Study Question
How common is baseplate loosening, and which patients are most at risk?
The Story
In the early days of reverse shoulder arthroplasty, baseplate failure was a major concern. Schell and colleagues analyzed the clinical outcomes of 7,162 patients using a modern reverse shoulder arthroplasty (rTSA) design to better quantify the real incidence of this difficult complication. They wanted to know if the fixation problem has truly been solved and to identify which patients may still be prone to this complication.
Key Findings
- Strong fixation: The overall rate of rTSA glenoid baseplate loosening was remarkably low – just 0.74% (53 of 7,162 primary rTSA). Aseptic loosening rates were similar for gender, with female patients having a 0.7% rate (31 of 4380) and male patients having a 0.8% rate (22 of 2719).
- Patient risk factors: Patients with rheumatoid arthritis (RA), diabetes and Walch B3 glenoids had a significantly higher risk for aseptic glenoid loosening.
- Implant risk factors: Patients receiving posterior/superior augmented glenoid baseplates and expanded/lateralized glenospheres had a significantly higher risk for aseptic glenoid loosening.
Higher Combined Risk Factors
| Risk Factors | Loosening Rate | Odds Ratio (OR) |
|---|---|---|
| Superior or Posterior-Superior Augment in RA Patient | 16.7% | 22.8 |
| Expanded Offset Glenosphere + Superior or Posterior-Superior Augment | 7.5% | 9.19 |
| Walch B2 or B3 + Superior or Posterior-Superior Augment | 5.6% | 6.85 |
| Diabetes + Superior or Posterior-Superior Augment | 5.1% | 6.39 |
Clinical Context
Modern rTSA designs have made aseptic glenoid loosening a relatively rare occurrence. However, some rTSA patients are more at-risk patients, including those with poorer bone quality (e.g. RA) and/or severe deformity (e.g. Walch B3 and superior/posterior defects). Surgeons should be extra diligent when achieving fixation in these scenarios.
Limitations
These findings of this study are limited because only 3,127 of 7,162 rTSA patients had two-year minimum follow-up at the time of the analysis.
Reference for this study: Schell LE, et al. Aseptic glenoid baseplate loosening after reverse total shoulder arthroplasty with a single prosthesis. J Shoulder Elbow Surg. 2023;32(8):1584-1593. doi: 10.1016/j.jse.2023.01.010.
High-Risk Profiles and Variables
Higher risk of aseptic loosening with Walch Type B3 glenoids
Rheumatoid Arthritis
Odds Ratio
Diabetes
Odds Ratio
