Measurements of Surface and Subsurface Damage in Retrieved Polyethylene Tibial Inserts of a Contemporary Design
Bibliographic record
Abstract
In the present study, surface and subsurface damage due to wear and creep in retrieved tibial inserts from the Genesis II total knee replacement (Smith & Nephew, Memphis, TN) are quantified. The utility of a number of recently validated micro-computed tomography (micro-CT) techniques for use in retrieval studies are also demonstrated. Sixteen inserts retrieved from patients after an implantation time from 0.5 to 86 months were examined. The inserts were scanned using micro-CT, and the three-dimensional surface deviations (corresponding to wear and creep) between the retrieved inserts and a reference geometry were determined. The subsurface of the inserts was also examined. Deviations within damage features were measured, and a surface deviation rate (mm/ year) was calculated from the length of implantation. No subsurface fatigue damage was found. The mean deviation within the most damaged regions of the articular surface was 0.115 ± 0.064 mm medially and 0.099 ± 0.061 mm laterally (p = 0.20). The mean articular deviation rate for inserts in vivo for more than 1 year was 0.049 mm/year and was reduced to 0.026 mm/year in inserts implanted for more than 4 years. Wear and creep of the Genesis II PE insert was comparable to reported values in other total knee replacements.
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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 | 0.004 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".