

BackgroundThe glenohumeral joint is prone to many disabling conditions, including rotator cuff tears, rotator cuff tear arthropathy, shoulder osteoarthritis, glenoid bone loss, and proximal humerus fracture [1-3]. Reverse shoulder arthroplasty (RSA) is a frequently used treatment for these conditions and generally gives good clinical outcomes where conservative measures may fail. The number of reverse shoulder arthroplasty procedures performed in the UK has been increasing steadily since National Joint Registry (NJR) first began recording in 2012 [4]. Designs aimed to mimic the anatomical centre of rotation (COR) [5]. The design of RSA was popularised by the Grammont design that medialises both the humerus and the glenoid [6]. The medialised designs have many theoretical and clinical advantages over earlier generation designs. The massive increase in the use of the RSA over the last three decades has been driven by these innovations, such that the centre of rotation of glenoid components in most modern RSA is medialised compared to the anatomical COR

Objectives

Methods

Results

Discussion

Conclusion