Pedersen Eva N G, Simonsen Erik B, Alkjaer Tine, Søballe Kjeld
The Medical Research Unit, Ringkøbing, Denmark.
Acta Orthop Scand. 2004 Feb;75(1):2-9. doi: 10.1080/00016470410001708010.
Knowledge of the gait dynamics in patients with hip dysplasia may help to understand the consequences of the mechanical changes in the hip.
We evaluated the walking pattern of 14 women with hip dysplasia (median age 39 (24-50) years) before periacetabular osteotomy and compared it with a control group of 12 healthy women (median age 35 (24-56) years). Data were collected using five video cameras and two force plates. We used an inverse dynamics approach to calculate sagittal joint angles, moments and power in the stance phase.
The patient group showed increased dorsiflexion of the ankle and knee flexion in the second half of the stance phase. The hip flexor joint moment in the patient group was both delayed and reduced in the second half of the stance phase. Moreover, the angular impulse of the hip flexors was significantly reduced in the patient group.
The pathological deformities of hip dysplasia may explain both the kinematic and kinetic gait deviations between the patient group and the control group in the second half of the stance phase. We suggest that insufficient cover of the femoral head leads to a reduced hip flexor moment and an increased flexion in the ankle, knee and hip joints.
