It is important to accurately diagnose the status of idiopathic osteonecrosis of the femoral head and to consider another possible pathogenesis when a patient with idiopathic osteonecrosis of the femoral head has hip pain even without femoral-head collapse.

Ignored or misdiagnosed concomitant femoroacetabular impingement in a patient with idiopathic osteonecrosis of the femoral head might leads to poor outcomes of surgical treatments such as bipolar hemiarthroplasty or osteotomies.

In a patient with idiopathic osteonecrosis of the femoral head, it should be paid attention if concomitant femoroacetabular impingement exists or not.