Reproducing the Native Posterior Tibial Slope in Cruciate-Retaining Total Knee Arthroplasty: Technique and Clinical Implications
Bibliographic record
Abstract
Total knee arthroplasty (TKA) profoundly influences knee biomechanics. Using an arbitrary (often 3° to 5°) posterior tibial slope (PTS) in all cases seldom will restore native slope. This study examined whether the native PTS could be reproduced in cruciate-retaining TKA and how this would influence clinical outcome. Radiographic and clinical outcomes of 215 consecutive TKAs using the PFC sigma cruciate-retaining implant were evaluated. The tibial bone cut was planned to be made parallel to the native anatomical slope in the sagittal plane. The PTS was measured with reference to the proximal tibial medullary canal (PTS-M) and the proximal tibial anterior cortex (PTS-C) on true lateral radiographs using a picture achieving and communication system. Knee range of motion (ROM), Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Short Form Health Survey (SF-12) were evaluated. Mean preoperative PTS-M was 6.9°±3.3°, and mean postoperative PTS-M was 7.0°±2.4°. Mean preoperative PTS-C was 12.2°±4.2°, and mean postoperative PTS-C was 12.6°±3.4°. Preoperative and postoperative PTS were not significantly different for both techniques (P>.05). An arbitrary 3° as an acceptable range for PTS-M was achieved in 144 knees (67%) (group 1), and 71 knees (33%) had a difference of more than 3° (group 2). Group 1 had a significantly larger gain in ROM (P=.04) as well as improved Knee Society, WOMAC, and SF-12 physical scores compared with group 2 (P<.01). The modified surgical technique reproduced the native tibial slope in cruciate-retaining TKA. Reproduction of the native PTS within 3° resulted in better clinical outcomes manifested by gain in ROM and knee functional outcome scores. [Orthopedics. 2020; 43(1):e21-e26.].
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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 | 0.001 | 0.003 |
| 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 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".