Table 2 Joint kinematics and kinetics during level gait at self-selected walking speed in a group of children with achondroplasia and in a group of age-matched controls

Pelvis

 Peak anterior pelvic tilt

20.0 (7.1)

11.0 (4.4)

0.000

 Pelvic obliquity range

7.4 (2.1)

8.0 (3.3)

0.486

 Pelvic rotation range

19.6 (6.4)

12.2 (4.8)

0.000

 Peak hip flexion (+)

33.2 (9.8)

34.9 (5.5)

0.508

 Peak hip extension (−)

−9.8 (7.8)

−12.9 (7.2)

0.230

 Peak hip adduction (+)

−1.4 (4.9)

3.3 (4.1)

0.004

 Peak hip external rotation (−)

− 25.8 (9.9)

−7.9 (7.5)

0.000

 Knee at initial contact

0.7 (10.7)

7.3 (3.7)

0.018

 Knee at loading response (10% of gait cycle)

11.7 (13.4)

19.4 (4.7)

0.025

 Knee at terminal stance (40% of gait cycle)

10.3 (8.0)

4.3 (4.9)

0.011

 Peak knee varus in stance

12.5 (7.1)

4.1 (3.8)

0.000

 Peak knee flexion in swing

62.4 (7.3)

57.8 (6.0)

0.049

 Peak ankle dorsiflexion (+)

18.9 (4.7)

12.6 (6.8)

0.004

 Peak ankle plantarflexion (−)

−11.4 (6.9)

−15.9 (12.1)

0.193

 Peak external (−) foot progression

− 12.3 (9.9)

−11.5 (5.9)

0.762

Kinetics expressed by internal moments (Nm/bodyweight)

Achondroplasia group (n = 12)

Control group (n = 18)

p-value

 Peak hip extension moment

0.44 (0.16)

0.84 (0.26)

0.000

 Peak hip flexion moment

−0.87 (0.25)

−0.69 (0.20)

0.033

 Peak hip abduction moment

0.46 (0.14)

0.60 (0.15)

0.018

 Peak knee flexion moment

−0.20 (0.07)

−0.36 (0.12)

0.000

 Peak knee extension moment

0.44 (0.21)

0.66 (0.25)

0.016

 Peak knee valgus moment

0.45 (0.21)

0.39 (0.10)

0.390

 Peak ankle plantarflexion moment

0.90 (0.19)

1.31 (0.20)

0.000