Joint kinematics and kinetics during walking and running in 32 patients with hip dysplasia 1 year after periacetabular osteotomy

Figures & data

Figure 1. 32 patients with hip dysplasia were included from March 1, 2011 to December 1, 2011.

Figure 2. Mean values of peak joint angle (degrees) and peak joint moment (N*m/kg) during walking in the sagittal plane as a function of the stance phase (%).

Table 1. Baseline characteristics ^a of patients and controls

	Baseline Controls (n = 32) ^a	Preoperatively Patients (n = 28) ^a	6 months Patients (n = 28) ^a	postoperatively p-value	Preoperatively Patients (n = 29) ^a	12 months postoperatively Patients	postoperatively p-value
HAGOS pain (0–100)	100 (85–100)	50 (20–95)	79 (48–100)	< 0.001	50 (20–95)	78 (20–100)	< 0.001
HAGOS symptoms (0–100)	96 (79–100)	48 (21–96)	68 (25–93)	< 0.001	50 (21–96)	71 (25–93)	< 0.001
HAGOS ADL (0–100)	100 (85–100)	53 (5–100)	85 (35–100)	< 0.001	60 (5–100)	90 (30–100)	< 0.001
HAGOS sport/recreation (0–100)	100 (84–100)	38 (3–91)	70 (16–91)	< 0.001	38 (3–91)	63 (6–100)	< 0.001
HAGOS participation (0–100)	100 (50–100)	25 (0–100)	50 (0–100)	0.05	25 (0–100)	50 (0–100)	0.02
HAGOS quality of life (0–100)	100 (75–100)	38 (0–80)	55 (0–90)	0.001	40 (0–80)	65 (10–100)	< 0.001
VAS score at rest, mm	0 (0–11)	11 (0–71) ^b	0 (0–19) ^b	< 0.001	12 (0–71) ^c	0 (0–41) ^c	0.002
VAS score during walking, mm	0 (0–2)	9 (0–83) ^b	1 (0–21) ^b	0.005	9 (0–83) ^c	0 (0–49) ^c	0.008
VAS score during running, mm	0 (0–8)	19 (0–72 ^b	5 (0–63) ^b	< 0.001	13 (0–72) ^c	3 (0–54) ^c	0.03
Non-prescription analgesia, n	-	5	1	-	5	1	-
Prescription analgesia, n	-	8	3	-	7	3	-

^aBaseline characteristics are presented as median values (range) and as numbers for patients and healthy controls before and after PAO.

^bn = 25.

^cn = 23. Differences between the groups were tested with Wilcoxon signed-rank test.

HAGOS: The Copenhagen hip and groin outcome score; ADL: activities of daily living.

