Is the Clock Face an Accurate, Precise, and Reliable Measuring Tool for Anterior Cruciate Ligament Reconstruction?
Bibliographic record
Abstract
PURPOSE: (1) To assess the use and practice of the clock face among surgeons who routinely perform anterior cruciate ligament (ACL) reconstructions, and (2) to assess the accuracy, precision, and reliability of 3 commonly used clock-face schemes in ACL reconstruction. METHODS: First, 9 surgeons completed a questionnaire assessing the use and definition of the clock-face technique. Next, to assess the accuracy, precision, and reliability of the clock face, each surgeon estimated the "time" of 8 artificial femur models with a black dot located on the posterior aspect of the lateral condylar wall. The estimates were performed using 3 different clock-face schemes and were repeated 10 months later. Solutions for each specimen were obtained by use of a computer graphical interface. RESULTS: More than half of the respondents (55%) use the clock face in ACL reconstructions, with the reported mean ideal "time" for a femoral tunnel in a right knee of 10:05 (SD, 31 minutes). When we accounted for the different clock definitions, this ideal position was found along the entire lateral condylar wall. In the assessment of the performance of the clock face, the mean error was 32 to 40 minutes (which translates to 3 to 4 mm) among the 3 clock schemes. The maximum error was 4 hours 0 minutes, and the range of responses was 1 hour 0 minutes to 4 hours 0 minutes depending on the specimen and clock scheme. Regardless of the clock scheme used, the intrarater and inter-rater reliabilities were similar-measuring, on average, 0.78 and 0.68, respectively. CONCLUSIONS: The clock face continues to be commonly used in ACL reconstruction. Different clock-face definitions affect the position for the same "time." When the clock-face parameters were strictly defined, there was good reliability with borderline accuracy and poor precision. CLINICAL RELEVANCE: Considering the borderline performance of the clock face in accuracy and poor precision, we recommend against using the clock face in ACL reconstruction.
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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 | 0.086 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| 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".