Factors affecting risk of knee replacement
| Univariate analysis | Multivariate analysis* | 95% CI | p Value | |
|---|---|---|---|---|
| *Multivariate analysis with age, sex, BMI, % tibial cartilage loss, WOMAC score, and bone size in regression equation. | ||||
| †Change per five year increase in age. | ||||
| ‡Change per 100 mm2 increase in tibial bone area. | ||||
| §Change per 1% increase in tibial cartilage loss. | ||||
| ¶Change per 100 unit increase in WOMAC score. | ||||
| **Based on Kellgren–Lawrence grade: change per unit increase in grade. | ||||
| BMI, body mass index; CI, confidence interval; F, female; M, male; OA, osteoarthritis; WOMAC, Western Ontario and McMaster Universities osteoarthritis index | ||||
| Age† | 0.005 | 0.9 | 0.7 to 1.3 | 0.55 |
| Sex (F v M) | 2.3 | 9.9 | 1.5 to 65.4 | 0.02 |
| BMI | 0.05 | 0.9 | 0.8 to 1.1 | 0.38 |
| Tibial bone area‡ | 0.001 | 1.2 | 1.0 to 1.4 | 0.02 |
| Per cent tibial cartilage loss§ | 0.10 | 1.2 | 1.1 to 1.3 | 0.008 |
| WOMAC¶ | 0.002 | 1.5 | 1.1 to 2.0 | 0.01 |
| Radiological grade of OA** | 0.77 | 1.8 | 0.6 to 6.1 | 0.32 |