BIOMECHANICAL EVALUATION OF PROXIMAL HUMERAL FRACTURE FIXATION SUPPLEMENTED WITH CALCIUM PHOSPHATE CEMENT
Bibliographic record
Abstract
BACKGROUND: Proximal humeral fractures are common injuries, and numerous surgical methods have been described for their treatment. The biomechanical characteristics of various internal fixation devices that are used to treat these fractures have not been extensively studied, nor has the potential beneficial effect of calcium phosphate cement supplementation. METHODS: We used a cadaveric three-part proximal humeral osteotomy model to perform a biomechanical evaluation of three types of internal fixation devices: a cloverleaf plate, an angled blade-plate, and Kirschner wires. The effect of supplementing the fixation with SRS (Skeletal Repair System) calcium phosphate cement was evaluated as well. Eighteen pairs of fresh-frozen humeri were obtained, and the bone-mineral density of each specimen was measured. In each pair, one specimen was secured with internal fixation alone and the contralateral specimen was secured with internal fixation combined with calcium phosphate cement. The specimens were tested cyclically in abduction and in external rotation for 250 cycles to evaluate interfragmentary motion. The specimens were then loaded to failure in external rotation to measure torsional load to failure and torsional stiffness. RESULTS: Overall, there were no significant differences between the specimens treated with the blade and cloverleaf plates, whereas the specimens treated with Kirschner wires demonstrated more interfragmentary motion, less stiffness, and lower torque to failure. In general, supplementation with calcium phosphate cement led to significant improvements in the mechanical performance of all three forms of internal fixation as demonstrated by a significant decrease in interfragmentary motion, a significant increase in torque to failure, and a significant increase in torsional stiffness. The addition of calcium phosphate cement increased the stiffness of even the most osteoporotic specimens to levels that were higher than those of the most osteodense specimens that had been treated with internal fixation alone. CONCLUSION: The initial biomechanical properties of internal fixation as measured with use of a proximal humeral osteotomy model and three methods of fixation were significantly improved by the addition of calcium phosphate cement.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| 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".