Infectiological, functional, and radiographic outcome after revision for prosthetic hip infection according to a strict algorithm

Figures & data

Figure 1. The algorithm showing decision making for a 1-stage or 2-stage revision.

Figure 2. Flow of hips included in the study. Exclusion of 19 of 91 hips that did not fulfill the inclusion criteria.

Table 1. Patient characteristics prior to the index operation

		Matched ^a
	Control	p-value	Group 1	p-value	Group 2
Total hip arthroplasties (patients)	22 (22)		22 (21)		50 (48)
Age, median	67	0.4 ^b	69	0.2 ^b	70
range	53–84		48–88		40–88
Male	15	0.2 ^c	10	0.1 ^c	29
Charnley classification		0.9 ^d		0.15 ^d
A	12		14		31
B1	1		1		0
B2	9		7		17
C	0		0		2
Previous surgery performed	2	1.0 ^c	3	< 0.001 ^c	39
on trochanter	2	1.0 ^d	2	0.4 ^d	17
on cup, for any reason	1	0.3 ^d	0	0.002 ^d	23
on stem, for any reason	2	1 ^d	2	0.01 ^d	25
debridement(s)	0	1 ^d	0	< 0.001 ^d	70 ^e
Girdlestone/spacer	–		–		4/2
Proprosky classification cup		0.5 ^d	^f	0.004 ^d	^f
1	13		15		17
2A	3		1		5
2B	2		2		5
2C	2		2		12
3A	2		1		6
3B	0		0		4
Proprosky classification stem		0.6 ^d	^f	0.2 ^d	^f
I	0		1		1
II	17		16		19
IIIA	4		3		20
IIIB	1		1		2
IV	0		0		7
Deficient greater trochanter	1	1 ^c	1	0.05 ^c	12

^a Control and group 1 were matched for all listed variables.

^b Student t-test

^c Chi-square test.

^d Mann-Whitney U-test.

^e 16 hips received ≥ 2 (range 2–10) debridements.

^f One preoperative radiograph was not available.

Figure 3. A 59-year-old woman with bilateral PI following Staphylococcus aureus sepsis, 2 years after bilateral 1-stage exchange. On the right side: reconstruction with a Müller reinforcement ring for a type-1 defect, and a long Wagner stem by transfemoral approach. On the left side: a reconstruction with a Burch-Schneider ring to bridge a type-2B defect. A cemented Virtec stem with transgluteal approach was implanted. At the 2-year follow-up, the HHS (bilateral) was 97, there was a slight limp, there were no radiographic signs of loosening, the transfemoral osteotomy was healed, and the infection was cured.

Table 2. Surgical procedures and specifics at the index operation

		Matched ^a
	Control		Group 1		Group 2
Total hip arthroplasties (patients)	22 (22)	p-value	22 (21)	p-value	50 (48)
No osteotomy	14	0.5 ^b	15	0.2 ^b	22
Transfemoral osteotomy	7	0.5	5	0.1	22
Greater trochanter osteotomy	1	1	1	0.5	1
Approach via nonunion in greater trochanter	0	0.9	1	0.2	5
Spacer	–	–	–	–	29
Acetabular component					^c
SL uncemented cup	2	1 ^b	2	0.6 ^b	2
Müller reinforcement ring	16	1	16	0.08	24
Burch-Schneider reinforcement ring	4	1	4	0.03	23
Femoral component		1 ^b		0.8 ^b	^c
uncemented	11		11		26
cemented	11		11		23
Acetabular graft		0.2 ^d		0.9 ^d	^c
no graft	5		9		27
autograft, morselized	4		10		9
allograft, blocks > 2 cm or slices	2		3		10
auto- and allograft	1		0		3

^a Control and group 1 were matched for all the variables listed.

^b Chi-square test.

^c In group 2, one patient died prior to reimplantation (see also complications, Table 4).

^d Mann-Whitney U-test.

Table 3. Infectiological, functional, and radiographic outcome, and number of revisions

	Control	p-value	Group 1	p-value	Group 2
Infectiological outcome				0.5 ^a
total hip arthroplasties	22		22		50
cured	–	–	19		46
probably cured	–	–	2		1
relapse of infection with same pathogen	–	–	0		1
reinfection with different pathogen	0	0.2 ^b	1		0
unknown	–	–	0		2
Functional outcome at 2-year follow-up
total hip arthroplasty ^c	22		19		43
mean HHS (SD)	85 (16)	0.9 ^d	84 (17)	0.3 ^d	80 (18)
mean HHS with/without spacer	–	–	–	–	80/78
limping		0.5 ^a		0.5 ^a
none or slight	19		15		30
moderate or severe	3		4		13
walking		0.2 ^a		0.5 ^a
without support	15		9		18
with one cane/crutch	7		8		13
with two canes/crutches	0		2		11
unable to walk/use of wheelchair	0		0		1
Radiographic outcome at last follow-up ^e
total hip arthroplasties	22		20 ^f		47 ^f
mean follow-up in years (SD)	4.8 (2.8)	0.05 ^d	3.3 (2.4)	0.5 ^d	4.0 (3.7)
definitive loosening of stem (revised)	1 (1)	0.5 ^b	2 (2)	0.9 ^b	4 (2)
definitive loosening of cup (revised)	1 (0)	0.2 ^b	0	0.1 ^b	3 (1)
stem subsidence > 5 mm (revised)	0	–	0	0.6 ^b	2 (0)

^a Mann-Whitney U-test.

^b Chi-square test.

^c Only hips with an event-free survival for ≥ 2 years were included in functional outcome analyses.

^d Student t-test.

^e Statistical analysis was performed with endpoints definitive component loosening and stem subsidence > 5 mm.

^f For 2 hips, in group 1 and group 2, radiographs were not available since the patients died prior to the follow-up examinations. Also, postoperative radiographs were not available for another hip in group 2.

Table 4. Number of complications associated with the index operation

	Control	p-value	Group 1	p-value	Group 2
Total hip arthroplasties	22 (22)		22 (21)		50 (48)
Surgical complications
fracture, greater trochanter	3		1		1
fracture/fissure, proximal femur	1		3		2
Post-surgical complications
requiring reoperation
hematoma	2		1		17
wound infection	0		0		1
pin tract infection	–		–		1
requiring closed reduction
dislocation of spacer	–		–		1
dislocation of hip	0		0		6
total reinterventions	2	0.5 ^a	1	0.004 ^a	26
Total (post-) surgical complications	6	0.9 ^a	5	0.03 ^a	29
Non-surgical complications
during hospitalization
thrombosis/emboli	0		0		2
miscellaneous	1		3		4
early death	0		0		2 ^b

^a Mann-Whitney U-test.

^b Death due to heart failure and pneumonia, one month after the index operation.