Sarcopenia of the deltoid as an indicator of outcome following reverse total shoulder arthroplasty: a systematic review and meta-analysis
Bibliographic record
Abstract
<h2>Abstract</h2><h3>Background</h3> Reverse total shoulder arthroplasty (rTSA) is increasingly utilized for managing rotator cuff tear arthropathy, shoulder osteoarthritis, and proximal humerus fractures. The deltoid generates the key mechanical force after rTSA. The functional success of a rTSA is dependent on the status of the deltoid muscle. Sarcopenia, defined as age-related loss of skeletal muscle mass and function, has been linked to poor outcomes in various surgical contexts. This systematic review investigates the impact of radiologically measured deltoid sarcopenia on functional and patient-reported outcomes following rTSA. <h3>Methods</h3> A systematic search of MEDLINE, PUBMED, and SCOPUS was conducted to identify studies assessing deltoid sarcopenia via radiological imaging in rTSA patients. Inclusion criteria included studies reporting both radiological measurements of the deltoid and functional or patient-reported outcome measures (PROMs). Risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) and the Methodological Index for Nonrandomized Studies (MINORS). <h3>Results</h3> Fourteen studies comprising 1,681 shoulders were included. Studies ranged from 2010 to 2024. Eight studies used a prosthesis based on the Grammont concept design, four studies used a reduced neck shaft angle of 135° (NSA), and two studies the prothesis was not stated. Radiological modalities included MRI, CT, ultrasound, and X-ray, with deltoid cross-sectional area (CSA) being the most frequently measured parameter. Meta-analysis revealed a weak, non-significant association between preoperative deltoid CSA and postoperative Constant-Murley Score (CMS) (r = 0.12, p=0.702) but a moderate positive association with postoperative muscle strength (r = 0.38, p < 0.001). Deltoid sarcopenia, particularly fatty infiltration and reduced muscle Caliber, was associated with poorer outcomes, including lower CMS, reduced strength, and diminished PROMs. <h3>Conclusion</h3> Radiological evidence of deltoid sarcopenia correlates with suboptimal functional and patient-reported outcomes after rTSA, the pooled effects of which are not statistically significant. However, methodological heterogeneity and inconsistent use of sarcopenia metrics limit the generalizability of these findings. Standardized imaging protocols and sarcopenia definitions are essential for improving predictive accuracy and guiding clinical decision-making.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.006 | 0.004 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".