Hip Replacement - Computer Assisted Surgery
Patient Guide
Introduction
Anatomy
Arthritis
Alternatives
Hip replacement
CAS hip
Surgery day
Post-op care
Rehabilitation
After surgery
Information for Patients Facing a Hip Replacement
Introduction
By reading this article, you will be able to gather information about:
- Hip anatomy> bones, cartilage, ligaments and muscles
- Hip arthritis> causes, symptoms and treatment
- Non-surgical alternatives>conservative measures to relieve your pain
- Total hip replacement> implant components and procedure
- Computer-assisted hip replacement> the new solution, how it works, patient benefits and equipment
- Surgery day> pre-operative procedures, preparation for the hospital, day of surgery and recovery
- Post-operative care> possible complications and precautions
Rehabilitation> early rehabilitation, precautions, at home and long-term goals - Life after hip surgery> activities to avoid and how long your implant will last.
Anatomy
The hip joint functions as one of the most important joints in the human body. Designed for both mobility and stability, the hip allows the entire lower extremity to move in three planes of motion, while providing an important shock absorption function to the torso and upper body. The hip is a ball and socket joint, uniting the femur (thigh bone) with the pelvis. As a result of this configuration, the leg moves forwards and backwards, side to side, and rotates to the right and left.
Bones
The pelvis features two cup-shaped depressions called the acetabulum, one on either side of the body. The femur, or thigh bone, is the longest bone in the body and connects to the pelvis at the hip joint. The head of the femur, shaped like a ball, fits tightly into the acetabulum, forming the ball and socket joint of the hip.
Embedded within the acetabulum of the pelvis lies an important structure known as articular cartilage; this cartilage has two very important functions. First, the smooth, low friction surface of the cartilage allows the hip joint
to move freely in all planes of movement. Second, the articular cartilage cushions the hip during weight bearing activities, providing an important shock absorption function to the entire lower extremity.
Ligaments
The hip joint also features a complex system of ligaments that provide stability for the pelvis and lower extremity. The ligaments of the hip joint connect the femur to the pelvis and are essential to keeping the hip from moving outside of its normal planes of movement.
The muscles of the hip joint have dual responsibilities. They provide the dynamic functions necessary to raise and lower the lower extremity as well as the stabilizing functions required during standing, walking, or other weight-bearing exercises. This complex system of muscles works synergistically to provide the power for the hip to move in all directions, as well as to stabilize the entire lower extremity during weight.
Hip Arthritis
Osteoarthritis
Osteoarthritis, which is the most common form of arthritis in the United States; it is degenerative and although it most often occurs in patients over the age of 50, it can occur at any age, especially if the joint is in some way damaged.
It is usually confined to the large weight-bearing joints of the lower extremities, including the hips and knees, but may affect the spine and upper extremity joints, too. Patients with osteoarthritis often develop large bone spurts, or osteophytes, around the joint, further limiting motion.
Osteoarthritis of the hip is a condition commonly referred to as "wear and tear" arthritis. Although the degenerative process may accelerate in persons with a previous hip injury, many cases of osteoarthritis occur when the hip simply wears out. Some experts believe there may be a genetic predisposition in people who develop osteoarthritis of the hip. Abnormalities of the hip due to previous fractures or childhood disorders may also lead to a degenerative hip. Osteoarthritis of the hip is the most common cause for total hip replacement surgery.
The first and most common symptom of osteoarthritis is pain in the hip or groin area during weight bearing activities such as walking. People with hip pain usually compensate by limping, or reducing the force on the arthritic hip.
Treatment
Before considering total hip replacement surgery, your doctor and you may try various non-surgical therapies. An appropriate weight reduction program may be beneficial in decreasing force across the hip joint. However, weight reduction can be difficult for people with hip arthritis since the arthritis pain precludes them from increasing their activity and burning calories. An exercise program may be instituted to improve the strength and flexibility of the hip and the other lower extremity joints. Lifestyle and activity modification may be undertaken in an attempt to minimize the activities that are associated with hip pain. Finally, various medications such as non-steroidal anti-inflammatory drugs (NSAIDs) and/or nutritional supplements (Chondroitin/Glucosamine) to reduce pain and inflammation associated with the disease may be considered.
Assistive devices like a cane or a crutch can help to reduce the force transmitted through the hip joint during walking and thereby may help to decrease hip arthritis pain. If non-surgical treatment is unsuccessful, you and your surgeon may decide that a total hip replacement is the best available treatment option.
Rheumatoid arthritis
Unlike osteoarthritis which is a "wear and tear" phenomenon, rheumatoid arthritis is a chronic inflammatory disease that results in joint pain, stiffness and swelling. The disease process leads to severe, and at times rapid, deterioration of multiple joints, resulting in severe pain and loss of function.
Although the exact cause of rheumatoid arthritis is unknown, some experts believe that a virus or bacteria may trigger the disease in people having a genetic predisposition to rheumatoid arthritis. Many doctors think rheumatoid arthritis is an autoimmune disease in which the synovial tissue of the joint is attacked by one's own immune system. The onset of rheumatoid arthritis occurs most frequently in middle age and is more common among women.
The primary symptoms of rheumatoid arthritis are similar to osteoarthritis and include pain, swelling and the loss of motion. In addition, other symptoms may include loss of appetite, fever, energy loss, anemia, and rheumatoid nodules (lumps of tissue under the skin). People suffering with rheumatoid arthritis commonly have periods of exacerbation or "flare ups" where multiple joints may be painful and stiff.
Treatment of rheumatoid arthritis may involve medications such as NSAIDs, aspirin and analgesics. Corticosteroids, such as prednisone may be prescribed, and are effective in decreasing the inflammation associated with rheumatoid arthritis. Side effects can occur with the use of corticosteroids, and close monitoring by a physician is essential. Researchers have made progress in the treatment of rheumatoid arthritis and newer prescription drugs are now available. If non-surgical measures fail, you and your surgeon may decide that total hip replacement is the best treatment option to relieve your pain and help you return to an improved functional level.
