Good outcome of total hip replacement in patients with cerebral palsy

Figures & data

Figure 1. Implants by fixation. A. All ages. B. Age < 55 years. C. Age ≥ 55 years.

Table 1. Bearing surface used for the primary implants in the CP and control cohorts

Fixation Bearing surface	Cerebral palsy Number (%)	Control^a Number (%)
Cemented, all	72 (18)	166,654 (39)
MoP	57 (15)	147,807 (35)
MoM	1 (0.3)	871 (0.2)
CoP	9 (2.3)	13,548 (3.2)
Other/unsure	5 (1.2)	4,428 (1.0)
Uncemented, all	163 (42)	161,539 (38)
MoP	26 (6.7)	61,867 (15)
MoM	34 (8.7)	20,833 (4.9)
CoP	31 (8.0)	22,283 (5.2)
CoC	66 (17)	51,413 (12)
CoM	2 (0.5)	1,566 (0.3)
Other/unsure	4 (1.0)	3,577 (0.8)
Hybrid, all	85 (22)	64,701 (15)
MoP	50 (13)	43,463 (10)
MoM	5 (1.3)	1,606 (0.4)
CoP	9 (2.3)	6,574 (1.5)
CoC	17 (4.4)	11,530 (2.7)
Other/unsure	4 (1.0)	1,528 (0.4)
Reverse hybrid, all	14 (3.6)	10,358 (2.5)
MoP	7 (1.8)	7,086 (1.6)
CoP	7 (1.8)	3,202 (0.8)
Other/unsure	0	70 (0.1)
Resurfacing, all MoM	55 (14)	22,531 (5.3)
Total	389 (100)	425,783 a (100)

a Implant type was uncertain for 30 of the control group.

Figure 2. Cumulative probability of revision (Kaplan-Meier, with pointwise 95% CIs) for CP vs. control patients.

Table 2. Cumulative percentage revised (Kaplan-Meier) for CP and control patients at 1, 3, and 5 years after primary operation, for all cases and by implant type (fixation)

Cohort	n	Female %	Age at primary operation median (IQR)	Cumulative percentage probability of revision (95%CI) at:
				1 year	3 years	5 years
All cases
CP	389	58.6	53 (40–64)	2.6 (1.4–4.8)	4.7 (2.9–7.6)	6.4 (3.8–11)
Control	425,813^a	60.2	59 (61–76)	0.79 (0.76–0.82)	1.8 (1.7–1.8)	2.9 (2.9–3.0)
Cemented
CP	72	61.1	62 (55–69)	1.5 (0.21–10)	1.5 (0.21–10)	1.5 (0.21–10)
Control	166,654	66.2	73 (68–79)	0.47 (0.44–0.51)	1.1 (1.1–1.2)	1.7 (1.6–1.8)
Uncemented
CP	163	54.0	50 (41–63)	1.9 (0.63–5.9)	7.1 (3.7–13)	7.1 (3.7–13)
Control	161,539	56.6	65 (58–72)	1.0 (0.99–1.1)	2.3 (2.3–2.4)	3.8 (3.7–4.0)
Hybrid
CP	85	67.1	53 (44–64)	1.2 (0.17–8.1)	1.2 (0.17–8.1)	1.2 (0.17–8.1)
Control	64,701	62.9	69 (62–76)	0.73 (0.66–0.80)	1.4 (1.3–1.5)	2.1 (2.0–2.3)
Reverse hybrid
CP	14	78.6	59 (48–63)	7.1 (1.0–41)	7.1 (1.0–41)	54 (12–99)
Control	10,358	65.2	71 (65–77)	0.81 (0.70–1.0)	1.6 (1.4–2.0)	2.4 (2.0–2.8)
Resurfacing
CP	55	50.9	36 (19–52)	7.3 (2.8–18)	7.3 (2.8–18)	12 (4.6–27)
Control	22,531	31.7	54 (48–60)	1.4 (1.3–1.6)	3.8 (3.5–4.0)	7.1 (6.7–7.5)

a Includes the 30 with uncertain hip fixation

Table 3. Comparison of the EQ-5D health scale, EQ-5D index, and Oxford hip score (OHS) in CP patients and controls, before primary hip replacement and 6 months postoperatively

	CP		Controls		p-value^b
	Median (IQR)	n	Median (IQR)	n
Oxford hip score (OHS)
Pre-operation (Q1): all cases	12 (7–18)	89	17 (11–23)	122,891	< 0.001
Pre-operation (Q1): complete pairs^a	13 (7–18)	47	18 (12–24)	92,073
6 months after operation (Q2): complete pairs	34 (29–41)	47	41 (34–46)	92,073	< 0.001
Improvement (Q2–Q1)	23 (14–28)	47	21 (14–28)	92,073	0.8
EQ-5D health scale
Pre-operation (Q1): all cases	60 (40–80)	80	70 (50–80)	111,808	0.04
Pre-operation (Q1): complete pairs	60 (40–75)	43	70 (50–80)	80,341
6 months after operation (Q2): complete pairs	70 (60–80)	43	80 (69–90)	80,341	0.005
Improvement (Q2–Q1)	10 (−5 to 25)	43	9 (−2 to 20)	80,341	0.9
EQ-5D index
Pre-operation (Q1): all cases	0.12 (−0.02 to 0.59)	72	0.52 (0.03–0.62)	116,713	0.002
Pre-operation (Q1): complete pairs	0.11 (−0.02 to 0.59)	38	0.52 (0.06–0.66)	83,151
6 months after operation (Q2): complete pairs	0.67 (0.52–0.78)	38	0.80 (0.69–1.0)	83,151	< 0.001
Improvement (Q2–Q1)	0.38 (0.11–0.69)	38	0.38 (0.18–0.69)	83,151	0.6

a ” Complete pairs” were the cases where both Q1 and Q2 results were available.

b Groups compared by Mann-Whitney U-test.