Developmental hip dysplasia (DDH) is probably present at birth or occurs during development in the early years. A change in the normal anatomy results in a shallow hip socket. The angle or tilt of the femur (thigh bone) and rotation of the femoral shaft (long part of the bone) are also different from normal. The patient is at increased risk of partial dislocation called subluxation or even full dislocation.
According to at least one study, this condition occurs in about five to 13 percent of the adult population. The person may not even know it’s there until pain sends him or her to the doctor for an X-ray.
There is some evidence that dysplastic hips have an uneven load across the joint. The cartilage on the surface of the joint can get damaged directly. Abnormal stresses on the soft tissues supporting the joint can lead to wear and tear of ligaments and cartilage.
Damage to the cartilage around the rim of the socket changes the pressure inside the joint. Synovial fluid that lubricates the joint may leak out adding to the wearing away of the cartilage.
No one is quite sure if these changes always occur or how long it takes before they result in arthritis. One study from Denmark reported no adverse changes even after 10 years of untreated DDH. It may be best to treat the hip conservatively but keep contact with your doctor. Any change in symptoms should be re-evaluated sooner than later to prevent excessive damage.