Table 2. Peak joint angles in patients with hip dysplasia and in controls

	Baseline	Baseline	6 months after PAO			Baseline	12 months after PAO
	Controls (n = 32) ^a	Patients (n = 25) ^a	Patients (n = 25) ^a	Difference (CI)	p-value	Patients (n = 23) ^a	Patients (n = 23) ^a	Difference (CI)	p-value
Walk stance phase, s	0.6 (0.0)	0.6 (0.0)	0.6 (0.0)	0.0 (0.0 to 0.0)	1.0	0.6 (0.0)	0.6 (0.0)	0.0 (0.0 to 0.0)	0.8
Walk velocity, m/s	1.4 (0.1)	1.3 (0.2)	1.3 (0.1)	0.0 (-0.1 to 0.0)	0.1	1.3 (0.1)	1.4 (0.1)	0.0 (-0.1 to 0.0)	0.2
Peak joint angles in walking, degrees
Ankle
A1	-9.6 (2.4)	-8.5 (1.9)	-8.8 (2.6)	0.3 (-0.8 to 1.3)	0.6	-8.5 (2.0)	-8.8 (2.5)	0.4 (-0.6 to 1.4)	0.4
A2	7.3 (2.8)	8.6 (3.8)	8.9 (3.5)	-0.3 (-1.5 to 0.9)	0.6	8.7 (3.9)	7.9 (3.9)	0.7 (-0.6 to 2.0)	0.3
Knee
K1	-4.5 (5.1)	-4.7 (3.8)	-4.5 (4.3)	-0.2 (-2.0 to 1.6)	0.8	-5.1 (3.8)	-3.2 (4.7)	-1.8 (-4.0 to 0.4)	0.1
K2	-18 (5.5)	-17 (3.7)	-17 (6.2)	0.1 (-2.4 to 2.6)	1.0	-17 (3.6)	-16 (5.8)	-0.9 (-3.1 to 1.2)	0.4
K3	-3.0 (4.4)	-6.1 (4.2)	-6.7 (5.4) ^b	0.6 (-1.1 to 2.3)	0.5	-6.1 (4.4)	-5.0 (5.6)	-1.0 (-3.2 to 1.1)	0.3
Hip
H1	-13 (4.5)	-10 (4.8)	-9.6 (4.6) ^b	-0.6 (-2.2 to 1.0)	0.4	-11 (3.9)	-12 (4.2)	1.1 (-0.3 to 2.6)	0.1
Run stance phase, s	0.3 (0.0)	0.3 (0.0)	0.3 (0.0) ^b	0.0 (0.0 to 0.0)	0.2	0.3 (0.0)	0.3 (0.0)	0.0 (0.0 to 0.0)	0.5
Run velocity, m/s	2.6 (0.3)	2.4 (0.4)	2.4 (0.3)	0.0 (-0.1 to 0.1)	0.6	2.5 (0.3)	2.4 (0.2)	0.1 (0.0 to 0.2)	0.2
Peak joint angles in running, degrees
Ankle
A1	2.2 (3.8)	1.8 (6.0)	4.1 (3.1) ^b	-2.3 (-4.7 to -0.0)	0.05	2.6 (6.0)	3.7 (4.7)	-1.2 (-2.6 to 0.3)	0.1
A2	21 (3.8)	20 (4.7)	21 (3.5)	-1.2 (-2.7 to 0.3)	0.1	21 (4.4)	21 (3.4)	-0.3 (-1.7 to 1.1)	0.7
Knee
K1	-14 (6.6)	-13 (6.5)	-15 (5.8)	1.7 (-0.9 to 4.4)	0.2	-14 (6.5)	-13 (6.4)	-0.6 (-2.7 to 1.5)	0.5
K2	-42 (5.8)	-39 (8.2)	-40 (6.4)	1.2 (-1.3 to 3.7)	0.3	-41 (6.1)	-40 (5.9)	-0.7 (-2.6 to 1.2)	0.5
K3	-15 (5.6)	-16 (6.8)	-17 (6.4)	0.8 (-1.4 to 3.0)	0.4	-17 (5.4)	-16 (5.5)	-1.3 (-3.1 to 0.6)	0.2
Hip
H1	-5.6 (3.9)	-4.1 (5.6)	-4.3 (4.4)	0.2 (-1.6 to 2.0)	0.8	-5.0 (5.3)	-5.0 (4.0)	0.0 (-2.1 to 2.1)	1.0

^aPeak values are reported as mean values and standard deviation. Differences between the outcomes before and after PAO were tested with paired t-test and are reported as mean differences (95% CI). Differences between patients and healthy controls were tested with unpaired t-test.

^bSignificantly different compared with the healthy controls.

PAO: periacetabular osteotomy; A1: peak plantar flexion in the first half of the stance phase; A2: peak dorsiflexion in the second half of the stance phase; K1: extension at heel strike; K2: peak flexion in the first half of the stance phase; K3: peak extension in the second half of the stance phase; H1: peak extension.

