Higher risk of reoperation for bipolar and uncemented hemiarthroplasty

Figures & data

Table 1. Number of procedures (%) performed on patients in the different age groups

	Female	Male	Total
Age group
< 75 years	1,298 (8)	784 (12)	2,082 (9)
75–85 years	7,920 (47)	3,266 (48)	11,186 (48)
> 85 years	7,539 (45)	2,702 (40)	10,241 (44)
Total	16,757	6,752	23,509

Table 2. The most common stems and implant heads in the different groups

	n (%)
Stem ^a
Cemented (n = 22,785)
Polished surface (n = 8,965)
Exeter polished	6,771 (76)
CPT (CoCr)	1,550 (17)
MS30 polished	616 (7)
Various other designs	28 (0.3)
Matte surface (n = 13,820)
Lubinus SPII	10,816 (78)
Spectron EF Primary	1,358 (10)
Covision straight	684 (5)
Various other designs	962 (7)
Uncemented (n = 724)
Corail collarless	499 (69)
Bi-Metric Fracture Stem	129 (18)
Corail collar	28 (4)
Various other designs	43 (6)
Implant head ^b
Unipolar (n = 11,177)
Mega Caput	5,003 (45)
V40 Unipolar	2,922 (26)
Unipolar head	1,418 (13)
Various other designs	1,834 (16)
Bipolar (n = 12,332)
Vario Cup	5,939 (48)
UHR Universal Head	3,805 (31)
Ultima Monk	2,107 (17)
Various other designs	481 (4)

^a Corail collarless: Depuy, Leeds, UK; Bi-Metric Fracture Stem: Biomet Orthopedics, Warsaw, IN; Corail collar: Depuy; Exeter polished: Stryker, Kalamazoo, MI; CPT (CoCr): Zimmer, Warsaw, IN; MS30 polished: Zimmer, Winterthur, Switzerland; Lubinus SP II: Waldemar Link, Hamburg, Germany; Spectron EF Primary: Smith & Nephew Orthopaedics, Memphis, TN; Covision straight: Covision Medical Technologies, Carlton in Lindrick, UK.

^bMega Caput: Waldemar Link; V40 Unipolar: Stryker; Unipolar Head: Smith & Nephew Orthopaedics; Vario Cup: Waldemar Link; UHR Universal Head: Stryker; Ultima Monk: Zimmer, Warsaw, IN.

Table 3. ASA grade and classification of cognitive impairment 2008–2010 (number of procedures (%))

	Female	p-value ^c	Male	Total
ASA grade ^a
1	233 (3)	0.01	69 (2)	302 (3)
2	3,376 (43)	< 0.001	1,079 (33)	4,455 (40)
3	3,836 (49)	< 0.001	1,898 (58)	5,734 (52)
4	387 (5)	< 0.001	229 (7)	616 (6)
5	6 (0.1)	0.1	6 (0.2)	12 (0.1)
Cognitive impairment ^b
None	5,408 (68)	0.8	2,274 (68)	7,682 (68)
Suspected	747 (9)	0.05	355 (11)	1,102 (10)
Evident	1,810 (23)	0.3	735 (22)	2,545 (22)

^a Data available for 11,119 procedures (85.4%).

Missing data for 1,897 procedures (14.6%).

^b Data available for 11,329 procedures (87.0%).

Missing data for 1,687 procedures (13.0%).

^c Chi-square test.

Table 4. Number (%) of reoperations and revisions in different categories

	Reoperation	Revision
Sex
Female (n = 16,757)	606 (3.6)	487 (2.9)
Male (n = 6,752)	282 (4.2)	228 (3.4)
Diagnosis
Acute fracture (n = 22,441)	802 (3.6)	641 (2.9)
Secondary procedure ^a (n = 1,068)	86 (8.1)	74 (6.9)
Age group
< 75 years (n = 2,082)	136 (6.5)	117 (5.6)
75–85 years (n = 11,186)	438 (3.9)	354 (3.2)
> 85 years (n = 10,241)	314 (3.1)	244 (2.4)
Stem type
Uncemented (n = 724)	42 (5.8)	36 (5.0)
Cemented polished (n = 8,965)	345 (3.8)	265 (3.0)
Cemented matte (n = 13,820)	501 (3.6)	414 (3.0)
Implant head
Unipolar (n = 11,177)	347 (3.1)	278 (2.5)
Bipolar (n = 12,332)	541 (4.4)	437 (3.5)
Surgical approach
Hardinge (n = 2,346)	84 (3.6)	61 (2.6)
Gammer (n = 9,740)	337 (3.5)	268 (2.8)
Moore (n = 11,423)	467 (4.1)	386 (3.4)
Whole group	888 (3.8)	715 (3.0)

^a Hemiarthroplasty as secondary procedure after failed internal fixation.

