A study of radiographic variations of the hip joint

Anteroposterior radiographs of the pelvis were studied in 920 patients free of hip joint diseases. The average joint space was between 3 and 4 mm in width. Narrowing of the superior joint space was seen in 13 percent of the hips and may represent the earliest finding in osteoarthritis. It was noted as early as the second and third decade in some patients. Other changes noted were narrowing of the lateral joint space, uniform narrowing of the space, an irregular joint space and tilting of the femoral head on the neck.