X-rays are the key to making a diagnosis of hip impingement. With hip impingement, the head of the femur (thigh bone) bumps up against the lip or rim of the socket. A thin layer of cartilage called the labrum gets pinched in the process causing pain. This problem is often treated with surgery, so the imaging studies from all angles are essential.
There are three main ways X-rays can be taken. Each radiographic view offers a slightly different picture of the hip angle and shape. This information is important in diagnosing hip problems such as impingement.
The first is the anterior-posterior (AP) view. This is the view looking through the patient from the front to back. Second is the lateral view from the side. And third is the frog-leg lateral view.
In the frog-leg view, the patient lies on his or her back. The leg is flexed and abducted away from the body. The hip is externally rotated. The knee is bent so that the foot rests against the other leg. The frog-leg view has been shown to be a reliable way to diagnose hip impingement.