Hip dysplasia (or acetabular dysplasia) is a condition where the hip joint doesn’t function correctly. In babies, it may be called “developmental dysplasia of the hip” (DDH) or “congenital hip dislocation” (CHD).
The hip joint is shaped like a ball and socket. The “ball” is the femoral head (the top of the thigh bone/femur) and the “socket” is the pelvis (or acetabulum), which is shaped like a cup. In hip dysplasia, the socket is too shallow, meaning the femoral head is not held in place correctly. This can cause the joint to function incorrectly, leading to injuries and, in more severe cases, the ball coming out of the socket (known as dislocation). The condition puts extra pressure on the hip, so it will usually “wear out” more quickly. This can cause arthritis or the need for joint replacement. It ranges from very mild to severe and can affect one or both sides of the hip. Hip dysplasia usually occurs in newborns or young babies, but symptoms and diagnosis may not happen until adolescence or adulthood.
Hip dysplasia in babies can occur either in the womb or during birth. When babies are very young, methods to wrap them (known as swaddling) or restrictive car seats may be a factor. It is not clear exactly what causes hip dysplasia in adults, but it is thought it may be due to under-development of the hip socket during infancy. You are more likely to get hip dysplasia if you have a family history of the condition.
Many people with hip dysplasia do not develop any symptoms until later in life, especially in mild cases. The first signs are often “clicky hips” in babies, but in older people it usually presents itself with pain or limping. The pain can be felt in the groin or around the hip. It can feel like stabbing pain or a dull ache and may be worse after sitting for long periods. Other symptoms include leg length differences, lower back pain and movement or mobility issues, especially after long walks or exercise. Dislocation of the hip (when the femur comes out of the socket) can occur due to overstretched ligaments or just the feeling of the hip “giving way”.
Because parts of the joint have additional pressure on them, conditions like hip labral tear can develop. This is where the soft cartilage (labrum) that lines the hip socket becomes damaged. The cartilage wearing away means people with hip dysplasia are significantly more likely to get early osteoarthritis in that joint - sometimes even in patients in their teens. Osteoarthritis is a progressive disease that gets worse with time and can cause pain and stiffness. Arthritic pain can become constant or even debilitating and, in more advanced cases, the bone can become so damaged it can impair the possibility of surgery.
Early diagnosis and treatment are important in preventing worsening symptoms later in life. In babies, a physical examination, including a hip joint exam, will be used and sometimes an ultrasound. Adults too will require a physical exam and possibly an x-ray. A CT or MRI scan may also be used. In adults, it could take the review of several specialists before a diagnosis is made.
In babies, some mild cases of hip dysplasia may resolve on their own. If not, a special corrective brace or harness may be worn for several months. In adults, because the problem is with an incorrectly formed joint, non-surgical methods will not solve the problem or provide any long-lasting solution. Non-surgical methods generally aim to prevent or slow down arthritis development and should therefore be started as early as possible. Some methods may be more suitable for patients with very mild hip dysplasia or for those whose hips are too arthritic for surgery.
Adults may be recommended to maintain or lose weight to prevent additional load on the joint. Low-impact exercise, such as swimming or stretching, and movement techniques, such as Tai Chi, may be recommended with specialised physiotherapy programmes. Oral supplements called glucosamine or chondroitin sulphate may be suggested for joint health and to relieve pain, but there are no trials that prove their effectiveness. Alterations in diet to reduce inflammation may be helpful.
Unfortunately, surgery is often required for adults with hip dysplasia. It can be used to preserve hip function or existing cartilage, or it can be used to alter the placement of the bones in the joint or replace them entirely. Below are a list of the possible surgical options:
- Hip Resurfacing: Hip resurfacing aims to prevent worsening cartilage loss or joint damage by replacing the surface lining in the hip with a metal covering. While this option removes less bone than other surgeries, it is not being used as often due to the damage that the metal can cause to the surrounding soft tissue.
- Hip Osteotomy: An osteotomy is an operation for people with arthritis who need the bones moved to a better position in order to “unload” the uneven weight. This can relieve pain as well as help to preserve joint function. Periacetabular osteotomy (or hip osteotomy) is an operation that helps move the hip socket into a position that better covers the femoral head. Cuts are made in the bones and they are moved to a new position where they are secured with screws. These operations tend to have the best results in patients up to 40 years of age and those whose cartilage is in relatively good condition. Older patients or those with significant cartilage damage are likely to be recommended a hip replacement. Learn More
- Total Hip Replacement: A total hip replacement is an operation that uses an artificial implant called a “prosthesis” to replace the damaged hip joint, often due to osteoarthritis. Prosthetic implants may be made from metal, ceramic or even tough plastic. The surgeon will make an incision (or cut) into the hip, remove the damaged hip joint and replace it with the prosthesis. A test called the Harris Hip Score may be used after surgery to check whether the surgery has been effective. For younger patients who are still growing, the joint may need to be replaced at a later date. This is the same with older patients if the implant “wears out”. Learn More