The influence of bony morphology on the magnitude of the pivot shift
Bibliographic record
Abstract
The purpose of this study was to correlate clinical pivot shift grading with femoral condyle size as measured on pre-operative magnet resonance imaging (MRI) of patients with anterior cruciate ligament (ACL) injury. Forty-nine consecutive patients for anterior cruciate ligament (ACL) surgery were examined under anesthesia. The pivot shift was graded according to Galway et al. and MacIntosh et al. by a single observer. The grade of pivot shift, Lachman, and collateral laxity was recorded. Intraoperative findings of injury patterns to the ACL and other soft tissue structures were recorded. The anterior-posterior (AP) and medial-lateral (ML) diameter of femoral condyles and tibial plateaus were measured on pre-operative MRI. Patients were grouped into a grade 1 pivot shift group and a grade 2 pivot shift group. ANOVA and independent t tests were used to compare bony dimensions between grade 1 and 2 pivot shifts and by sex. Significance was set at P < 0.05. Twenty-seven patients had a grade 1 pivot shift and 22 a grade 2 pivot shift. Associated pathology was present in 11/27 patients (41%) with a grade 1 pivot shift and 21/22 patients (95%) with a grade 2 pivot shift. The ML diameter of the lateral tibial plateau was significantly smaller in patients with a grade 2 pivot shift (35.5 +/- 3.7 mm) compared to patients with a grade 1 pivot shift (30.3 +/- 3.2 mm; P < 0.05). No difference was detected for any of the other measurements taken (NS). When analyzed by sex this difference existed in women (group I: 31.1 +/- 3.2, group II: 28.8 +/- 2.0; P < 0.05) but not in men (group I: 34.1 +/- 3.7, group II: 33.1 +/- 3.1; NS). All morphologic measurements were larger in men (P < 0.05). A smaller (ML) lateral tibial plateau diameter may contribute to a patient's higher-grade pivot shift. When analyzed by sex this was true for women but not for men. There are other factors contributing to the magnitude of the pivot shift, such as concomitant generalized laxity, injury to the knee joint capsule, and size/or injury of other soft tissue structures that were not analyzed in this study.
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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 | 0.000 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".