Prosthesis survival after total hip arthroplasty—does surgical approach matter? Analysis of 19,304 Charnley and 6,002 Exeter primary total hip arthroplasties reported to the Norwegian Arthroplasty Register

Figures & data

Figure 1. Details of the selection procedure used for THAs registered in the Norwegian Arthroplasty Register between 1987 and 2004. ^aDysplasia with high dislocation and sequela after hip fracture. ^bFor Exeter other head size than 26, 28, and 30 mm.

Figure 2. Distribution of surgical approaches used for Charnley and Exeter THA in 1987–2004.

Table 1.  Details of 19,304 Charnley and

	Lateral without TO^a	Charnley THA		Total	Lateral without TO	Exeter THA	Total
		Lateral without TO^a	Posterolateral			Posterolateral
THA (1987–2004)	15,400	2,321	1,583	19,304	981	5,021	6,002
THA (1987–1994)	4,013	1,422	885	6,320
THA (1995–2004)	11,387	899	698	12,984
No. of hospitals (1987–2004)	54	36	32	57	17	22	26
Females (%)	72	69	68	71	70	70	70
Median age (years)	73	72	72	72	73	71	71
Range	(17–95)	(22–94)	(42–92)	(17–95)	(27–91)	(25–93)	(25–93)
Diagnoses of O.A. (%)	90	90	93	90.0	86	88	88
Systemic antibiotics (%)	98	99	97	98	100	100	100
Antibiotic-containing cement (%)	84	91	66	84	86	51	57
Palacos/Simplex
cement (%)	84 / 16	91 / 9	63 / 37	83 / 17	87 / 13	54 / 46	59 / 41
Median follow-up (years)	5.4	9.1	8.9	6.0	2.2	6.3	5.6
(95 CI)	(5.3–5.5)	(8.8–9.4)	(8.6–9.2)	(5.9–6.1)	(2.1–2.3)	(6.1–6.5)	(5.4–5.8)

^a TO: trochanteric osteotomy.

Figure 3. Survival curves based on Cox multiple regression (by surgical approach) based on 19,304 Charnley THAs and 6,002 Exeter THAs performed between 1987 and 2004, with all revisions as endpoint. A. Charnley THA; B. Exeter THA

Table 2.  Relative revision risk (RR) based on Cox regression analysis with adjustment for confounders, for 19,304 Charnley and 6,002 Exeter THAs operated between 1987 and 2004

Reason for revision	Approach	No. of revisions	Charnley THA			95% CI	p	No. of revisions	Exeter THA			95% CI	p
			Estimated rev. %		RR				Estimated rev. %		RR
			7 years	15 years					7 years	15 years
Any cause of revision
	Lateral –TO ^a	624	3.4	10.3	1			23	4.2	6.4	1
	Posterolateral	98	4.7	8.8	1.1	0.8–1.4	0.6	197	3.5	8.7	0.9	0.5–1.4	0.5
	Lateral +TO ^b	98	2.8	6.6	0.6	0.5–0.8	< 0.01
Infection
	Lateral –TO	91	0.6	0.8	1			5	0.5	0.6	1
	Posterolateral	6	0.2	0.5	0.6	0.2–1.4	0.2	23	0.4	0.5	0.5	0.1–1.8	0.3
	Lateral +TO	10	0.3	0.8	0.6	0.3–1.2	0.2
Dislocation
	Lateral –TO	99	0.8	1.2	1			8	1.9	1.9 c	1
	Posterolateral	21	1.1	2.1	1.9	1.1–3.2	0.02	43	0.8	1.6	0.6	0.2–1.6	0.4
	Lateral +TO	5	0.1	0.4	0.2	0.1–0.6	< 0.01
Aseptic loosening
	Lateral –TO	410	2.5	7.6	1			9	1.8	3.7	1
	Posterolateral	65	2.9	6.0	1.0	0.7–1.3	1.0	115	1.7	5.6	0.7	0.4–1.6	0.5
	Lateral +TO	82	2.2	5.1	0.7	0.6–0.9	0.01
Aseptic loosening of cup
	Lateral –TO	197	1.1	3.8	1
	Posterolateral	42	1.9	3.7	1.4	0.9–2.1	0.09
	Lateral +TO	29	0.5	1.8	0.5	0.3–0.7	0.01
Aseptic loosening of stem
	Lateral –TO	378	2.3	7.1	1
	Posterolateral	56	2.3	5.1	0.9	0.6–1.3	0.5
	Lateral +TO	76	2.1	4.6	0.7	0.6–0.9	0.02

^a– TO: without trochanteric osteotomy.

