Does lateralisation and distalisation affect revision rates and patient experience in primary stemmed reverse shoulder arthroplasty?

Background: This study examined the association between distalisation and lateralisation of implant components and revision outcomes and patient-reported outcome measures (PROMs) following primary total stemmed reverse shoulder arthroplasty (rTSA) using data from a national arthroplasty registry. Materials and Methods:All primary total stemmed modular rTSA procedures (excluding custom implants) recorded between 1 January 2015 and 31 December 2023 were identified.A total of 25,837 primary rTSA procedures were included.Procedures were classified into six construct groups based on humeral and glenoid component features associated with distalisation and/or lateralisation.Kaplan-Meier methods were used to estimate cumulative percent revision (CPR).Cox proportional hazards models estimated adjusted hazard ratios (HRs), controlling for age, sex, ASA score, body mass index, primary diagnosis, glenosphere size, and glenoid morphology.Subgroup analyses were performed for inlay and onlay humeral configurations.PROMs collected from November 2018 were analysed in a subset of patients.Results: Constructs incorporating humeral distalisation demonstrated higher revision rates beyond 1.5 years compared with standard components (p = 0.002).Augmented glenoid baseplates were associated with lower early revision rates within three months (p = 0.002).Onlay designs incorporating distalisation and/or lateralisation showed increased revision risk during specific postoperative periods.Instability or dislocation was the most common indication for revision, while infection was more frequent in constructs combining distalisation and lateralisation.All groups demonstrated significant improvements in EQ-VAS and Oxford Shoulder Score at six months.J o u r n a l P r e -p r o o f Conclusion: Humeral distalisation was associated with higher medium-term revision rates despite early improvements in PROMs, highlighting trade-offs in implant selection Level of Evidence: Level III; Retrospective Cohort Comparison using Registry Data;