Clinical outcome after undisplaced femoral neck fractures

Figures & data

Figure 1. Flow chart of patients.

Table 1. Baseline characteristics of patients

	Undisplaced fracture	Displaced fracture	Displaced fracture	p-value
	Internal fixation	Internal fixation	Hemiarthroplasty
Total number	4,468	3,389	6,900
Mean age [SD], years (95% CI)	81 [8.4]	81 [8.9]	83 (7.0)	< 0.001^a
	(81–81)	(81–81)	(83–83)
Women (%)	3,111 (80)	2,308 (68)	5,221 (76)	< 0.001 ^b
ASA class (%)
ASA 1	457 (10)	301 (8.9)	364 (5.3)
ASA 2	1,705 (38)	1,126 (33)	2,418 (35)
ASA 3	2,013 (45)	1,610 (48)	3,613 (52)
ASA 4	219 (4.9)	296 (8.7)	387 (5.6)
ASA 5	3 (0.1)	14 (0.4)	3 (0.1)
Missing	71 (1.6)	42 (1.2)	115 (1.7)	< 0.001 ^b
Cognitive impairment (%)	1,082 (24)	941 (28)	1,741 (25)	0.002 ^b
Preop. EQ-5D score [SD] (95% CI)	0.64 [0.03]	0.62 [0.03]	0.64 [0.03]	0.2 ^c
	(0.59–0.70)	(0.57–0.68)	(0.58–0.69)

^a ANOVA.

^b Pearson chi-square test.

^c GLM with adjustment for age, sex, comorbidity (ASA classification), and cognitive function.

Table 3. Type of reoperation

Type of reoperation	Undisplaced fracture	Displaced fracture	Displaced fracture
	Internal fixation	Internal fixation	Hemiarthroplasty
	n (%) ^a	n (%) ^a	n (%) ^a
Total hip arthroplasty^b	108 (25)	150 (26)	10 (4.7)
Bipolar hemiarthroplasty	263 (60)	337 (57)	14 (6.6)
Unipolar hemiarthroplasty	2 (0.5)	16 (2.7)
Removal of implant	15 (3.4)	44 (7.5)	1 (0.5)
Re-osteosynthesis	27 (6.2)	17 (2.9)
Girdlestone procedure	10 (2.3)	21 (3.6)	16 (7.5)
Drainage of hematoma or infection	11 (2.5)	2 (0.3)	93 (44)^c
Open reduction of dislocated hemiarthroplasty			26 (12)^d
Closed reduction of dislocated hemiarthroplasty			12 (5.7)
Other		1 (0.2)	40 (19)
Total no. of reoperations	436 (9.8)^e	588 (17)^e	212 (3.1)^e

^a Percentage of reoperated hips.

^b Reported to the Norwegian Arthroplasty Register.

^c Procedure included change of bipolar head in 48 patients.

^d Procedure included change of bipolar head in 14 patients.

^e Percentage of primary-operated hips.

Figure 2. Adjusted survival of implants for the different treatment groups (n = 14,757).

Table 4. Comparison of patient-assessed outcomes in patients according to type of fracture and treatment. Intention-to-treat-analysis. Values are mean (95% CI) [SD]

	Undisplaced fracture	Displaced fracture	p-value ^a	Displaced fracture	p-value ^a
	Internal fixation	Internal fixation	GLM	Hemiarthroplasty	GLM
	(n = 670)	(n = 550)		(n = 778)
Patient satisfaction ^b
At 4 months	26 (19–34) [4.1]	34 (26–42) [4.1]	< 0.001	20 (12–28) [4.1]	< 0.001
At 12 months	29 (20–37) [4.2]	35 (27–44) [4.2]	< 0.001	23 (15–31) [4.2]	< 0.001
Pain ^c
At 4 months	27 (19–35) [3.9]	33 (25–40) [3.8]	< 0.001	19 (12–27) [3.9]	< 0.001
At 12 months	26 (19–34) [3.8]	30 (22–37) [3.8]	0.007	19 (12–26) [3.8]	< 0.001
EQ-5D index score^d
At 4 months (n = 303)	0.50 (0.41–0.59) [(0.04]	0.44 (0.35–0.52) [0.04]	< 0.001	0.53 (0.44–0.62) [0.05]	0.02
At 12 months (n = 292)	0.60 (0.50–0.69) [0.05]	0.55 (0.46–0.64) [0.05]	0.003	0.63 (0.54–0.72) [0.05]	0.02

^a p-value is the probability of no difference between displaced and undisplaced fractures (general linear models (GLMs) adjusted for

differences in age, sex, cognitive impairment, and ASA class between the groups).

^b Patient satisfaction: VAS (visual analog scale); 0 = satisfied and 100 = dissatisfied.

^c Pain: VAS; 0 = no pain and 100 = unbearable pain.

^d EQ-5D index score: 0 = the worst possible health state and 1.0 = full health. EQ-VAS.

Figure 3. Adjusted survival of implants: A. for undisplaced fracture according to age group (n = 4,310); B. for undisplaced fracture according to cognitive function (n = 4,310); C. for undisplaced fracture according to preoperative walking ability (n = 1,175).