Femoroacetabular impingement alters hip and pelvic biomechanics during gait Walking biomechanics of FAI.

Femoroacetabular impingement (FAI) has been reported to cause hip pain in a variety of daily activities including walking. However, the biomechanics of level gait has not been compared between FAI patients and a control group. This study quantified the affect of cam FAI on the three-dimensional (3-D) kinematics of the hip and pelvis, as well as the 3-D kinetics generated at the hip during walking. A unilateral cam impingement group (n=17) was compared to a matched control group (n=14) using between-group one-way ANOVAs. The FAI group had significantly lower peak hip abduction (p=0.009), frontal range of motion (ROM) (p=0.003), as well as attenuated pelvic frontal ROM (pelvic roll) (p=0.004) compared to the controls during level gait. There was also a trend of the impinged group having a lower sagittal ROM (p=0.047) than the controls. However, there were no kinetic differences between the two groups. Attenuated hip abduction, frontal ROM and sagittal ROM during gait in FAI individuals may be caused by soft tissue restriction, and decreased frontal pelvic ROM could result from limited mobility at the sacro-lumbar joint.