Table 2.

Patient and procedure related risk factors for revision due to infection after primary TKA

Variables	No	RR (95% CI) Unadjusted p-value		RR (95% CI) Adjusted	p-value
Age
60-69	9717	1		1
< 60	4989	0.9 (0.7-1.3)	0.7	0.9 (0.7-1.3)	0.6
70-79	10,009	0.8 (0.6-1.0)	0.1	0.8 (0.6-1.1)	0.1
> 80	3547	0.7 (0.5-1.1)	0.1	0.7 (0.5-1.1)	0.1
Sex
men	10,186	1		1
women	18,076	0.5 (0.4-0.6)	<0.001	0.5 (0.4-0.6)	<0.001
Diagnosis
OAa	25,152	1		1
Otherb	3110	1.6 (1.2-2.1)	0.004	1.4 (1.0-2.0)	0.04
ASA
1	4167	1		1
2	17,918	1.1 (0.8-1.5)	0.7	1.2 (0.8-1.7)	0.4
3+	5621	1.7 (1.2-2.5)	0.005	1.8 (1.2-2.7)	0.003
Hospital volume
1-49	3953	1		1
50-99	10,615	1.1 (0.8-1.6)	0.5	1.1(0.8-1.6)	0.5
100-149	6379	1.2 (0.8-1.7)	0.4	1.1 (0.7-1.7)	0.6
≥ 150	7315	1.2 (0.8-1.7)	0.4	1.1 (0.7-1.7)	0.6
Perioperative complications
no	27,068	1		1
yes	640	2.3 (1.4-3.9)	0.002	2.1 (1.3-3.6)	0.004
Computer navigation
no	23,626	1		1
yes	2462	1.0 (0.7-1.5)	1.0	1.0 (0.7-1.5)	1.0
Prior fracturec
no	27,711	1		1
yes	551	2.20(1.1-3.6)	0.02	1.5 (0.8-2.7)	0.2
Prior osteotomyd
no	27,377	1		1
yes	885	0.9 (0.5-1.8)	0.8	0.8 (0.4-1.5)	0.5
TKA implant brands
LCS Complete	8752	1		1
AGC	2233	0.8 (0.5-1.3)	0.3	0.8 (0.5-1.3)	0.3
LCS	516	1.1 (0.5-2.3)	0.9	1.3 (0.6-2.9)	0.5
Duracon	2043	1.6 (1.1-2.3)	0.02	1.5 (0.8-2.7)	0.2
NexGen	4717	1.2 (0.8-1.6)	0.4	1.0 (0.7-1.4)	1.0
Profix	6286	0.9 (0.6-1.2)	0.4	0.9 (0.6-1.2)	0.4
PFC Sigma	697	1.0 (0.4-2.3)	1.0	0.9 (0.4-2.0)	0.7
Triathlon	1317	1.0 (0.6-1.8)	1.0	0.9 (0.5-1.5)	0.6
Vanguard TM	741	0.3 (0.1-1.0)	0.06	0.2 (0.1-0.8)	0.03
Otherse	955	0.4 (0.1-1.0)	0.05	0.4 (0.1-1.0)	0.06
Time Period
2005-2009	12,362	1		1
2010-2014	15,900	1.3 (1.0-1.6)	0.03	1.3 (1.0-1.6)	0.08

^aOA = Osteoarthritis

^bOther = other diagnosis than osteoarthritis, e.g. inflammatory diseases

^cIntraarticular fracture or fracture in proximity to the joint with previous osteosynthesis

^dPrevious knee osteotomy for knee malalignment

^eImplant brands used in smaller numbers than 500 during the time period from 2005 to 2014