Bilateral sunrise views of the patellofemoral joint

Bilateral sunrise x-rays of the patellofemoral joint are obtained to confirm subluxation, early cartilagenous injury, or patellofemoral arthritis. The position of the patella should be centered in the femoral groove. The thicknesses of the medial and lateral cartilage should be equal. With advancing wear and tear, the lateral cartilage thins, the subchondral bone thickens, and, in rare cases, osteochondritis dessicans occurs.