Table 3

Adjusted Complication Rates by Provider Volume, Patient Age, Comorbidity, Diagnosis and Gender

Variable	Complication; odds ratio (and 95% confidence limits)^*

	Readmission for knee infection		Readmission for kee revision		Patient death	In-hospital complications

	1 yr	3 yr	1 yr	3 yr	< 3 mo
Surgeon volume
Low < 14 v. high > 42	0.80 (0.4, 1.6)	0.88 (0.5, 1.3)	0.57 (0.2, 1.4)	1.00 (0.6, 1.7)	1.76 (0.80, 3.8)	0.98 (0.7, 1.3)

Mid 14–42 v. high > 42	0.84 (0.6, 1.2)	0.83 (0.6, 1.1)	0.91 (0.5, 1.6)	0.97 (0.7, 1.4)	1.61 (0.9, 2.7)	0.99 (0.76, 1.27)

Hospital volume
Low < 48 v. high > 113	1.57 (0.9, 2.7)	1.50 (0.9, 2.3)	2.23 (1.1, 4.5)	1.54 (1.0, 2.4)	1.38 (0.7, 2.9)	0.53 (0.39, 0.71)

Low 48–113 v. high > 113	1.11 (0.8, 1.6)	1.10 (0.8, 1.5)	1.57 (0.9, 2.9)	1.25 (0.9, 1.8)	1.30 (0.8, 1.5)	0.83 (0.63, 1.07)

Patient age, per 10 yr	0.90 (0.86, 0.97)	0.90 (0.85, 0.95)	0.77 (0.67, 0.89)	0.70 (0.66, 0.81)	2.44 (2.3, 2.6)	1.19 (1.1, 1.2)

Patient comorbidity
1 v. 0	0.67 (0.4, 1.6)	0.92 (0.6, 1.3)	1.15 (0.6, 2.1)	1.07 (0.7, 1.5)	5.36 (3.2, 8.9)	1.19 (1.0, 1.4)

> 1 v. 0	1.69 (0.9, 3.3)	2.14 (1.3, 3.6)	0.80 (0.2, 2.6)	0.88 (0.4, 1.8)	23.70 (13.3, 42.1)	2.05 (1.6, 2.62)

Diagnosis, osteoarthritis v. non-osteoarthritis	0.55 (0.3, 0.9)	0.75 (0.5, 1.2)	1.10 (0.5, 2.6)	1.26 (0.8, 2.1)	1.27 (0.7, 2.4)	0.96 (0.76, 1.22)

Patient gender, female v. male	0.80 (0.6, 1.0)	0.78 (0.6, 0.9)	0.91 (0.6, 1.3)	0.95 (0.7, 1.2)	0.66 (0.4, 1.0)	0.71 (0.6, 0.8)