Table 3. Peak joint moments in patients with hip dysplasia and in controls

Peak joint moments, N*m/kg	Baseline	Baseline	6 months after PAO			Baseline	12 months after PAO
	Controls (n = 32) ^a	Patients (n = 25) ^a	Patients (n = 25) ^a	Difference (CI)	p-value	Patients (n = 23) ^a	Patients (n = 23) ^a	Difference (CI)	p-value
In walking
Ankle
MA1	0.20 (0.05)	0.18 (0.05)	0.18 (0.05)	0.00 (-0.02 to 0.02)	0.8	0.18 (0.05)	0.19 (0.09)	-0.01 (-0.04 to 0.03)	0.7
MA2	-1.56 (0.17)	-1.46 (0.13)	-1.51 (0.11)	0.05 (0.02 to 0.09)	0.007	-1.51 (0.11)	-1.48 (0.35)	-0.03 (-0.16 to 0.10)	0.7
Knee
MK1	-0.46 (0.11)	-0.40 (0.14)	-0.45 (0.14)	0.05 (0.01 to 0.09)	0.009	-0.41 (0.11)	-0.47 (0.10)	0.05 (0.01 to 0.10)	0.01
MK2	0.46 (0.19)	0.36 (0.18)	0.28 (0.20) ^b	0.08 (0.02 to 0.15)	0.02	0.37 (0.16)	0.30 (0.16) ^b	0.07 (0.00 to 0.13)	0.04
MK3	-0.54 (0.14)	-0.42 (0.19)	-0.51 (0.19)	0.10 (0.04 to 0.15)	0.002	-0.44 (0.13)	-0.55 (0.15)	0.12 (0.06 to 0.18)	< 0.001
MK4	0.26 (0.13)	0.21 (0.06)	0.29 (0.09)	-0.08 (-0.12 to -0.03)	0.001	0.22 (0.06)	0.34 (0.11) ^b	-0.12 (-0.17 to -0.07)	< 0.001
Hip
MH1	-1.19 (0.20)	-1.05 (0.27)	-1.07 (0.30)	0.02 (-0.06 to 0.11)	0.6	-1.06 (0.21)	-1.09 (0.24)	0.03 (-0.08 to 0.14)	0.5
MH2	0.70 (0.22)	0.57 (0.13)	0.72 (0.18)	-0.15 (-0.24 to -0.06)	0.002	0.59 (0.13)	0.80 (0.22)	-0.22 (-0.32 to 0.11)	< 0.001
In running
Ankle
MA1	0.17 (0.12)	0.16 (0.17)	0.16 (0.07)	0.00 (-0.05 to 0.06)	0.9	0.14 (0.19)	0.13 (0.10)	0.01 (-0.05 to 0.07)	0.7
MA2	-2.32 (0.41)	-2.22 (0.40)	-2.16 (0.33)	-0.06 (-0.17 to 0.05)	0.3	-2.33 (0.44)	-2.33 (0.35)	0.00 (-0.12 to 0.12)	1.0
Knee
MK1	-0.49 (0.18)	-0.47 (0.21)	-0.44 (0.15)	-0.04 (-0.13 to 0.06)	0.4	-0.49 (0.22)	-0.45 (0.14)	-0.04 (-0.12 to 0.04)	0.3
MK2	1.87 (0.42)	1.68 (0.48)	1.48 (0.42) ^b	0.20 (0.02 to 0.37)	0.03	1.70 (0.52)	1.57 (0.41) ^b	0.13 (-0.03 to 0.29)	0.1
MK3	-0.20 (0.15)	-0.24 (0.23)	-0.24 (0.18)	0.00 (-0.10 to 0.09)	1.0	-0.30 (0.34)	-0.23 (0.12)	-0.07 (-0.20 to 0.06)	0.3
MK4	1.58 (0.41)	1.35 (0.46)	1.17 (0.43) ^b	0.17 (0.01 to 0.33)	0.04	1.39 (0.47)	1.25 (0.35) ^b	0.14 (-0.00 to 0.28)	0.06
Hip
MH1	-1.74 (0.42)	-1.49 (0.43)	-1.47 (0.32) ^b	-0.02 (-0.19 to 0.15)	0.8	-1.55 (0.46)	-1.45 (0.32) ^b	-0.10 (-0.24 to 0.03)	0.1
MH2	0.85 (0.30)	0.70 (0.34)	0.86 (0.21)	-0.16 (-0.29 to -0.03)	0.02	0.63 (0.48)	0.86 (0.22)	-0.23 (-0.45 to -0.02)	0.04

^aPeak values are reported as mean values with standard deviation. Differences between the outcomes before and after PAO were tested with paired t-test and reported as mean differences (95% CI). Differences between patients and healthy controls were tested with unpaired t-test.

^bSignificantly different compared to healthy controls.

PAO: periacetabular osteotomy; MA1: peak dorsiflexion moment in the first half of the stance phase; MA2: peak plantar flexion moment in the second half of the stance phase; MK1 and MK2: peak flexion and extension moments in the first half of the stance phase; MK3 and MK4: peak flexion and extension moments in the second half of the stance phase; MH1: peak hip extension moment in the first half of the stance phase; MH2: peak hip flexion moment in the second half of the stance phase.