Increasing risk of revision due to deep infection after hip arthroplasty

Figures & data

Table 1.  Primary THAs included over the four 5-year time periods.

Variable	1987–1992	1993–1997	1998–2002	2003–2007
No. of THAs	20,913	22,519	26,230	27,682
Sex (%)
Male	30	30	29	31
Female	70	70	71	69
Age (%)
< 40	2	2	2	1
40–59	15	14	15	14
60–69	31	27	26	26
70–79	41	43	41	39
≥ 80	12	14	17	19
Diagnosis (%)
Osteoarthritis	67	70	73	77
Inflammatory	4	4	4	3
Other	29	26	23	20
Prosthesis (%)
Monoblock	58	53	38	22
Modular	42	47	62	78
Duration (min) of surgery (%)
< 70	11	10	11	15
70–99	41	45	45	45
100–129	31	31	31	29
≥ 130	18	15	13	12
Operation room ventilation (%)
“Greenhouse”	12	2	1	1
Laminar flow	29	45	53	56
Ordinary	59	53	46	44
Antibiotic prophylaxis systemically (%)
No	8	0	0	0
Yes	92	100	100	100
Method of fixation (%)
Uncemented	15	15	14	16
Cement
with antibiotics	38	56	82	83
without antibiotics	48	29	4	2

Table 2.  Risk ratios and 5-year survival estimates for revision due to deep infection. The risk ratios and survival estimates are adjusted for sex, age, diagnosis, prosthesis, operation room ventilation, duration of operation, and antibiotic prophylaxis.

Prosthesis	Time period	No. of THAs included	No. of THAs revised due infection	Risk ratio	p-value	95% CI	5-year survival
All THAs	1987–1992	20,913	134	1			99.7
	1993–1997	22,519	156	1.3	0.03	1.0–1.7	99.6
	1998–2002	26,230	150	1.5	0.003	1.2–2.0	99.5
	2003–2007	27,682	174	3.0	< 0.001	2.2–4.0	99.1
Cemented THAs	1987–1992	17,867	119	1			99.7
	1993–1997	19,191	133	1.3	0.04	1.0–1.7	99.5
	1998–2002	22,558	129	1.5	0.008	1.1–2.1	99.5
	2003–2007	23,380	136	2.7	< 0.001	1.9–3.7	99.2
Uncemented THAs	1987–1992	3,046	15	1			99.8
	1993–1997	3,328	23	1.2	0.6	0.6–2.4	99.8
	1998–2002	3,672	21	1.4	0.3	0.7–2.9	99.6
	2003–2007	4,302	38	5.3	< 0.001	2.6–10.7	98.9
Charnley with antibiotics in the cement and systemically	1987–1992	4,321	26	1			99.7
	1993–1997	7,776	46	1.1	0.6	0.7–1.9	99.6
	1998–2002	9,301	44	1.1	0.9	0.6–1.8	99.6
	2003–2007	5,925	37	2.0	0.02	1.1–3.5	99.3

Figure 1.  Percentage revision due to deep infection, for all THAs, for cemented THAs, and for uncemented THAs, for 4 periods of primary surgery, adjusted for sex, age, diagnosis, prosthesis, operation room ventilation, duration of operation, and antibiotic prophylaxis.

Figure 2.  Graphical display of the relationship between year of primary surgery and risk of revision due to deep infection (with 95% CI) for all THAs, cemented THAs, uncemented THAs, and Charnley THAs with uniform antibiotic prophylaxis, adjusted for sex, age, diagnosis, prosthesis, operation room ventilation, duration of operation, type of fixation, and antibiotic prophylaxis.

Figure 3.  Percentage revision due to aseptic loosening, for all THAs, for 4 periods of primary surgery, adjusted for sex, age, diagnosis, prosthesis, operation room ventilation, duration of operation, type of fixation, and antibiotic prophylaxis.

Table 3.  Number of primary THAs included and number of reported first revisions due to deep infection. Adjusted risk ratio estimates for sex, age, diagnosis, type of prosthesis, duration of operation, operation room ventilation, antibiotic prophylaxis systemically, and type of fixation. The risk factors are adjusted for all the other risk factors in addition to year of surgery.

	No. of included	THAs revised due to infection	Risk ratio	p-value	95% CI
Sex
Male	29,216	311	2.5	< 0.001	2.1–2.9
Female	68,128	303	1
Age
< 40	1,721	9	0.5	0.1	0.3–1.1
40–59	14,240	95	0.8	0.2	0.6–1.1
60–69	26,336	196	1.1	0.3	0.9–1.3
70–79	39,812	241	1
≥ 80	15,235	73	0.9	0.5	0.7–1.2
Diagnosis
Osteoarthritis	70,134	440	1
Inflammatory	3,522	22	1.1	0.6	0.7–1.7
Other	23,688	152	1.2	0.1	1.0–1.4
Prosthesis
Modular	57,374	332	0.8	0.1	0.7–1.0
Monoblock	39,970	282	1
Duration of surgery, min
< 70	11,334	55	0.9	0.5	0.7–1.2
70–99	42,700	236	1
100–129	29,679	211	1.3	0.01	1.0–1.5
≥ 130	13,631	112	1.5	0.001	1.2–1-9
Operation room ventilation
Greenhouse	3,386	30	1.3	0.2	0.9–2.0
Laminar flow	45,620	324	1.3	0.006	1.1–1.5
Ordinary	48,338	260	1
Antibiotic prophylaxis systemically
No	1,820	15	1.6	0.1	0.9–2.7
Yes	95,524	599	1
Method of fixation
Uncemented	14,348	97	1.4	0.03	1.0–1.8
Cement
with antibiotics	65,005	360	1
without antibiotics	17,991	157	1.9	< 0.001	1.5–2.3