Table 7. Estimates of BMI category coefficients to predict the mean increase or decrease in postoperative OKS.

	Unadjusted model			Adjusted model
	Coefficient	95% CI	p-value	Coefficient	95% CI	p-value
<18.5 kg/m2	−1.04	(−2.08, −0.01)	0.044	−0.74	(−1.75, 0.27)	0.150
18.5–24.99 kg/m2 (reference)	0.00			0.00
25–29.99 kg/m2	−0.24	(−0.42, −0.07)	0.005	−0.35	(−0.52, −0.18)	0.001
30–34.99 kg/m2	−1.07	(−1.24, −0.89)	<0.001	−1.10	(−1.27, −0.92)	<0.001
35–39.99 kg/m2	−1.96	(−2.16, −1.76)	<0.001	−1.82	(−2.02, −1.61)	<0.001
≥40 kg/m2	−2.83	(−3.07, −2.58)	<0.001	−2.20	(−2.46, −1.93)	<0.001

Adjusted model adjusts for age, sex, ASA grade, indication for operation, fixation type, year of primary TKR, and anxiety status.

ASA, American Society of Anaesthesiologists; BMI, body mass index; OKS, Oxford Knee Score; TKR, total knee replacement.