Quadriceps Strength as a Predictor of Knee Osteoarthritis Progression
Bibliographic record
Abstract
Objective To determine whether quadriceps strength is associated with tibiofemoral osteoarthritis progression in persons with knee osteoarthritis. The association was examined particularly in malaligned knees and high-laxity knees. Design Cohort study. Setting Academic medical center in Chicago, Illinois. Participants Participants for a natural history study (Mechanical Factors in Arthritis of the Knee) were recruited through periodicals, organizations, and medical center referrals. Inclusion criteria were osteophyte presence in 1 or both knees and difficulty with ≥2 items in the Western Ontario and McMaster University osteoarthritis index physical function scale. Exclusion criteria were corticosteroid injection within 3 months, inflammatory arthritis, comorbidity in the lower limb, and replacement or planned replacement of the arthritic knee(s). Of 237 participants, 230 were followed for 18 months, and 171 (mean age, 64 years; 74% women) who did not have advanced osteoarthritis at baseline (Kellgren and Lawrence grade 4) were included in the analysis (328 knees). Assessment of risk factors Baseline measurements were obtained for both knees. Isokinetic quadriceps strength (maximal torque during movement) was assessed by means of a computer-driven isokinetic dynamometer. Alignment was measured on a single anterior radiograph of both lower extremities. A knee was considered malaligned if the angle of the intersection of the line between the centers of the femoral head and inter-condylar notch and the line between the centers of the ankle talus and tibial spines was 5° or more. High varus-valgus laxity (the sum of varus and valgus rotation for each knee measured at the foot) was defined as knees in the highest tertile (≥5.75°). Main outcome measures The main outcome measure was tibiofemoral osteoarthritis progression (an increase in the grade of joint space narrowing) determined radiographically at baseline and 18 months. Main results The predicted probability of arthritis progression, after adjustment for baseline age, body mass index, disease severity, and physical activity, was slightly greater in knees with greater quadriceps strength (>47.3 ft-lb) compared with lesser quadriceps strength (0.153 vs. 0.098; P = 0.09). In logistic regression, strength was associated with an increase in predicted probability of disease progression in malaligned knees (n = 78; high strength, 0.406. vs. low strength, 0.187; P = 0.03), but not in neutrally aligned knees (n = 250; P > 0.2). High strength in the knees with high laxity (≥5.75°; n = 110) and in knees with the greatest laxity (≥6.75°; n = 70) was associated with a greater probability of arthritis progression (P = 0.05 and P = 0.003, respectively). Conclusions Quadriceps strength was not found to be beneficial in reducing the progression of tibiofemoral knee osteoarthritis in older adults. Quadriceps strength was predictive of more severe arthritis progression in malaligned knees and in knees with high laxity.
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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 | 0.004 |
| 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 | 0.001 |
| 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".