Reproducibility of a simplified Q-angle measurement technique
Bibliographic record
Abstract
Background The Q-angle test is routinely used by clinicians specializing in orthopaedics to assess the line of pull of the quadriceps muscle at the patellofemoral joint. Research has found that this tests' reliability is influenced by a host of procedural and anthropometric variables. As a result, the diagnostic relevance of using the Q-angle measurement in the clinical assessment of patellofemoral joint alignment has been called into question. Our hypothesis was that a “simplified” Q angle (SQA) technique is clinically reliable. Methods Participants (n=54) were between the ages of 18 and 45 years, with no history of acute trauma. The SQA technique was adapted from the “traditional” Q angle (TQA) test protocol. It uses the same superior (ASIS) and inferior (TT) landmarks as the TQA protocol, but instead of using the mid-point of the patella as the location of intersection between the superior and inferior vectors, the SQA technique uses the mid-point of the quadriceps tendon, immediately superior to the base of the patella. Board certified therapists assessed SQA in supine participants. A re-test session was completed 7 to 10 days later. Results The intraclass correlation (ICC) values illustrated moderate to high levels of intra-rater (ICC: 0.69, 95%CI: 0.58-0.78) and inter-rater (ICC: 0.77, 95%CI: 0.71-0.82) reliability. Measurement error values illustrated the reliability limits (CV: 2°, ME: 2°, CV: 17%) of the technique, as well as the minimum difference (MD: 5°) required between repeated testing sessions to conclude that a “real” change has occurred in measurements. Conclusions Results demonstrated that the SQA technique had higher levels of reliability than have been reported in the literature for the TQA measurement. This knowledge has important implications for clinicians who routinely use Q angle measurements as part of their decision-making paradigm when dealing with patellofemoral joint-related pathologies.
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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 | 0.042 | 0.093 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".