Table 1.

Patient, surgeon, implant, and hospital characteristics for the total THA cohort, 2001–2011

Variables		All		Bearing surface
				Conventional polyethylene		HXLPE
		Number	Percent	Number	Percent	Number	Percent
		26,823		1815	7	25,008	93
Sex	Male	10,649	40	653	36	9996	40
	Female	16,170	60	1160	64	15,010	60
	Missing	4	<0.01	2	0.1	2	<0.01
ASA category	1 or 2	15,374	57	1028	57	14,346	57
	≥ 3	10,704	40	706	39	9998	40
	Unknown	745	3	81	5	664	3
BMI category (kg/m2)	< 30	16,233	61	1088	60	15,145	61
	≥ 30 and < 35	6263	23	370	20	5893	24
	≥ 35	3857	14	214	12	3643	15
	Unknown	470	2	143	8	327	1
Race	Asian/Pacific Islander	886	3	94	5	792	3
	Black	1882	7	61	3	1821	7
	Native American	41	0.2	4	0.2	37	0.1
	White	20,559	77	1232	68	19,327	77
	Hispanic	1804	7	114	6	1690	7
	Other	358	1	46	3	312	1
	Unknown	1293	5	264	15	1029	4
Diabetes	Yes	6239	23	468	26	5771	23
Surgeon fellowship	Yes	10,893	41	718	40	10,175	41
	Missing	45	0.2	0	<0.1	45	0.2
Surgeon average annual volume category	< 10	1448	5	71	4	1377	6
	10 to < 50	16,097	60	1145	63	14,952	60
	≥ 50	9276	35	599	33	8677	35
	Missing	2	<0.01	0	<0.1	2	<0.01
Site average annual volume category	< 100	4436	17	395	22	4041	16
	100 to < 200	13,703	51	889	49	12,814	51
	≥ 200	8682	32	531	29	8151	33
	Missing	2	<0.01	0	0.1	2	<0.01
Fixation	Uncemented	20,991	78	727	40	20,264	81
	Hybrid	3871	14	914	50	2957	12
	Cemented	181	1	26	1	155	1
	Missing	1780	7	148	8	1632	7
Head size	≤ 28 mm			1420	78	3773	15
	32 mm			341	19	10,420	42
	36 mm			54	3	9620	38
	> 36 mm			0	0.2	1195	5
Cup Type	Converge (Zimmer, Warsaw, IN, USA)			0	<0.1	463	2
	Duraloc (DePuy Synthes, Warsaw, IN, USA)			382	21	764	3
	Other			101	6	732	3
	Pinnacle (DePuy Synthes)			9	1	12,877	52
	Reflection (Smith & Nephew, Memphis, TN, USA)			753	42	4449	18
	S-Rom (DePuy Synthes)			133	7	14	<0.01
	Sector (DePuy Synthes)			49	3	523	2
	Trabecular Metal (Zimmer)			1	<0.1	3160	13
	Trident (Stryker, Kalamazoo, MI, USA)			369	21	353	1
	Trilogy Ace (Zimmer)			1	0.1	1624	7

	Mean	SD	Mean	SD	Mean	SD
Membership termination
Yes	2159	8	284	16	1875	8
Operative time (minutes)	93	34	98	33	93	34
Age (years)	70	10	72	10	69	10
BMI (kg/m2)	29	6	29	6	29	6
Days of followup	1286	973	2361	970	1208	926

HXLPE = highly crosslinked polyethylene; ASA = American Society of Anesthesiologists; BMI = body mass index.