Understanding Hip Dysplasia

Adults - Diagnosis

Adult Diagnosis

Hip Dysplasia is usually diagnosed by an experienced physician using the combination of symptoms, hip examination, and x-ray findings. One study showed that adult patients with hip dysplasia may see more than three healthcare providers and have symptoms for five years before a correct diagnosis is made. This is improving because of increased awareness by physicians and through IHDI educational efforts. However, a second opinion may be worthwhile if you have continuing hip pain.


Hip pain or limp are usually the first signs of hip dysplasia in an adolescent or young adult. Occasionally a limp may occur without pain during walking because limping is one of the body’s natural methods of decreasing pain. However, these symptoms can also be caused by many other hip disorders.

Two or more of the following symptoms increases the likelihood that your pain is caused by hip dysplasia.

  • Pain from hip dysplasia is deep in the front of the groin in four out of five patients with hip dysplasia– this may be caused by labral tears, cartilage damage in the joint, or painful hip flexor muscles (see anatomy and terminology).
  • Muscle ache on the side of the hip or in front of the hip can also be caused by stabilizing hip flexor and abductor muscles that are overworked when the socket is shallow (see anatomy and terminology).
  • Hip pain increases when walking, standing or running in almost all patients with hip dysplasia.
  • Pain at night when resting occurs in half of all patients with hip dysplasia.
  • A sensation of catching, snapping, popping, or locking that is usually painful. Four out of five patients with hip dysplasia report this.

Other characteristics of hip dysplasia:

  • Pain in the thigh or buttocks is uncommon unless there is also pain in the groin or side of the hip.
  • At first the pain may be mild or intermittent, but pain from hip dysplasia increases with time.
  • The character of the pain may be sharp, or it may be a dull ache, or a combination of both from time to time.


Limping is common during the early stages of hip dysplasia symptoms. The most common cause of a limp is pain. However, a painless limp can occur because of weak muscles, joint stiffness, bone deformity, or because the limp relieves the pain.

A limp or pain does not necessarily mean that someone has hip dysplasia because limp and pain can be caused by many hip disorders. To learn more about adult related hip disorders click here.


The doctor may have you stand to look for pelvic tilt, leg length discrepancy, or muscle wasting. This is generally followed by moving the hip through a full range of movement. Motion is not normally limited by hip dysplasia although pain or muscle tightness is often noticed when the leg is spread away from the body – hip abduction.

During walking most patients will limp because of dropping of the affected side of the pelvis. This dropping may also occur when standing on the affected hip. This is called the Trendelenburg test.

A test called the impingement test causes a pinching sensation in almost all patients with hip dysplasia. This may occur when a torn labrum or the tender edge of the socket is pinched. The test for impingement is usually done by flexing the hip and then twisting the hip inwards to rub the femoral neck against the edge of the hip socket.

X-Ray Diagnosis

An x-ray can identify hip dysplasia by the shallow socket (acetabulum), and by displacement of the ball (femoral head) from the socket.

Hip Joint pain radiates from the front of the thigh and or groin area.

X-rays can determine the severity of dysplasia, which helps to establish the need for surgery. There are several ways that the amount of dysplasia can be measured on x-rays.

A common measurement for the depth of the socket is the center-edge angle (C-E angle). The normal C-E angle is 25° or more.

X-rays also show whether hips are also displaced in an upward direction; this information is valuable because hips that are displaced upward usually wear out faster than hips that are not displaced upward.

An MRI may also be helpful to diagnose hip dysplasia and give the physician information on any damage to the cartilage and labrum.

Classifications of Severity

Treatment decisions for adults generally depend on the age of the person, the extent of deterioration of the joint surface and the amount of displacement of the hip from the socket.

Arthritis Classification of Tönnis

Amount of arthritis is classified according to the amount of wear and deterioration of the joint surfaces. Hip preservation with PAO surgery may be possible for younger adults with lesser amounts of arthritis.

Displacement Classifications of Crowe and Hartofilakidis

Both of these classifications are helpful to plan total hip replacement. Different surgical procedures are generally used depending upon the severity of displacement. Also, more severe displacement can lead to longer hospitalizations and greater risk of problems after total hip replacement.