Table 5. Numbers and causes of reoperations and revisions

	Reoperation	Revision
Dislocation	393	373
Infection	275	174
Fracture	131	93
Acetabular erosion	41	41
Pain	17	16
Aseptic loosening	9	9
Other reasons	22	9
Total	888	715

Figure. Proportion not reoperated

Survival analysis (Kaplan-Meier) regarding reoperation for patients treated with unipolar and bipolar hemiarthroplasties, with 95% confidence intervals.

Table 6. Hazard ratios (Cox regression analysis) with 95% CIs for reoperation generally and for specific reasons

	Any reason (n = 888)		Dislocation (n = 393)		Infection (n = 275)		Fracture (n = 131)		Acet. eros.^a (n = 41)
	HR ^b (CI)	p–value	HR ^b (CI)	p–value	HR ^b (CI)	p–value	HR ^b(CI)	p–value	HR ^b (CI)	p–value
Sex
Male	1.22	0.006	1.09	0.4	1.10	0.5	2.15	< 0.001	0.88	0.7
	(1.06–1.41)		(0.88–1.36)		(0.85–1.42)		(1.52–3.05)		(0.43–1.81)
Female ^c	1		1		1		1		1
Diagnosis
Secondary procedure ^d	2.11	<0.001	2.52	<0.001	2.63	<0.001	0.83	0.7	1.46	0.5
	(1.69–2.64)		(1.83–3.48)		(1.82–3.81)		(0.36–1.89)		(0.45–4.75)
Acute fracture ^c	1		1		1		1		1
Age group
Age < 75 years	1.82	<0.001	1.70	0.001	1.76	0.002	1.10	0.8	46.2	<0.001
	(1.48–2.23)		(1.24–2.32)		(1.24–2.51)		(0.62–1.95)		(6.0–355)
Age 75–85 years	1.16	0.05	1.20	0.1	0.95	0.7	0.94	0.7	19.6	0.004
	(1.004–1.34)		(0.97–1.49)		(0.74–1.24)		(0.65–1.36)		(2.7–144)
Age > 85 years ^c	1		1		1		1		1
Type of stem
Uncemented	1.54	0.008	0.92	0.8	1.13	0.7	20.0	<0.001	1.86	0.4
	(1.12–2.13)		(0.52–1.61)		(0.59–2.16)		(9.1–43.8)		(0.43–8.1)
Cemented polished	1.08	0.3	0.65	<0.001	1.04	0.7	13.5	<0.001	0.57	0.2
	(0.94–1.24)		(0.52–0.81)		(0.81–1.34)		(7.4–24.6)		(0.26–1.25)
Cemented matte ^c	1		1		1		1		1
Type of implant head
Bipolar implant head	1.28	0.001	1.42	0.001	1.31	0.04	1.70	0.008	0.30	0.001
	(1.11–1.47)		(1.15–1.76)		(1.01–1.68)		(1.15–2.52)		(0.15–0.61)
Unipolar implant head ^c	1		1		1		1		1
Surgical approach
Anterolateral approach ^e	0.92	0.2	0.72	0.002	0.94	0.6	1.09	0.6	1.58	0.2
	(0.80–1.06)		(0.58–0.89)		(0.73–1.20)		(0.76–1.56)		(0.82–3.02)
Posterior approach ^c	1		1		1		1		1

^a Acetabular erosion.

^b Hazard ratio.

^c Reference.

^d Hemiarthroplasty as secondary procedure after failed internal fixation.

^e The Hardinge and Gammer approaches together, i.e. anterolateral transgluteal approach.

Table 7. Number of patients (%) who had died at 1 year postoperatively and at the end of the study period (n = 22,642)

	1 year	p-value ^a	End of study period	p-value ^a
Female	3,257 (20)	< 0.001	6,485 (40)	< 0.001
Male	2,116 (32)		3,486 (53)
Total	5,373 (24)		9,971 (44)

^a Chi-square test.

Table 8. Hazard ratios (Cox regression analysis) with 95% CI for mortality during the first postoperative year, including patients operated from 2008 through 2010 (valid number of patients in the analysis = 9,679)

	HR ^a (CI)	p-value
Sex
Male	1.78 (1.64–1.94)	< 0.001
Female ^b	1
Implant fixation
Uncemented	1.06 (0.83–1.35)	0.7
Cemented ^b	1
Age group
Age < 75 years	0.50 (0.42–0.60)	< 0.001
Age 75–85 years	0.59 (0.54–0.64)	< 0.001
Age > 85 years ^b	1
ASA grade
1 or 2	0.49 (0.45–0.54)	< 0.001
3, 4, or 5 ^b	1
Cognitive impairment
None	0.56 (0.52–0.61)	< 0.001
Suspected or evident ^b	1

^a Hazard ratio.

^b Reference.