Static and Dynamic Mechanical Causes of Hip Pain

Mechanical hip pain typically has been associated either with dynamic factors resulting in abnormal stress and contact between the femoral head and acetabular rim when the hip is in motion or with static overload stresses related to insufficient congruency between the head and acetabular socket in the axially loaded (standing) position. Compensatory motion may adversely affect the dynamic muscle forces in the pelvic region, leading to further strain and pain. Hip pain related to static overload stresses may also be localized to the anteromedial groin, but compensatory dysfunction of the periarticular musculature may lead to muscular fatigue and associated pain throughout the hip. As our understanding of hip joint mechanics has advanced, it has become increasingly apparent that hip pain in the absence of osteoarthritis may be due to a complex combination of mechanical stresses, both dynamic and static. With an emphasis on findings in the recent literature, this review will describe the dynamic and static factors associated with mechanical hip pain, the combinations of dynamic and static stresses that are commonly identified in hip pain, and common patterns of compensatory injury in patients with femoroacetabular impingement.