Hip prosthesis introduction and early revision risk

Figures & data

Table 1. Descriptive statistics for 39,125 total hip arthroplasty operations in Finland from 1998 to 2007

	N	%
Total no. of operations	39,125	100
Sex
Male	16,849	43.1
Age
< 50 years	1,044	2.7
50–59 years	5,929	15.2
60–69 years	12,991	33.2
70–79 years	15,258	39.0
≥ 80 years	3,903	10.0
Operation
Bilateral	1,373	3.5
Cemented	18,072	46.2
Cementless	14,769	37.7
Hybrid	6,284	16.1
Bone grafts	1,468	3.8
Intravenous prophylactic antibiotics	38,535	98.5
Operations with the 10 most common
stem and cup pairs	22,271	56.9
The 10 most common stem and cup pairs
1 Exeter Universal / Contemporary	5,925	15.1
2 Spectron EF / Reflection All-Poly	2,868	7.3
3 Exeter Universal / Exeter All-Poly	2,838	7.3
4 Biomet Collarless / Biomet Vision	2,210	5.6
5 Link Lubinus SP II / Link IP Acetabular Cups	1,712	4.4
6 ABG II / ABG II	1,617	4.1
7 ABG HA / ABG II	1,436	3.7
8 Link Lubinus SP II / Link Lubinus Eccentric	1,430	3.7
9 Biomet Collarless / Recap (Biomet)	1,284	3.3
10 Biomet Collarless / M2A 38 Flared Acetabular Cup	951	2.4

Table 2. Descriptions of the hospital-level variables in a study of endoprosthesis implementation in Finland for 39,125 THA operations

Proportion of arthroplasty operations in hospital that were THAs, mean (SD)	0.58	(0.10)
Proportion of all operations in hospital that were arthroplasty, mean (SD)	0.13	(0.21)
Femur models per 100 THAs in hospital, mean (SD)	5.51	(4.74)
Hospital’s annual arthroplasty volume, n (%)
< 51 operations	2,135	(5.5)
51–150 operations	9,999	25.6)
151–300 operations	8,814	(22.5)
> 300 operations	18,177	(46.5)

Table 3. Estimated hazard ratios for revision over 3 years after primary THA in a population-based study of 39,125 operations

Ordinal number group Operation	No. of operations	No. of revisions	Unadjusted HR (95% CI)	Age- and sex-adjusted HR (95% CI)
Minimum of stem and cup order numbers
1–15	5,967	228	1.3 (1.1–1.6)	1.3 (1.1–1.5)
16–30	3,980	123	1.1 (0.9–1.3)	1.1 (0.9–1.3)
31–50	4,185	135	1.1 (0.9–1.3)	1.1 (0.9–1.3)
51–100	6,820	220	1.1 (1.0–1.3)	1.1 (1.0–1.3)
101–	18,173	527	1.0	1.0
Maximum of stem and cup order numbers
1–15	2,428	89	1.2 (1.0–1.5)	1.2 (1.0–1.5)
16–30	1,868	59	1.1 (0.8–1.4)	1.0 (0.8–1.4)
31–50	2,264	86	1.3 (1.0–1.6)	1.2 (1.0–1.5)
51–100	4,226	153	1.2 (1.0–1.4)	1.2 (1.0–1.4)
101–	28,339	846	1.0	1.0
Stem and cup order number separately in the same model
Stem
1–15	3,653	141	1.3 (1.1–1.5)	1.1 (0.9–1.4)
16–30	2,536	76	1.0 (0.8–1.3)	0.9 (0.7–1.2)
31–50	2,740	93	1.1 (0.9–1.4)	1.0 (0.8–1.3)
51–100	4,707	162	1.1 (1.0–1.3)	1.1 (0.9–1.3)
101–	25,489	761	1.0	1.0
Cup
1–15	4,742	176	1.3 (1.1–1.5)	1.2 (1.0–1.4)
16–30	3,312	106	1.1 (0.9–1.4)	1.1 (0.9–1.4)
31–50	3,709	128	1.2 (1.0–1.4)	1.1 (0.9–1.4)
51–100	6,339	211	1.2 (1.0–1.4)	1.1 (1.0–1.3)
101–	21,023	612	1.0	1.0

Table 4. Number of operations in stages of introduction for the 10 most common stem and cup pairs

