Design and Validation of an Unconstrained Loading System to Measure the Envelope of Motion in the Rabbit Knee Joint
Bibliographic record
Abstract
An unconstrained loading system was developed to measure the passive envelope of joint motion in an animal model commonly used to study ligament healing and joint arthritis. The design of the five-degree-of-freedom system allowed for unconstrained knee joint loading throughout flexion with repeated removal and reapplication of the device to a specimen. Seven New Zealand White rabbit knees were subjected to varus, valgus, internal and external loads, and the resulting envelopes of motion were recorded using an electromagnetic tracking device. Intra-specimen reproducibility was excellent when measured in one specimen, with maximal rotational differences of 0.6 and 0.3 deg between the fourth and fifth testing cycles for the varus (VR) and valgus (VL) envelopes, respectively. Similarly, the maximal internal (INT) and external (EXT) envelope differences were 0.5 and 0.4 deg, respectively, between the fourth and fifth cycles. Good inter-animal envelope reproducibility was also observed with consistent motion pathways for each loading condition. A maximal VR-VL laxity of 17.9 +/- 2.3 deg was recorded at 95 deg flexion for the seven knees tested. The maximal INT-EXT laxity of 75.2 +/- 4.8 deg occurred at 50 deg flexion. Studies on measurement reproducibility of re-applying individual testing components demonstrated a maximal error of 1.2 +/- 0.7 deg. Serial removal and re-application (test-retest) of the complete measuring system to one cadaveric knee demonstrated maximal envelope differences of less than 0.7 deg for VR-VL rotation and 2.1 deg for INT-EXT rotation. Our results demonstrate that the measuring system is reproducible and capable of accurate evaluation of knee joint motion. Baseline in vitro data were generated on normal joint kinematics for future in-vivo studies with this system, evaluating ligament healing and disease progression in arthritis models.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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 teacher head, 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".