Cam impingement causes osteoarthritis of the hip: a nationwide prospective cohort study (CHECK)

To determine the association between cam impingement, which is hip incongruity by a non-spherical femoral head and development of osteoarthritis.A nationwide prospective cohort study of 1002 early symptomatic osteoarthritis patients (CHECK), of which standardised anteroposterior pelvic radiographs were obtained at baseline and at 2 and 5 years follow-up. Asphericity of the femoral head was measured by the α angle. Clinically, decreased internal...