Numbering based on Operation order number	Pair
	1	2	3	4	5	6	7	8	9	10
No. of operations	5,925	2,868	2,838	2,210	1,712	1,617	1,436	1,430	1,284	951
No. of early revisions	153	60	90	81	59	60	38	37	38	26
No. of hospitals	53	34	31	45	18	33	34	25	35	24
Combined (minimum)
1–15	404 ^a	347 ^a	125	367 ^a	38	299 ^a	172 ^a	50	200 ^a	249 ^a
16–30	387 ^a	277 ^a	48	266 ^a	27	228 ^a	165 ^a	34	181 ^a	167 ^a
31–50	478 ^a	286 ^a	101	335 ^a	35	220 ^a	224 ^a	92	198 ^a	160 ^a
51–100	865 ^a	471 ^a	324	443 ^a	89	410 ^a	428 ^a	262	271 ^a	258 ^a
101–	3,791 ^a	1,487 ^a	2,240	799 ^a	1,523	460 ^a	447 ^a	992	434 ^a	117 ^a
Combined (maximum)
1–15	227 ^a	320 ^a	86	54	33	82	117 ^a	29	17	144
16–30	227 ^a	255 ^a	57	38	29	50	122 ^a	16	38	59
31–50	314 ^a	266 ^a	85	85	35	61	126 ^a	28	51	68
51–100	624 ^a	463 ^a	250	145	87	198	360 ^a	13	77	102
101–	4,533 ^a	1,564 ^a	2,360	1,888	1,528	1,226	711 ^a	1,344	1,101	316
Stem
1–15	233 ^a	323 ^a	87	65	34	298 ^a	151 ^a	29	17	25
16–30	231 ^a	259 ^a	56	46	29	228 ^a	117 ^a	16	38	23
31–50	311 ^a	276 ^a	85	99	35	214 ^a	135 ^a	28	51	26
51–100	634 ^a	472 ^a	251	159	89	412 ^a	353 ^a	37	81	59
101–	4,516 ^a	1,538 ^a	2,359	1,841	1,525	465 ^a	680 ^a	1,320	1,097	818
Cup
1–15	398 ^a	344 ^a	124	356 ^a	37	83	138 ^a	50	200 ^a	249 ^a
16–30	383 ^a	273 ^a	49	258 ^a	27	50	170 ^a	34	181 ^a	167 ^a
31–50	481 ^a	276 ^a	101	321 ^a	35	67	215 ^a	92	198 ^a	160 ^a
51–100	855 ^a	462 ^a	323	429 ^a	87	196	435 ^a	238	267 ^a	258 ^a
101–	3,808 ^a	1,513 ^a	2,241	846 ^a	1,526	1,221	478 ^a	1,016	438 ^a	117 ^a

^a The order-numbering groups that were subject to hazard ratio analysis.

Table 5. Pair-specific age- and sex-adjusted hazard ratios for stages of implant introduction a

A	B	C	D	E	F
1	1–15	2.5 (1.5–4.1)	1.2 (0.5–2.7)	1.1 (0.5–2.6)	2.6 (1.6–4.2)
	16–30	2.2 (1.3–3.7)	1.7 (0.9–3.3)	1.7 (0.8–3.3)	2.3 (1.4–3.8)
	31–50	1.7 (1.0–2.8)	2.1 (1.2–3.5)	2.2 (1.3–3.7)	1.5 (0.9–2.7)
	51–100	1.5 (0.9–2.3)	1.4 (0.9–2.3)	1.3 (0.8–2.2)	1.5 (1.0–2.4)
	100–	1.0	1.0	1.0	1.0
2	1–15	1.9 (0.9–3.7)	2.1 (1.1–4.2)	2.1 (1.0–4.1)	1.9 (1.0–3.8)
	16–30	1.0 (0.4–2.7)	1.2 (0.5–3.1)	1.1 (0.4–3.0)	1.1 (0.4–2.8)
	31–50	1.2 (0.5–2.8)	1.1 (0.4–2.8)	1.0 (0.4–2.7)	1.2 (0.5–3.0)
	51–100	1.4 (0.7–2.9)	1.7 (0.9–3.3)	1.6 (0.8–3.1)	1.5 (0.8–3.0)
	100–	1.0	1.0	1.0	1.0
4	1–15	0.7 (0.4–1.4)			0.7 (0.4–1.4)
	16–30	0.6 (0.3–1.4)			0.6 (0.3–1.5)
	31–50	0.7 (0.4–1.5)			0.6 (0.3–1.3)
	51–100	0.8 (0.4–1.4)			0.8 (0.5–1.5)
	100–	1.0			1.0
6	1–15	0.9 (0.5–1.9)		0.8 (0.4–1.7)
	16–30	0.7 (0.3–1.6)		0.7 (0.3–1.5)
	31–50	0.5 (0.2–1.2)		0.3 (0.1–0.9)
	51–100	0.7 (0.4–1.4)		0.8 (0.4–1.5)
	100–	1.0		1.0
7	1–15	2.0 (0.8–5.4)	2.5 (1.0–6.7)	2.7 (1.1–6.5)	1.9 (0.7–5.2)
	16–30	1.3 (0.4–3.8)	1.2 (0.3–4.1)	1.2 (0.3–4.3)	1.2 (0.4–3.5)
	31–50	1.4 (0.5–3.8)	1.1 (0.3–4.0)	0.7 (0.2–3.2)	1.6 (0.6–4.2)
	51–100	1.1 (0.4–2.7)	1.9 (0.9–4.1)	2.0 (0.9–4.4)	1.0 (0.4–2.4)
	100–	1.0	1.0	1.0	1.0
9	1–15	1.7 (0.7–4.0)			1.7 (0.7–4.0
	16–30	1.5 (0.6–3.8)			1.5 (0.6–3.8)
	31–50	1.2 (0.5–3.1)			1.2 (0.5–3.1)
	51–100	0.7 (0.2–1.9)			0.7 (0.2–1.9)
	100–	1.0			1.0
10	1–15	0.5 (0.2–1.5)			0.5 (0.2–1.5)
	16–30	0.9 (0.3–2.4)			0.9 (0.3–2.4)
	31–50	0.7 (0.3–2.1)			0.7 (0.3–2.1)
	51–100	0.9 (0.3–2.1)			0.9 (0.3–2.1)
	100–	1.0			1.0

^a Due to small number of observations in all numbering groups, the pairs 3, 5, and 8 have been excluded from the pairwise analysis.

A Pair

B Order no. of the operation

C Order numbering, minimum, HR (95% CI)

D Order numbering, maximum, HR (95% CI)

E Order numbering, stem, HR (95% CI)

F Order numbering, cup, HR (95% CI)

The smoothed hazard function for revision after primary THA during the follow-up in a population-based study of 39,125 THAs.