Reduced dislocation rate after hip arthroplasty for femoral neck fractures when changing from posterolateral to anterolateral approach

Figures & data

Table 1. Data on all hips included in the study

Characteristics	2007(n = 199)	2008(n = 173)	p-value
Age ^a	81 (8)	82 (8)	0.2
Sex ^b
Female	145 (73)	132 (76)	0.5
Male	54 (27)	41 (24)
Weight (kg) ^a	64 (13)	64 (14)	1.0
Height (cm) ^a	168 (8)	166 (9)	0.2
ASA-category ^b			0.3
ASA 1 or 2	106 (53)	80 (36)	0.2
ASA 3 or 4	93 (47)	93 (64)
Cognitive dysfunction ^b
No	156 (78)	132 (68)	0.8
Probable	16 (11)	17 (13)
Certain	27 (11)	24 (19)
Surgical approach ^b
Anterolateral	46 (23)	134 (78)	< 0.001
Posterolateral	153 (77)	39 (22)
Indication^b
Primary	157 (79)	152 (88)	0.02
Secondary	42 (21)	21 (12)
Type of arthroplasty ^b
HA	104 (52)	116 (67)	0.004
Cemented THA	44 (22)	44 (25)
Reversed hybrid THA	51 (26)	13 (8)
Surgeons experience ^b
Consultant	195 (98)	162 (93)	0.03
Registrar	4 (2)	11 (7)

^a mean (SD)

^b n (%)

Table 2. Details on all 19 hips in the study that dislocated

A	B	C	D	E	F	G	H	I	J	K
1	83	F	2	No	2007	1	Primary	Anterolateral	HA	Excision arthroplasty after multiple dislocations
2	84	M	2	No	2007	5	Secondary	Anterolateral	Cemented THA	Excision arthroplasty after multiple dislocations
3	60	M	3	No	2007	3	Secondary	Posterolateral	Reversed hybrid THA	One dislocation, closed reduction
4	67	F	2	No	2007	4	Primary	Posterolateral	Cemented THA	One dislocation, closed reduction
5	73	M	2	No	2007	13	Primary	Posterolateral	Reversed hybrid THA	Constrained cup after multiple dislocations
6	75	M	3	Probable	2007	16	Primary	Posterolateral	HA	Excision arthroplasty after multiple dislocations
7	76	F	3	No	2007	2	Primary	Posterolateral	Cemented THA	Multiple dislocations and closed reductions
8	76	M	2	No	2007	32	Primary	Posterolateral	Reversed hybrid THA	Multiple dislocations and closed reductions
9	77	F	2	No	2007	15	Primary	Posterolateral	Reversed hybrid THA	One dislocation, closed reduction
10	80	F	3	No	2007	1	Primary	Posterolateral	HA	One dislocation, open reduction and stem revision
11	81	F	3	No	2007	1	Primary	Posterolateral	HA	One dislocation, open reduction
12	82	F	3	No	2007	76	Primary	Posterolateral	Cemented THA	One dislocation, closed reduction
13	82	F	2	No	2007	38	Primary	Posterolateral	Reversed hybrid THA	One dislocation, closed reduction
14	83	F	3	No	2007	1	Secondary	Posterolateral	HA	Excision arthroplasty after multiple dislocations
15	84	F	3	No	2007	54	Primary	Posterolateral	HA	One dislocation, closed reduction
16	89	F	3	No	2007	11	Secondary	Posterolateral	Reversed hybrid THA	One dislocation, closed reduction
17	67	F	2	No	2008	70	Primary	Posterolateral	Cemented THA	One dislocation, closed reduction
18	70	F	2	Certain	2008	85	Primary	Posterolateral	Cemented THA	Constrained cup after multiple dislocations
19	88	F	2	Probable	2008	15	Primary	Posterolateral	HA	Multiple dislocations and closed reductions

A No.

B Age

C Sex

D ASA class

E Cognitive dysfunction

F Year

G Time to first dislocation (days)

H Primary or secondary surgery

I Surgical approach

J Type of arthroplasty

K Final outcome

Table 3. Multivariate logistic regression to evaluate factors associated with dislocation

Explanatory	n (372)	Dislocation rate (%)	OR (95% CI)	p-value
Age
≤ 82	194	6.7	1
> 82	178	3.4	0.7 (0.2–1.9)	0.5
Sex
Male	95	5.3	1
Female	277	5.1	1.1 (0.4–3.1)	0.8
ASA-category
ASA 1–2	186	5.4	1
ASA 3–4	186	4.8	1.1 (0.4–3.1)	0.8
Cognitive dysfunction
No	288	5.9	1
Probable	33	3.0	0.7 (0.1–6.2)	0.7
Certain	51	2.0	0.4 (0.1–3.4)	0.4
Indication
Primary	309	4.9	1
Secondary	63	6.3	1.0 (0.3–3.4)	1.0
Type of arthroplasty
HA	220	3.2	1
Cemented THA	88	6.8	1.6 (0.4–5.9)	0.5
Reversed hybrid THA	64	9.4	1.4 (0.4–5.0)	0.6
Surgeon's experience
Consultant	357	5.3	1
Registrar	15	0.0	0.2 (0.0–4.1)	1.0
Surgical approach
Anterolateral	180	1.1	1
Posterolateral	192	8.9	7.6 (1.7–34.8)	0.01

Cox regression cumulative dislocation rate adjusted for sex, age, cognitive function, and type of arthroplasty.

Table 4. Numbers of complications leading to reoperation

Complication	2007 (n = 199)	2008 (n = 173)
Deep infection	5	2
Periprosthetic fracture	3	4
Early aseptic loosening	1	0