VALIDATION OF TWO AND THREE-DIMENSIONAL RADIOGRAPHIC TECHNIQUES FOR MEASURING POLYETHYLENE WEAR AFTER TOTAL HIP ARTHROPLASTY
Bibliographic record
Abstract
BACKGROUND: Three-dimensional radiographic techniques have been developed to estimate in vivo polyethylene wear of total hip replacements. We are not aware of any published study examining the accuracy of these in vivo methods. Our objective was to validate two radiographic techniques by comparing their results with those obtained directly from retrieved specimens. METHODS: A coordinate measuring machine was used to probe the interior bearing surface of seventeen acetabular liners that had been retrieved at revision surgery. Solid models were created to determine volumetric polyethylene loss and linear depth and direction of wear. Two in vivo radiographic techniques (PolyWare and the Martell Hip Analysis Suite) were used to calculate two-dimensional linear, three-dimensional linear, and volumetric wear. The radiographic analysis was done independently, and the results were compared with the known values of polyethylene wear derived with use of the coordinate measuring machine. RESULTS: Correlation coefficients comparing the values for two-dimensional and three-dimensional linear wear and volumetric wear derived with the PolyWare radiographic technique with the values derived with the coordinate measuring machine were r(2) = 0.78, r(2) = 0.75, and r(2) = 0.91, respectively (all p < 0.001), and the correlation coefficients comparing the values derived with the Martell Hip Analysis Suite radiographic technique with those derived with the coordinate measuring machine were r(2) = 0.80, r(2) = 0.84, and r(2) = 0.91, respectively (p < 0.001). The average absolute difference between the radiographic estimates and the results derived with the coordinate measuring machine was approximately 19% (range, 13% to 24%). CONCLUSIONS: There was good agreement between the wear estimates made with both in vivo techniques and the measurements of the retrieved polyethylene liners made with the coordinate measuring machine. Two-dimensional wear analysis (based on anteroposterior radiographs) accounted for most of the polyethylene wear, while one technique of three-dimensional wear analysis (PolyWare) demonstrated some additional wear in the lateral plane.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.013 | 0.041 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".