The effect of unilateral cam femoroacetabular impingement on the three-dimensional kinematics of the pelvis and hip and the kinetics of the hip.

摘要

Cam femoroacetabular impingement (FAI) is caused by decreased concavity of the femoral head-neck junction which results in a jamming of the proximal femur into the acetabulum within normal range of motion (ROM). This condition is known to decrease hip ROM, and has been reported to cause hip pain in a variety of daily activities including sitting and walking, and activities requiring large hip mobility. It is important to determine the effect of cam FAI on self-generated dynamic ROM and common daily activities in order to ascertain its influence on hip functionality. This study measured the effect of cam FAI on total dynamic hip ROM, and the biomechanics of the hip and pelvis during walking, sitting, standing and maximal depth squats. A cam impingement group (n = 17) was compared to a matched control group (n = 14) using between-group one-way ANOVAs. The level of variability for sitting and standing strategies was also compared between the two groups using F-tests. For maximal dynamic hip mobility, the FAI group had a decreased flexed internal rotation, external rotation and total transverse ROM, as well as decreased hip abduction and total sagittal ROM compared to the matched control group. For walking, the FAI had significantly lower peak hip abduction, frontal ROM, and sagittal ROM than the controls, as well as attenuated pelvic frontal ROM. Reduced hip mobility during gait may be caused by soft tissue restriction, and FAI participants may have decreased pelvic mobility in the frontal plane. For the sit-to-stand and stand-to-sit manoeuvres there were no significant differences in peak kinematic or kinetic values of the hip and pelvis between the two groups. However, the cam FAI group had significantly higher variability in peak angles in the frontal plane, and peak hip extension moments of force during both sitting and standing. This likely resulted from the FAI group having varying sit and stand compensatory strategies. For the 2 maximal depth squat the FAI group had decreased sagittal pelvic range of motion and could not squat as deep as the control group. Limited pelvic ROM in FAI patients reduces their capacity to perform motions requiring large amplitudes at the hip joint such as maximum squat. Restricted pelvic sagittal ROM could represent a key factor in the pathomechanics of FAI.