Low revision rate after total hip arthroplasty in patients with pediatric hip diseases

Figures & data

Table 1. Numbers of primary THAs and diagnoses (percentage, mean age, and percentage of females) in Denmark, Norway, Sweden, and altogether, for the period 1995–2009

	Denmark n = 94,252			Norway n = 90,686			Sweden n = 185,692			Total n = 370,630
Diagnosis	%	Age (years)	Female (%)	%	Age (years)	Female (%)	%	Age (years)	Female (%)	%	Age (years)	Female (%)
Primary OA	78.1	68.8	56.3	73.6	70.9	69.0	79.8	68.8	57.0	77.8	69.3	59.6
Pediatric hip dis.	3.1	51.9	58.6	8.8	57.0	68.0	1.9	53.4	65.5	3.9	55.1	65.5
DDH	2.1	52.9	71.2	7.5	58.0	75.3	1.8	53.8	67.4	3.3	56.0	72.5
Perthes’	0.6	49.5	29.3	–	–	–	0.1	47.2	38.2	0.2	48.9	31.6
SCFE	0.4	49.3	32.4	–	–	–	0.02	53.0	38.2	0.1	49.7	32.9
SCFE/Perthes’	–	–	–	1.3	51.6	27.1	–		–	0.3	51.6	27.1
Other	18.8	68.0	65.4	17.6	69.3	70.2	18.4	71.5	71.8	18.3	70.0	69.7
All	100	68.2	58.1	100	69.4	69.1	100	69.0	59.9	100	68.9	61.7

Figure 1. Type of fixation of the prostheses in patients operated due to osteoarthritis of the hip (OA) (n = 288,435 THAs) and due to pediatric hip disease (n = 14,403 THAs). The patients with pediatric hip disease were younger than the OA patients

Figure 2. Unadjusted survival curves in the Cox model (Kaplan-Meier curves) with any reason for revision as endpoint in the analysis, for THAs after pediatric hip disease and for THAs due to primary osteoarthritis. The two groups were not comparable, however, due to differences in age, sex, and type of fixation. (The numbers of hips at risk at 14 years were 5,885 for OA and 429 for pediatric hip disease).

Figure 3. Survival curves with adjustment for age, sex, and type of fixation in the Cox model with any reason for revision as endpoint in the analysis, for THAs after pediatric hip disease and for THAs due to primary osteoarthritis. The numbers of hips at risk at 14 years were 5,885 for OA and 429 for pediatric hip disease.

Table 2. Results for primary THAs after pediatric hip disease and after primary osteoarthritis. Adjusted for age, sex, and type of fixation in the Cox model, with endpoints as indicated

Endpoint in the analysis	No. of THAs	No. of revisions	10–year survival ^a	RR ^b	95% CI ^c	p–value
Any reason for revision	302,838	12,067
Pediatric hip disease	14,403	853	93.6%	1.04	0.96–1.12	0.4
Primary osteoarthritis	288 435	11,214	93.8%	1	–	–
Aseptic loosening	302 838	5,803
Pediatric hip disease	14,403	396	97.2%	1.00	0.89–1.11	1.0
Primary osteoarthritis	288 435	5,407	97.0%	1	–	–
Dislocation	302 838	2,641
Pediatric hip disease	14,403	156	98.7%	1.10	0.92–1.31	0.3
Primary osteoarthritis	288 435	2,485	98.8%	1	–	–
–
Infection	302 838	1,806
Pediatric hip disease	14,403	72	99.3%	0.86	0.67–1.10	0.2
Primary osteoarthritis	288 435	1,734	99.3%	1	–	–

^a Cox–adjusted 10–year survival.

^b Cox relative revision risk.

^c 95% confidence interval for RR.

Table 3. Results for the first 6 postoperative months for primary THAs after pediatric hip disease and after primary osteoarthritis a

Endpoint in the analysis	No. of THAs	No. of revisions	RR	95% CI	p–value
Any reason for revision	302,838	2,289
Pediatric hip diseases	14,403	141	1.24	1.03–1.50	0.02
Primary osteoarthritis	288 435	2,148	1	–	–
Aseptic loosening	302 838	154
Pediatric hip diseases	14,403	9	0.95	0.46–1.95	0.9
Primary osteoarthritis	288 435	145	1	–	–
Dislocation	302 838	1,020
Pediatric hip diseases	14,403	78	1.78	1.38–2.30	< 0.001
Primary osteoarthritis	288 435	942	1	–	–
Infection	302 838	637
Pediatric hip diseases	14,403	17	0.73	0.44–1.20	0.2
Primary osteoarthritis	288 435	620	1	–	–

^a For full explanation, see Table 2.

Figure 4. Survival in the first six months postoperatively with adjustment for age, sex, and type of fixation in the Cox model with any reason for revision as endpoint in the analysis, for THAs after pediatric hip disease and for THAs due primary osteoarthritis.

Table 4. Results for primary THAs after previous DDH and after primary osteoarthritis

Endpoint in the analysis	No. of THAs	No. of revisions	10–year survival ^a	RR ^b	95% CI ^c	p–value
Any reason for revision	300,503	11,922
DDH	12,068	706	93.3%	1.09	1.00–1.18	0.04
Primary osteoarthritis	288 435	11,214	93.8%	1	–	–
Aseptic loosening	300 503	5,803
DDH	12,068	325	97.1%	1.05	0.93–1.18	0.5
Primary osteoarthritis	288 435	5,407	97.0%	1	–	–
Dislocation	300 503	2,641
DDH	12,068	138	98.7%	1.18	0.98–1.42	0.08
Primary osteoarthritis	288 435	2,485	98.8%	1	–	–
Infection	300 503	1,806
DDH	12,068	57	99.5%	0.85	0.65–1.12	0.3
Primary osteoarthritis	288 435	1,734	99.3%	1	–	–

For full explanation, see Table 2.