Hip Dysplasia

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The hip is a ball-and-socket joint. Hip dysplasia, often referred to as DDH (developmental dysplasia of the hip), is a relatively common abnormality of the hip joint where the acetabulum (socket) does not adequately cover the femoral head (ball). The shallowness of the acetabulum causes the femoral head to exert excessive pressure on the rim of the acetabulum. If left untreated, this excess rim pressure can lead to hip pain, cartilage damage and eventual osteoarthritis.

Hip dysplasia originates at birth or develops during childhood. Specific risk factors for hip dysplasia include a family history of hip dysplasia, breech position during pregnancy, female gender (females tend to have looser ligaments than males), first-born child, and high birth weight. The severity of hip dysplasia varies widely. In the mildest types of dysplasia, the hip is very close to normal on x-ray, and may not cause any symptoms until the patient is 30 years of age or older. In the most severe form of dysplasia, termed “developmental dislocation”, the femoral head of the infant or child actually lies outside of the acetabulum, resting under the muscles of the buttock and thigh.

At least 80% of osteoarthritis in the hip occurs because of a developmental abnormality such as hip dysplasia. Hip dysplasia is the most common developmental hip deformity causing symptoms in adults, and is the most common developmental hip deformity causing osteoarthritis. If hip dysplasia is detected early, surgery can be undertaken to improve hip function, reduce cartilage damage and delay or prevent the onset of osteoarthritis.

Not sure if your hip pain could be dysplasia? Dr. Boyle explains the signs to look for, how it's diagnosed, and when surgery becomes the right option.

Treatment Options For Hip Dysplasia

Non-Surgical Treatment 

Non-surgical treatment for hip dysplasia include physiotherapy (to strengthen muscles), activity restriction, and possibly weight loss. Although useful as a part of surgical interventions, non-operative measures to treat the symptoms of dysplasia do not treat the underlying mechanical problems.

Surgical Treatment

The surgical treatment of hip dysplasia is always more successful before excessive joint damage has occurred. Once cartilage is lost, it cannot be replaced. The goal of surgery is to slow or stop the progression of cartilage loss. Surgical treatment options include:

  • Periacetabular osteotomy (PAO). This is the primary surgical treatment for hip dysplasia. Only realignment surgery such as PAO can correct the underlying mechanical problem and abnormal orientation of the acetabulum. Learn more.

  • Hip Arthroscopy. This technique involves two to three small incisions which allow a camera and tiny instruments to be inserted into the hip joint. Arthroscopy alone cannot correct the major problem of acetabular dysplasia, however it can be useful in repairing labral tears or treating impingement.

  • Hip Arthrotomy. This is a procedure in which the capsule surrounding the hip joint is opened. Some minor problems of the labrum and femoral head can be treated with this procedure. This is sometimes performed at the same time as PAO.

  • Osteoplasty. This involves using special surgical instruments to shave down bone on the femoral head or acetabulum that may be causing impingement.

  • Total hip replacement (THR). Replacement of an arthritic joint with an artificial joint. Unfortunately, if THR is performed in young, active patients, the artificial joint is likely to wear out with time and require additional surgery.

  • Hip dysplasia, also called developmental dysplasia of the hip (DDH), occurs when the hip socket (acetabulum) is too shallow to fully cover and support the ball of the hip joint (femoral head). This can lead to instability, abnormal wear, and pain, and if untreated, early osteoarthritis.

  • Most adult hip dysplasia is a previously undiagnosed form present since birth or childhood that becomes symptomatic later in life, often in the teens, twenties, or thirties, as the joint accumulates wear. Some cases relate to a family history of hip problems or were missed during childhood screening.

  • Common symptoms include groin or hip pain, particularly with activity, a sense of the hip catching, clicking, or feeling unstable, and pain that gradually worsens over months or years. Many patients are active young adults who develop symptoms during or after sport.

  • Diagnosis typically involves a clinical examination followed by imaging: an x-ray to assess the shape and coverage of the hip socket, and often an MRI to check the cartilage and labrum for damage. Specific measurements on x-ray, such as the lateral centre-edge angle, help quantify the degree of dysplasia.

  • In mild cases, or where symptoms are manageable, physiotherapy, activity modification, and pain management can help. However, hip dysplasia doesn't correct itself, and for patients with significant dysplasia or ongoing symptoms, surgery is usually the only option that addresses the underlying structural problem.

  • PAO is generally recommended when dysplasia is causing pain or instability and the joint cartilage is still in good condition. It is most successful before significant arthritis develops, which is why earlier diagnosis and referral lead to better long-term outcomes.