Introduction to Total Hip Replacement

Every time we move from place to place we move our hip. Every time we go to the bank, or even walk to the kitchen, we use our hip joint. That is why a painful joint or a joint that doesn't function properly can be very frustrating and cause a lot of problems in our day to day life. Hip pain can affect people of all ages and it may keep you from activities that you enjoy. A painful hip may even prevent you from keeping up with your daily activities. Causes of hip pain may be:

These X-rays depict the difference between a normal hip (left) and an arthritic hip.

• An old fracture that didn't heal appropriately
• A systemic disease
• Wear and tear from years of constant use, known as osteoarthritis.

Advantages and Benefits of Hip Replacement Surgery

• A total hip replacement can greatly reduce hip pain. After the pain from surgery goes away, many patients are pain-free
• The strength of your leg will improve.Without pain coming from your hip joint, you'll be able to move more freely and exercise. This builds up the muscles around the hip joint and within your leg
• Without pain in your hip joint and with increased range of motion, you'll be able to perform activities of daily living and other activities that were limited by pain before surgery
• Since most total hip replacements last for several years, you will be able to freely move your hip joint for years to come.

Anatomy of the Hip Joint

The hip joint is the body's largest weight bearing joint. It is a ball and socket type joint- the ball consists of the femoral head and the socket is also known as the acetabulum. This type of joint offers some stability and a large range of motion.

Parts of the Hip

• Bones: The femoral head is a ball at the top end of the femur, or thigh bone. This articulates, or forms a joint, with the acetabulum which is the socket of the hip bone
• Cartilage: This is a soft, smooth tissue that covers the ball of the femur and lines the socket of the hip bone. This cartilage functions as a shock absorber and is a smooth lubricated surface that reduces friction when the joint moves
• Muscles: Muscles, such as the gluteal muscles (muscles of the buttocks), provide power to the hip and leg and allow us to walk, run and stand. These muscles also provide support and stability for the hip joint
• Tendons: These attach the muscles to the bones
• Ligaments: These soft tissue structures around the hip joint provide stability to the joint.

X-Rays

X-rays, or radiographs, are taken to allow the surgeon to see if there is a problem with the bony structure of the hip joint. An x-ray may show abnormalities in the size, shape, and position of the joint. Important signs of arthritic changes are joint space narrowing, osteophyte (bone spur) formation, which is a growth of bone in areas where there is arthritis. It may also show cyst formation or sclerosis. These signs are commonly seen when the cartilage wears away and the bones grind against each other (eburnate). X-rays are also used to help the surgeon plan the hip replacement surgery.

Total Hip Replacement restores movement lost by joint damage

Indications for a Total Hip Replacement

When the bony parts of the hip are damaged, movement becomes very painful. The joint may not move easily and the muscles surrounding it stiffen. As time goes on, the cartilage on the joint surface starts to wear away. When parts of the cartilage completely wear away, the bones that make up the joint rub together. This can cause severe pain and stiffness and lead to further damage. This can cause the surrounding muscles to stiffen and occasionally spasm.

Some Causes of Hip Joint Damage:

• Osteoarthritis: As we get older, normal wear and tear can cause damage to the cartilage. As the cartilage continues to wear away, the bones rub together and damage the joint
• Inflammatory Arthritis: Diseases such as rheumatoid arthritis or gout can cause swelling and inflammation in the joint lining. This inflammation can lead to destruction of the joint cartilage
• Fractures/Injuries: A traumatic fall on the hip can fracture the femoral neck (the area of the thigh bone just below the femoral head. If this fracture is not treated correctly or does not heal properly, the bone will lose its blood supply, thus leading to osteonecrosis and subsequent arthritis of the hip
• Avascular Necrosis: If there's a trauma to the thigh bone that disrupts the blood supply to the bone, or if the patient has associated risk factors such as using corticosteroids or drinking alcohol, bone necrosis may occur. This is a process in which the bone cells actually die and this leads to joint destruction. This is also known as osteonecrosis, ischemic necrosis, and aseptic necrosis.

There are currently several methods used for attaching the prosthesis to the bone and providing stable fixation:

• Bone Cement (polymethyl methacrylate): This material acts like glue or a grouting material
• Press Fit: This depends on a very tight fit of the device into the bone
• Biological Ingrowth: No cement is used in this procedure. The metal prosthesis is fabricated with a porous coating, which allows the bone to actually grow into the prosthesis.

The type of prosthesis used for your surgery is usually determined by the surgeon and is based on a number of factors such as your height, weight, age, and bony structure.  To find out more about the technologies available and what these prosthesis look like, click on Hip Prosthesis.

The Surgical Procedure

Once you are taken into the operating room, you will be given anesthesia. If it is general anesthesia, you will sleep through the surgery. If it is spinal anesthesia, however, you will not be able to feel anything from the waist down. You will also receive some type of sedation with the spinal anesthesia.

X-ray: Prosthetic Hip Joint

Then an incision about 10 inches long is made down the side of your hip. Some of the soft tissue is cut to expose the hip joint. The damaged femoral head is then removed and the surface of the old socket is reamed (smoothed) The prosthetic socket is then placed in the pelvis, or hip bone. The prosthetic stem is placed into the femur (thigh bone) and the new ball and socket joint are articulated, or joined. Once the prosthesis is in place, the muscles and soft tissue are re-approximated with sutures and the skin is closed with staples.

Complications

As with any type of surgical procedure, there are certain risks or complications associated with a total hip replacement. We are continually striving to provide the optimum environment for your surgery and recovery, minimizing any potential complications. Possible problems include, but are not limited to, reactions to anesthesia, blood clots, dislocation, injury to a nerve or blood vessel, fracture, infection, and swelling. It is our primary goal to help you through your total joint replacement procedure with minimal complications and maximum recovery. Therefore, we will instruct you in measures that will aid you in having a rapid recovery.

Prosthetic Hip Joint

Special Situations - Bilateral Hip Replacement and Revision Hip Replacement

There may be a need, in some cases, for both hips to be replaced at the same time. Patients in this category have significant disease in both hips. Others will require revision surgery due to a previously failed hip implant.

Because of the more extensive nature of these surgeries, special devices may be needed to monitor your status more closely during and after surgery. If you are having bilateral hip surgery, your surgeon will typically replace the more symptomatic joint first. If the surgeon and the anesthesiologist are satisfied with your stability, the second joint will be replaced. If only one joint is able to be replaced, the other joint can usually be replaced after about one month.

After bilateral hip replacement, your progress may or may not be slower, depending on many factors such as age or your physical condition prior to surgery. Patients requiring revision surgery will have a more restricted physical therapy program, both at the hospital and at home.

Your program will be tailored to give you optimal function within the parameters your surgeon has set so that you will get optimal results from your surgery.

Center for Joint Preservation and Reconstruction
Sinai Hospital of Baltimore
Department of Orthopedics
2401 West Belvedere Avenue
Baltimore, Maryland 21215 USA