Functional outcome of femoral peri prosthetic fracture and revision hip arthroplasty: A matched‐pair study from the New Zealand Registry

Figures & data

Figure 1. Number of revisions for periprosthetic fracture per year.

Table 1.  Patient demographics

	Periprosthetic fractures (232 hips, 232 patients)	Reference group (232 hips, 232 patientsz)
Females	103 (44%)	103 (44%)
Males	129 (56%)	129 (56%)
Average age	73 years	73 years
Mean time between index and revision surgery	10 years	11 years
6–month OHS response rate	57% (123/215)	76% (175/230)

Figure 2. Overall Oxford hip score (OHS) and outcome according to age and sex. Error bars represent ± SD.

Table 2.  Comparisons of baseline and outcome variables between periprosthetic fracture group and reference group. Point estimate is how much more likely the characteristic or outcome is for cases with periprosthetic fractures relative to the reference group

	Periprosthetic fractures (n = 232)	Reference group (n = 232)	P‐value	Point estimate (95% CI)
Surgical characteristics
Previous revision	27 (11.6%)	32 (13.8%)	0.6	0.8 (0.5–1.5)
Bone graft (femoral)
Total	50 (21.6%)	16 (6.9%)	< 0.001	4.7(2.2–11)
Allograft	40(17.2%)	14(6.0%)	< 0.001	4.3(1.9–11)
Autograft	6 (2.6%)	2 (0.8%)	0.2	5.0 (0.6–23)
Synthetic	4(1.7)	0 (0.0%)	n/a	n/a
Acetabulum revised	118 (51%)	155(67%)	< 0.001	0.52 (0.4–0.8)
Cemented stem	42(18%)	77 (33%)	< 0.001	0.43 (0.3–0.7)
Outcomes
Mean follow‐up period (years)	3.2	3.6
Subsequent re‐revision	17 (7.3%)	6 (2.6%)	0.06	0.52 ^a (0.27–1.0)
Overall deaths	40(17%)	25(11%)	0.06	0.06 ^a (0.004–1.1)
Deaths at < 6 months	17(7.3%)	2 (0.9%)	< 0.001	17(2.7–710)

^a Exponentiated coefficient of the variable “match” in the associated Cox regression analysis (see Methods).

Table 3.  Comparisons of outcome variables (periprosthetic fracture patients only)

	No. of hips	Mean OHS	>Re‐revision rate (n)	Death rate at < 6 months (n)
Total	232	29	17 (7.3%)	17 (7.3%)
Surgeons with > 15 revisions/year^a	61	28	4 (7%)	4 (7%)
< 5 revisions/year	41	29	3 (7%)	7 (17%)
P‐value		0.8	0.9	0.1
Surgeons with > 5 fracture revisions ^b	66	26	5 (8%)	3 (5%)
< 2 fracture revisions	43	30	3 (7%)	8 (19%)
P‐value		0.2	0.9	0.04
Largest 5 centers ^c	85	31	8 (9%)	3 (4%)
Smallest 15 centers	35	28	3 (9%)	7 (20%)
P‐value		0.3	0.9	0.03

^a Mean number of revisions performed for all causes.

^b Total number of revisions performed for periprosthetic fracture.

^c Measured by patient volume.