Total Hip Replacement

Anatomy & Arthritis

The hip joint is where the femur (thigh bone) and pelvis meet and consists of a ball and socket joint. The socket, called the acetabulum, is a part of the pelvis and accepts the ball, called the head of the femur (femoral head).

The acetabulum and femoral head are both covered by a thick layer of articular cartilage that allows the head pivot inside the acetabulum in a nearly frictionless and pain free manner. The rim of the acetabulum is lined with a different and thicker type of cartilage called the labrum, which serves to make the socket deeper and reduces the stresses across the articular cartilage.

Hip Arthritis

As in any other joint, the articular cartilage that allows for smooth and pain-free motion of the hip joint can erode, leaving the exposed bone of the femoral head and the exposed bone of the acetabulum to rub against one another. This can result in pain and stiffness. Many patients with arthritis of the hip complain of pain in the front of the hip (groin area), back of the hip (buttock), or on the side. An additional complaint is stiffness of the hip joint making simple activities such as donning shoes and socks quite difficult.

Arthritis is the most common cause of the breakdown of hip cartilage:

Osteoarthritis: also referred to as “wear and tear” arthritis; osteoarthritis affects the cartilage that cushions the bones of the hip. As this cartilage wears away, the ends of the bones rub together causing a grinding feeling, hip pain and resulting stiffness.

Rheumatoid Arthritis: a systemic disease, which affects multiple joints in the body. The synovial membrane, which lines the entire joint cavity becomes irritated and produces too much fluid. The resulting healing response damages the cartilage, leading to pain and stiffness. Rheumatoid arthritis starts in much younger patients.

Treatment

Non-Surgical Treatment

In most cases, non-surgical treatments are exhausted before operative measures are considered. These include:

• Physical therapy
• Weight loss
• Modifying your activities
• Using assistive devices, such as a cane
• Anti-inflammatory medicines

Physical therapy and exercise can help keep your joints flexible, strengthens the muscles around the joints, reduces pain and keeps your bone and cartilage tissue strong and healthy. If you start an exercise regimen, take a balanced approach and include aerobic activities such as walking, swimming and cycling in addition to stretching/flexibility exercises and strengthening exercises. You want to avoid exercises that place excessive stress on the joints like high-impact workouts or competitive sports activities.

Losing weight can have a surprising effect on reducing arthritic pain. With each step, you exert 4-7 times your body weight on your hip joints. So when you lose even a small amount of weight, your symptoms improve dramatically and you may be able to perform more activities and potentially put off surgery for six months or longer.

Activity modifications include reducing high-impact and repetitive activities that place increased stresses on the hip joint. Guided yoga or pilates can also help reduce pain and improve mobility.

The use of a cane, usually in the hand opposite the affected hip, can reduce the stress across the hip joint. Anti-inflammatory medicines, such as ibuprofen and naproxen, can reduce the inflammation around the knee joint that is caused by the arthritis and provide significant pain relief.

If all non-operative treatments have been attempted and fail to reduce pain, then surgery to replace the hip joint is the last option.

Surgical Treatment

A total hip replacement (THR) is performed in patients with severe wear and loss of cartilage in the hip joint due to injury, trauma or for types of arthritis or other congenital or age-related changes to the hip joint.

In a THR, the damaged femoral and the damaged hip socket (acetabulum) are removed and replaced with metal, plastic, or ceramic components depending upon your unique needs and condition.

The pioneering work of this procedure began in the early 1960’s with significant advancements made by our physicians and scientists here in our Orthopaedic Research Laboratories at Mass General Hospital.

Revision THR

A total hip replacement permits patients to participate in most activities of daily living pain-free for 10-20 years after surgery and sometimes longer. Over time, the implants wear out and loosen, resulting in pain, stiffness or instability. Your doctor will compare a series of your x-rays to observe changes in implant position or condition of bone surrounding the implant and decide if a revision surgery is necessary.

Hip Resurfacing

Unlike traditional total hip replacement, in hip resurfacing, the femoral head is not removed but instead is trimmed, shaped and capped with a smooth metal covering. The damaged bone and cartilage within the socket is removed and replaced with a metal shell, just as in a traditional THR.

Hip resurfacing is beneficial for only a very small number of patients and is performed infrequently at MGH. An evaluation by your orthopaedic surgeon will determine if you are a candidate for hip resurfacing. In addition, all resurfacing implants are metal-on-metal devices, and these devices have unique risks and considerations to take into account as we learn more about wear and loosening in these devices.