Table 2.
WOMAC pain and function scores stratified by BMI before and 2 and 4 weeks after TKA.
| Normal Weight | Overweight | Obese | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| WOMAC | n | Estimated Mean |
(95% CI) | n | Estimated Mean |
(95% CI) | n | Estimated Mean |
(95% CI) | |
| Pain † | Pre | 30 | 40.85 | (33.16, 48.53) | 49 | 36.83 | (29.59, 44.08) | 23 | 35.22 | (25.53, 44.91) |
| 2w | 25 | 28.15 | (19.90, 36.40) | 46 | 26.67 | (19.35, 33.99) | 21 | 24.30 | (14.38, 34.21) | |
| 4w | 24 | 21.64 | (13.28, 30.00) | 45 | 17.92 | (10.55, 25.29) | 21 | 14.54 | (4.62, 24.45) | |
| Time effect (with respect to preoperative score): 2w, p = 0.001 *; 4w, p < 0.001 *. | ||||||||||
| Group effect (relating to normal weight group): Overweight, p = 0.344; Obese, p = 0.280. | ||||||||||
| Group-by-time interaction effect (relating to normal weight group by preoperative score): | ||||||||||
| Overweight × 2w, p = 0.603; Obese × 2w, p = 0.953. | ||||||||||
| Overweight × 4w, p = 0.760; Obese × 4w, p = 0.800. | ||||||||||
| Normal weight | Overweight | Obese | ||||||||
| WOMAC | n |
Estimated
mean |
(95% CI) | n |
Estimated
mean |
(95% CI) | n |
Estimated
mean |
(95% CI) | |
| Function † | Pre | 30 | 28.34 | (22.17, 34.51) | 49 | 24.13 | (18.37, 29.90) | 23 | 30.41 | (22.67, 38.15) |
| 2w | 25 | 24.78 | (18.12, 31.45) | 46 | 24.08 | (18.25, 29.91) | 21 | 25.35 | (17.42, 33.28) | |
| 4w | 24 | 13.34 | (6.59, 20.10) | 45 | 11.28 | (5.41, 17.16) | 21 | 14.29 | (6.35, 22.22) | |
| Time effect (with respect to preoperative score): 2w, p = 0.288; 4w, p < 0.001 *. | ||||||||||
| Group effect (relating to normal weight group): Overweight, p = 0.221; Obese, p = 0.792. | ||||||||||
| Group-by-time interaction effect (relating to normal weight group by preoperative score): | ||||||||||
| Overweight × 2w, p = 0.402; Obese × 2w, p = 0.611. | ||||||||||
| Overweight × 4w, p = 0.763; Obese × 4w, p = 0.823. | ||||||||||
The values represent the estimated marginal mean and 95% confidence interval. Abbreviations: WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; TKA: total knee arthroplasty; BMI: body mass index; CI: confidence interval; 2w: 2 weeks post TKA; 4w: 4 weeks post TKA; n: number. Normal weight: BMI ≤ 24.99 kg/m2, overweight: 25 ≤ BMI ≤ 29.99 kg/m2, obese: BMI ≥ 30 kg/m2. Generalized linear mixed models were used for the analysis. The dependent variables were WOMAC pain (Model 1) and function scores (Model 2). The fixed effects included in the models were group, time, group × time, etiology (osteoarthritis vs. rheumatic arthritis), age, sex, and comorbidities (assessed using the Charlson Comorbidity Index). Participants were included as random effects. The goodness-of-fit for Models 1 and 2 was as follows: 23,454 and 2254, respectively, for corrected Akaike’s information criteria (AIC); 2361 and 2261, respectively, for the Bayesian information criteria (BIC); 0.498 and 0.449 for the interclass correlation coefficient (ICC); and 0.387 and 0.310, respectively, for variance explained (R2). * p < 0.05. † The scale is from 0 to 100, with 100 denoting the worst outcome.