Association of Femoroacetabular Impingement and Delayed Gadolinium‐Enhanced Magnetic Resonance Imaging of Cartilage: A Population‐Based Study
Bibliographic record
Abstract
OBJECTIVE: To assess the association of femoroacetabular impingement (FAI) and delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) T1 relaxation values (RVs), and to evaluate whether subtypes of FAI (cam, pincer, and mixed) are associated with region-specific dGEMRIC T1 RVs. METHODS: A population-based sample of white subjects with and without hip pain, ages 20-49 years, was selected through random-digit dialing. A sample of 128 subjects underwent hip-joint 3T dGEMRIC scans. Radiographic cam FAI was defined as an alpha angle >55°, while pincer FAI was defined by a lateral center edge angle >40°, or a positive cross-over sign. Mixed impingement was defined by the presence of both cam and pincer impingement. Overall and region-specific T1 RVs were compared between all FAI subtypes, using weighted linear regression analysis to account for sampling design of the study. RESULTS: Subjects had a mean age of 38 years and 51% were female. We did not find an association of FAI with overall hip T1 RV (mean difference -15.5 [95% confidence interval -77.23, 47.14]). Significant associations of cartilage degeneration in anterior superior and central superior regions were found in subjects with mixed FAI compared to other FAI subtypes and non-FAI subjects. CONCLUSION: Subjects with mixed FAI had reduced T1 RVs compared to other FAI subtypes. No substantial cartilage degeneration was found in pure cam or pincer FAI compared to no-FAI hips. These results indicate that the presence of cam or pincer impingements alone does not suggest the beginning of cartilage degeneration. In contrast, the presence of both FAI subtypes is a risk factor for early cartilage damage.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".