# Lower average cortical bone thickness predicts cemented fixation in short-stem reverse shoulder arthroplasty

## TL;DR

This study found that lower average cortical bone thickness is a key factor in deciding to use cemented fixation during a specific type of shoulder surgery.

## Contribution

The study identifies lower average cortical bone thickness as the strongest predictor for cemented fixation in short-stem reverse shoulder arthroplasty.

## Key findings

- Cemented fixation was more common in older patients and females with lower cortical bone thickness.
- Lower average cortical bone thickness (CBTavg) was the strongest independent predictor for cemented fixation.
- Preoperative CBTavg measurements could improve surgical decision-making for fixation strategy.

## Abstract

This study aimed to identify radiographic and demographic predictors influencing the intraoperative decision for cemented versus cementless humeral fixation in patients ≤ 80 years undergoing short-stem reverse shoulder arthroplasty (RSA).

A retrospective analysis was conducted on RSA cases between 02/2019 and 10/2024. Patients ≤ 80 years were stratified into Group A (cementless fixation; n = 209) or Group B (cemented fixation; n = 58) based on intraoperative assessment of trial stem stability and bone quality. Preoperative variables included age, sex, body mass index (BMI), American Society of Anesthesiologists score (ASA), diagnosis, and radiographic parameters such as cortical bone thickness gauge (CBTg), average cortical thickness (CBTavg), acromiohumeral distance (AHD), and Hamada and Walch classifications. Multivariate logistic regression including age, sex, CBTavg, CBTg, and diagnosis was performed to identify independent predictors of cemented fixation.

Patients in the cemented group were significantly older (74.0 ± 4.2 vs. 70.0 ± 6.1 years; p < 0.05) and more often female (81% vs. 61%; p < 0.05). Cortical bone measurements were significantly lower in the cemented group (CBTg: 0.25 ± 0.06 vs. 0.27 ± 0.06; CBTavg: 5.15 mm ± 1.23 mm vs. 6.42 mm ± 1.43 mm; both p < 0.05). Multivariate analysis identified increasing age (OR: 1.1; p < 0.05), female sex (OR: 2.8; p < 0.05), and reduced CBTavg (OR: 0.6; p < 0.05) as independent predictors of cemented fixation. Other variables such as BMI, ASA score, AHD, and CBTg did not show significant associations with fixation type.

Among all evaluated factors, lower CBTavg was the strongest independent predictor for the use of cemented humeral fixation in short-stem RSA. Its integration into preoperative planning may assist surgical decision-making and improve consistency in fixation strategy.

Level IV; retrospective case series.

The online version contains supplementary material available at 10.1186/s13018-025-06606-1.