Table I.

Patient demographics according to BMI category.

Demographic	BMI < 40 kg/m2, n (%)	Morbidly obese, n (%)	p-value*
Female (n = 2,652)	2,389 (90.1)	263 (9.9)	< 0.001†
Male (n = 2,059)	1,930 (93.7)	129 (6.3)
THA (n = 2,370)	2,236 (94.3)	134 (5.7)	< 0.001‡
TKA (n = 2,109)	1,868 (88.6)	241 (11.4)	< 0.001§
UKA (n = 232)	215 (92.7)	17 (7.3)	0.714
Total (n = 4,711)	4,319 (91.6)	392 (8.4)	N/A

^*Fisher's exact test.

^†A significantly greater proportion of female patients (263/2,652; 9.9%) were morbidly obese compared to male patients (129/2059; 6.3%); Odds ratio 1.6 (95% confidence interval (CI) 1.3 to 1.9), p < 0.001.

^‡A significantly smaller proportion of Hip patients (134/2,370; 5.7%) were morbidly obese compared to all other patients (258/2,341; 11.0%); Odds ratio 0.5 (95% CI 0.4 to 0.6), p < 0.001.

^§A significantly greater proportion of Knee patients (241/2,109; 11.4%) were morbidly obese compared to all other patients (151/2,602; 5.8%); Odds ratio 2.1 (95% CI 1.7 to 2.6), p < 0.001.

N/A, not applicable; THA, total hip arthroplasty; TKA, total knee arthroplasty; UKA, unicompartmental knee arthroplasty.