# Do uncemented humeral components perform better than cemented humeral components in reverse total shoulder arthroplasty for acute proximal humerus fracture? A New Zealand Joint Registry study

## TL;DR

A study using New Zealand Joint Registry data found no significant difference in implant survival or patient outcomes between cemented and uncemented humeral components in reverse shoulder arthroplasty for proximal humerus fractures.

## Contribution

This study provides the first large-scale registry comparison of cemented versus uncemented humeral components in reverse total shoulder arthroplasty for acute proximal humerus fractures.

## Key findings

- Revision rates were 0.64 per 100 component-years for cemented and 0.36 for uncemented stems, with no significant difference.
- Oxford Shoulder Scores improved over time, with uncemented stems showing slightly better 5-year outcomes, though not clinically significant.
- Both cemented and uncemented stems are acceptable for treating acute proximal humerus fractures.

## Abstract

Reverse total shoulder arthroplasty (rTSA) is increasingly used in unreconstructible and comminuted proximal humerus fractures. There is ambiguity as to whether uncemented or cemented humeral components (stems) have better survival and patient-reported outcome measures in this context. The aim of this study was to compare implant survival, risk of revision, reason for revision, and functional outcomes between cemented and uncemented stems for rTSA performed for acute proximal humerus fractures.

Prospectively collected data from the New Zealand Joint Registry, a national database with capture >95%, were used to compare the survival rates and Oxford Shoulder Scores of rTSA performed for trauma (trauma rTSA) using cemented or uncemented stems between January 2002 and December 2024. Reason for revision and patient demographics were recorded. Revision rates (rates per 100 observed component years) and functional outcomes (Oxford Shoulder Score at 6-month and 5-year follow-up) were compared using a multivariate Cox proportional hazards regression model and adjusted by age, sex, American Society of Anesthesiologists class, and surgeon volume of rTSA per year.

Over the 22-year study period, 843 rTSA procedures were performed for acute proximal humeral fracture representing 4,668 component years. Of these trauma rTSA procedures, 326 utilized a cemented stem (cemented trauma rTSA) and 517 utilized an uncemented stem (uncemented trauma rTSA). The number of revisions per 100 component-years for cemented trauma rTSA was 0.64, compared to 0.36 for uncemented trauma rTSA. This difference was not statistically significant (P = .122). Mean Oxford Scores 6 months postoperatively were 30.4 for cemented trauma rTSA and 31.3 for uncemented trauma rTSA (P = .365). Mean Oxford Scores 5 years postoperatively were 36.2 for cemented trauma rTSA and 39.5 and for uncemented trauma rTSA (P = .049), although this is less than the minimally clinically important difference.

In the context of increasing use of rTSA for acute proximal humerus fractures, revision rates and patient-reported outcomes are similar between cemented and uncemented humeral stems. Uncemented humeral components are therefore an acceptable first-line treatment for proximal humerus fractures in appropriate patients.