Common Physical Examination Tests for Patellofemoral Instability Demonstrate Weak Inter‐Rater Reliability
Bibliographic record
Abstract
PURPOSE: The purpose of this study was to assess the inter-rater reliability of 3 common physical examination assessments, the Q-angle, J-sign, and apprehension test, used to evaluate patients presenting with recurrent lateral patellofemoral instability. METHODS: A consecutive sample of 38 subjects with recurrent lateral patellofemoral instability in 2013 were included in this reliability study. Two orthopaedic surgeons performed the physical examination maneuvers blinded to each other. The physical examination tests were performed bilaterally and included the Q angle, the J-sign, and the apprehension test. To measure the inter-rater reliability, an intraclass correlation coefficient (ICC 2,κ) was used for both legs independently for Q-angle measurements. A Cohen's kappa was used to measure the inter-rater reliability for the J-sign and the apprehension test. RESULTS: The measurement of the Q-angle demonstrated poor reliability (ICC 2,κ 0.18-0.44). The assessment of the J-sign demonstrated fair to moderate reliability (κ = 0.31 - 0.41), and the evaluation of apprehension demonstrated fair to substantial reliability (κ = 0.30 - 0.65). All 3 clinical tests demonstrated substantial variability comparing the reliability on the right and left limbs. Assessment of the quality of apprehension demonstrated good agreement between the examiners. CONCLUSIONS: In this study of patients with recurrent lateral patellofemoral instability the common physical examination tests, Q-angle, J-sign, and apprehension demonstrated weak inter-rater reliability. These results indicate that these tests are not reliable for communication between health care practitioners or as evaluations for clinical research. LEVEL OF EVIDENCE: Level IV, therapeutic case series.
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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 | 0.034 | 0.082 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| 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".