Surgical procedures in the treatment of 784 infected THAs reported to the Norwegian Arthroplasty Register

Figures & data

Figure 1. Flow chart showing the entire THA cohort and the different subgroups of surgical revision procedures (number and percentage) for revisions performed for any cause and due to infection.

Table 1. Descriptive data on 2-stage revision, 1-stage revision, major partial 1-stage exchange (i.e. exchange of stem or cup), and minor partial 1-stage exchange (i.e. exchange of head and/or liner) for infected THAs in the period 1987–2009

Type of revision	No. of revisions (%)	Mean age at revision (years) ^a	Females %	Mean duration of operation (min) ^a	Mean interval: operation to revision (years) ^a
2-stage	283 (36%)	71 (9; 34–88)	52%	320 (91; 155–780) ^b	2.9 (3.0; 0.1–16)
1-stage	192 (25%)	72 (9; 42–90)	45%	167 (59; 65–380)p < 0.001	2.9 (3.0; 0.0–15)p = 1.00
Major partial exchange	129 (17%)	70 (11; 31–89)	51%	139 (49; 35–300)p < 0.001	3.1 (3.4; 0.0–19)p = 1.00
Minor partial exchange	180 (23%)	72 (11; 38–92)	54%	94 (33; 35–320)p < 0.001	0.7 (2.0; 0.0–13)p < 0.001
Total	784 (100%)	71 (10; 31–92)	51%	202 (115; 35–780 )	2.4 (3.0; 0.0–19)

^a Values are mean (SD; min–max)

^b The duration of operation for 2-stage revision includes first stage with removal of the implant (171 (62; 45–445)) and second stage with re-implantation (149 (48; 35–450)).

Table 2. Results of the first revision for infected THA in the period 1987–2009 with any reason for revision and with infection as endpoints in the analyses for 2-stage revision, 1-stage revision, major partial 1-stage exchange (i.e. exchange of stem or cup), and minor partial 1-stage exchange (i.e. exchange of head and/or liner). Number of THAs, number of re-revisions (with complete dataset in the Cox analyses), Kaplan-Meier (KM) 2-year revision percentages, Cox relative revision risk (RR) (with 2-stage revision as reference), 95% confidence interval for RR, and p-value

Endpoint in the analyses	THA (%)	Re-revisions	2-year KM survival	RR ^a	95% CI	p-value
Any reason for revision:	784 (100%)	180 (23%)	83%
2-stage revision	283 (36%)	38 (13%)	92%	1	–	–
1-stage revision	192 (25%)	38 (20%)	88%	1.4	0.9–2.1	0.2
Major partial exchange	129 (17%)	64 (50%)	66%	4.1	2.8–6.2	< 0.001
Minor partial exchange	180 (23%)	40 (22%)	76%	1.5	0.9–2.5	0.1
Infection:	784 (100%)	108 (14%)	88%
2-stage revision	283 (36%)	15 (5%)	96%	1	–	–
1-stage revision	192 (25%)	22 (11%)	92%	2.0	1.1–3.9	0.04
Major partial exchange	129 (17%)	37 (29%)	74%	6.0	3.3–11.0	< 0.001
Minor partial exchange	180 (23%)	34 (19%)	80%	2.3	1.2–4.5	0.02

^a Adjusted in the Cox model for sex, type of fixation, type of prosthesis, and age at revision.

Figure 2. Cox-adjusted survival curves for first revision due to infected THA for the whole period 1987–2009 with any reason for re-revision (panel A) and infection (panel B) as endpoints in the analyses for 2-stage revision, 1-stage revision, major partial 1-stage exchange (i.e. exchange of stem or cup), and minor partial 1-stage exchange (i.e. exchange of head and/or liner).

Figure 3. Interval between the primary THA and the first revision performed in the period 1987–2009, for 2-stage revision, 1-stage revision, and major and minor partial exchange.

Figure 4. Number of first revisions per year for THAs carried out between 1987 and 2009 with the 2-stage procedure (283 revisions), 1-stage procedure (192 revisions), major partial 1-stage exchange (i.e. exchange of stem or cup) (129 revisions), and minor partial 1-stage exchange (i.e. exchange of the liner or head) (180 revisions).

Table 3. Descriptive data on 2-stage revision, 1-stage revision, major partial 1-stage exchange (i.e. exchange of stem or cup), and minor partial 1-stage exchange (i.e. exchange of head and/liner) for infected THAs in the period 2002–2009

Type of revision	No. of revisions (%)	Mean age at revision (years) ^a	Females %	Mean duration of operation (min) ^a	Mean interval: operation to revision (years) ^a
2-stage revision	164 (34%)	71 (10; 39–87)	49%	330 (94; 175–780) ^b	3.2 (3.5; 0.1–16.3)
1-stage revision	86 (18%)	73 (10; 42–89)	43%	168 (63; 70–380) p < 0.001	3.7 (3.7; 0.2–14.9) p = 1.00
Major partial exchange	61 (13%)	71 (13; 31–89)	48%	139 (48; 40–265) p < 0.001	3.7 (4.3; 0.0–19.0) p = 1.00
Minor partial exchange	178 (36%)	71 (11; 38–89)	53%	95 (34; 35–320) p < 0.001	0.7 (2.0;0.0–13.1) p < 0.001
Total	489 (100%)	71 (10; 38–89)	50%	197 (121; 35–780 )	2.5 (3.5; 0.0–19.0)

^a Values are mean (SD; min–max)

^b The duration of operation for 2-stage revision includes first stage with removal of the implant (179 (64; 45–445)) and second stage with re-implantation (151 (52; 70–450)).

Table 4. Results of the first revision for infected THA in the period 2002–2009 with any reason for re-revision and with infection as endpoints in the analyses for 2-stage revision, 1-stage revision, major partial 1-stage exchange (i.e. exchange of stem or cup), and minor partial 1-stage exchange (i.e. exchange of head and/or liner). Number of THAs, number of re-revisions (with complete dataset in the Cox analyses), Kaplan-Meier (KM) 2-year revision percentages, Cox relative revision risk (RR) (with 2-stage revision as reference), 95% confidence interval for RR, and p-value

Endpoint in the analyses	THA (%)	Re-revisions	2-year KM survival	RR ^a	95% CI	p-value
Any reason for revision:	489 (100%)	100 (23%)	83%
2-stage revision	164 (34%)	15 (9%)	94%	1	–	–
1-stage revision	86 (18%)	11 (13%)	87%	1.3	0.6–2.8	0.5
Major partial exchange	61 (12%)	34 (56%)	57%	7.4	4.0–13.8	< 0.001
Minor partial exchange	178 (36%)	40 (22%)	78%	1.9	1.0–3.8	0.05
Infection:	489 (100%)	77 (16%)	86%
2-stage revision	164 (34%)	9 (5%)	98%	1	–	–
1-stage revision	86 (18%)	8 (9%)	89%	1.6	0.6–4.2	0.4
Major partial exchange	61 (12%)	26 (43%)	63%	9.0	4.2–19.5	< 0.001
Minor partial exchange	178 (36%)	34 (19%)	80%	2.5	1.1–5.8	0.03

^a Adjusted in the Cox model for sex, type of fixation, type of prosthesis, and age at revision.

Figure 5. Cox-adjusted survival curves for first revision due to infected THA for 2002–2009 with any reason for re-revision (panel A) and infection (panel B) as endpoints in the analyses for 2-stage revision, 1-stage revision, major partial 1-stage exchange (i.e. exchange of stem or cup), and minor partial 1-stage exchange (i.e. exchange of head and/or liner) .