^b+ TO: with trochanteric osteotomy.

cLast revision at 7 years.

Table 3.  Relative revision risk (RR) estimates based on Cox regression analysis with adjustment for confounders, for Charnley THAs operated in 2 different time periods

Reason for revision	Approach	Charnley THA operated 1987–1994					p	Charnley THA operated 1995–2004				p
		No. of revisions	Estimated rev. %		RR	95% Cl		No. of revisions	Estimated rev. %	RR	95% Cl
			7 years	15 years					7 years
Any cause of revision
	Lateral –TO ^a	315	4.6	11.0	1			309	3.7	1
	Posterolateral	68	5.0	10.0	1.0	0.7–1.4	0.9	30	4.5	1.1	0.8–1.7	0.4
	Lateral +TO ^b	73	2.4	6.4	0.5	0.4–0.7	<0.01	25	4.2	0.9	0.6–1.4	0.7
Infection
	Lateral –TO	30	0.5	0.7	1			61	0.6	1
	Posterolateral	4	0.4	0.5 c	0.8	0.2–2.8	0.7	2	0.2 f	0.5	0.1–1.9	0.3
	Lateral +TO	4	0.1	0.5	0.4	0.1–1.3	0.1	6	0.8 h	1.3	0.5–3.0	0.5
Dislocation
	Lateral –TO	24	0.5	1.1	1			75	0.9	1
	Posterolateral	12	1.0	2.6	2.4	0.9–5.6	0.05	9	2.0	1.9	0.9–3.7	0.08
	Lateral +TO	4	0.1	0.7	0.4	0.1–1.1	0.09	1	0.1 B	0.2	0.02–1.3	0.08
Aseptic loosening
	Lateral –TO	251	3.5	8.9	1			161	2.0	1
	Posterolateral	48	3.5	6.8 e	0.9	0.6–1.3	0.5	17	2.6	1.1	0.7–1.8	0.6
	Lateral +TO	65	2.1	5.7	0.6	0.4–0.8	<0.01	17	2.8	1.1	0.7–1.8	0.7
Aseptic loosening of cup
	Lateral –TO	112	1.2	4.0	1			85	1.1	1
	Posterolateral	31	2.3	3.8 d	1.3	0.8–2.1	0.3	11	1.9	1.5	0.8–2.1	0.2
	Lateral +TO	26	0.5	2.7	0.5	0.3 –0.8	0.02	3	0.5 B	0.4	0.1–1.2	0.9
Aseptic loosening of stem
	Lateral –TO	229	3.3	8.3	1			151	1.8	1
	Posterolateral	44	3.0	6.1 e	0.9	0.6–1.3	0.5	12	2.0	0.8	0.5–1.5	0.6
	Lateral +TO	60	2.1	4.6	0.6	0.4–0.8	<0.01	16	2.7	1.1	0.7–1.8	0.7

^a –TO: without trochanteric osteotomy.

^b +TO: with trochanteric osteotomy.

^c Last revision at 8 years.

^d Last revision at 11 years.

^e Last revision at 13 years.

^f Last revision at 0.5 years.

^g Last revision at 2 years.

^h Last revision at 4 years.

^B Last revision at 5 years.

Figure 4. Survival curves based on Cox multiple regression (by surgical approach) based on primary Charnley THAs, with revision due to aseptic loosening as endpoint. A. 6,320 Charnley THAs performed 1987 through 1994; B. 12,984 Charnley THAs performed 1995 through 2004.

Figure 5. Survival curves based on Cox multiple regression (by surgical approach) based on 19,304 Charnley THAs performed between 1987 and 2004, with revision due to dislocation as endpoint and with a time-period analysis.