Correlation Of Knee Alignment with Ankle and Hindfoot Alignment and Clinical Severity in Grade IV Osteoarthritis Knee: A Cross-Sectional Study
Bibliographic record
Abstract
Background: Osteoarthritis (OA) of the knee is a chronic degenerative disorder characterized by progressive joint deterioration. Coronal plane malalignment of the knee joint is frequently associated with advanced osteoarthritis. However, limited evidence exists regarding the relationship between knee alignment and concurrent ankle and hindfoot alignment changes in patients with severe knee OA. Objective: To evaluate the correlation of knee alignment with ankle and hindfoot alignment and clinical severity in patients with Grade IV knee osteoarthritis. Methods: This observational cross-sectional study was conducted at the Department of Physical Medicine and Rehabilitation, Safdarjung Hospital, New Delhi. Seventy-seven patients diagnosed with primary knee osteoarthritis (Kellgren-Lawrence Grade IV) according to American College of Rheumatology criteria were enrolled after obtaining informed consent. Knee alignment was assessed using hip-knee-ankle (HKA) angle on full-length weight-bearing anteroposterior radiographs. Ankle and hindfoot alignment were evaluated using five radiological parameters: angle between mid-diaphyseal line of tibia and calcaneus (ADTC), tibiotalar angle (TTA), tibial anterior surface angle (TAS), talar tilt angle (TT), and angle between ground surface and distal tibial plafond (GP). Clinical severity was assessed using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Health Assessment Questionnaire (HAQ), and Visual Analogue Scale (VAS). Spearman rank correlation coefficient was used for statistical analysis. Results: The mean age of participants was 59.98 ± 8.44 years, with 62.3% females. Mean disease duration was 6.67 ± 2.86 years. The mean HKA angle was 13.24 ± 3.92 degrees, indicating substantial varus malalignment. HKA showed statistically significant positive correlations with ADTC (r=0.262, p=0.001), TTA (r=0.330, p<0.001), TAS (r=0.343, p<0.001), and GP (r=0.421, p<0.001), with GP demonstrating the strongest correlation. No significant correlation was found with TT (r=-0.042, p=0.606). Mean clinical severity scores indicated severe disease burden: WOMAC 64.52 ± 5.45, HAQ 16.95 ± 3.18, and VAS 6.12 ± 0.54. HKA angle showed highly significant positive correlations with all clinical severity parameters: VAS (r=0.279, p<0.001), WOMAC (r=0.579, p<0.001), and HAQ (r=0.524, p<0.001), with WOMAC demonstrating the strongest association. Conclusion: Knee varus deformity in Grade IV osteoarthritis is significantly correlated with ankle and hindfoot malalignment, as well as clinical severity. The ground-plafond angle showed the strongest correlation with knee alignment among ankle-hindfoot parameters, while WOMAC score showed the strongest association with clinical outcomes. These findings suggest that knee osteoarthritis affects the entire lower extremity as an integrated biomechanical system. Comprehensive assessment including ankle and hindfoot evaluation may improve management planning and prognostic assessment in patients with severe knee osteoarthritis.
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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 | 0.002 |
| 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 | 0.000 |
| 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".