TABLE I.

Knee Arthroscopy Descriptive Characteristics

	2009	2010	2011	2012	2013
CalPERS
No. of procedures	884	856	953	828	808
Performed at ambulatory surgery center	529	532	593	559	598
Performed at hospital outpatient department: not exempt	355	324	360	186	131
Performed at hospital outpatient department: exempt	0	0	0	83	79
Procedure payment*	$5146	$5412	$5638	$5395	$5402
Hospital outpatient departments*	$6717	$7016	$7565	$6640	$7534
Ambulatory surgery centers*	$4092	$4435	$4469	$4795	$4653
Charlson Comorbidity Index score*	0.3	1.2	1	0.1	0.7
Male patients	47.70%	47.40%	46.80%	46.60%	49.90%
Patient age* (yr)	50.7	50.6	50.2	50.3	50.7
Ninety-day complications
Complication rate*	1.92%	1.40%	1.89%	1.69%	2.48%
No. of complications	17	12	18	14	20
Anthem
No. of procedures	7997	7830	7667	7925	8347
Performed at ambulatory surgery center	2824	2658	2541	2616	2913
Performed at hospital outpatient department	5173	5172	5126	5309	5434
Procedure payment*	$4824	$4946	$5205	$5378	$5568
Hospital outpatient departments*	$6380	$7056	$7158	$7139	$7409
Ambulatory surgery centers*	$3975	$3862	$4236	$4510	$4581
Charlson Comorbidity Index score*	0.8	0.6	0.6	0.7	0.6
Male patients	58.30%	57.00%	57.10%	56.40%	57.00%
Patient age* (yr)	45.8	46.4	46.2	46.1	46.3
Ninety-day complications
Complication rate*	1.90%	1.86%	1.71%	1.83%	1.76%
No. of complications	152	146	131	145	147

^*The values are given as the mean.