Non-Surgical Alternatives
Before deciding on hip surgery, your physician may try several non-surgical, conservative measures to relieve the pain and inflammation in your hip.
The first alternative to hip replacement involves such lifestyle modification measures as weight loss, avoiding activities involving long periods of standing or walking, and the use of a cane to decrease the stress on the painful hip.
Exercise and physical therapy may be prescribed to improve the strength and flexibility of your hip and other lower extremity muscles. Your exercise program may include riding a stationary bike, light weight training and flexibility exercises. An aquatic therapy program is especially effective for the treatment of arthritis since it allows mild resistance while removing weight bearing stresses. For an appropriate exercise program, contact an experienced physical therapist.
Arthritis pain is primarily caused by inflammation in the hip joint. Reducing the inflammation of the tissue in the hip can provide temporary relief from pain and may delay hip replacement surgery.
In a small number of cases, the doctor may prescribe corticosteroids, such as prednisone or cortisone, if NSAIDs are not effective. However, due to the higher rate of side effects associated with corticosteriods, a physician must closely monitor their use.
Glucosamine/Chondroitin
Two dietary supplements, Glucosamine and Chondroitin (commonly available in a combined tablet), may decrease the symptoms of hip arthritis. Glucosamine and Chondroitin sulfate are both naturally occurring molecules, and issues associated with both remain under active research. However, it appears that may people taking these nutrition supplements on a regular basis note a decrease in their arthritis symptoms.
There exist a number of non-surgical alternatives to total hip replacement surgery. Such measures as lifestyle modification, exercise and physical therapy, and medication should be implemented before deciding on surgery.
If all of these measures have been exhausted and your orthopedist recommends surgical intervention, total hip replacement surgery can be very successful in decreasing pain and greatly improving function.
Total Hip Replacement
Your hips work hard during your daily routine, and arthritis of the hip or a hip injury can make it hard for you to perform normal tasks. If your injury or arthritis is severe, you may begin experience pain when you're sitting down or trying to sleep. Sometimes a total hip replacement is the only option for reducing pain and restoring a normal activity level. If you and your doctor decide a total hip replacement is right for you, the following information will give you an understanding about what to expect.
A total hip replacement involves cutting away the damaged bone of the hip joint and replacing it with a prosthesis. This "new joint" prevents the bones from rubbing together and provides a smooth hip joint.
Implant components
In the total hip replacement procedure, each prosthesis
is made up of two major parts. The femoral component is a metal shaft with a ball on the end and replaces the top of the femur. The acetabular component replaces the socket side of the joint and is made of a metal cup and plastic liner.
Before you are taken to the operating room you'll be given medication to help you relax, and the anesthesiologist will talk with you about the medications he'll be using. In the operating room, you will be placed under full anesthesia. Once you are "under" the surgeon will begin by making an incision in your leg to allow access to the hip joint. He'll then expose the joint and place a cutting jig or template on the end of the femur, or thigh bone. This jig allows the surgeon to cut the bone precisely so that the prosthesis fits exactly. Once the femur is cut, the inside of the bone will be prepared so that it closely matches the shape of the femoral shaft your surgeon has selected. Then the cup portion of the pelvis is prepared with cutting tools so that the metal cup will fit exactly.
For other patients, the implants are able to be affixed to the bones without cement. Special surgical instruments are used to precisely prepare the bones so as to enable a press fit. To supplement this joining, supportive screws or pegs are often used. Bone is a living and growing tissue. If an implant coated with metallic beads to form a porous undersurface is placed in very close contact to living bone, tissues can grow into the pores, further locking the implant in place. Porous-coated hip prostheses have been used for many years and have shown excellent results in many patients. Finally, the incision is closed, a drain is put in, and the post-operative bandaging is applied.
Computer-Assisted Hip Replacement (CAS)
Hip arthroplasty, as it is officially known, involves the replacement of the ball and socket joint — the ball is the round-tipped, uppermost portion of the femur, and the socket, known as the acetabulum, is a forward-positioned, cup-like indentation in the pelvis. Hip arthroplasty has been practiced worldwide for decades, and has been refined to the point where hundreds of thousands of people who undergo it every year are returning to a life of pain-free mobility.
The new solution
Computer-assisted surgery helps surgeons obtain the most accurate implant alignment and position by providing them with an advanced convergence of multiple medical technologies. Smith & Nephew's computer-assisted hip replacement software helps surgeons visualize bony structures beyond what they can easily see through the incision and it helps them take critical measurements throughout the procedure that are not possible without the assistance of computers.
Before beginning the procedure, the surgeon uses the computer to locate specific anatomic landmarks and to take critical measurements of the patients anatomy. Once the computer has this basic information, it can track the precise position of the patient's leg and pelvis, the implant, and the surgeon's instruments at all times during the procedure. Throughout the procedure, the computer provides constant feedback and information to the surgeon. Do not fear; your surgeon is in charge and does the work. The computer simply puts together all of the information coming in from the patient and the instruments and tells the surgeon when he has achieved his desired placement.
Patient Benefits
A surgeon armed with these tools has the potential to achieve better outcomes and as computer-assisted total hip replacement surgery evolves, surgeons will be better able to perform less invasive procedures due to the enhanced visualization of the surgical site.
A smaller incision made during hip surgery means less muscle is cut and less blood is lost. In turn, this leads to shorter hospital stays and shorter rehabilitation for patients.
• The increased visualization provided by the procedure facilitates minimally invasive surgery. This means a shorter scar, less physical therapy and a faster return to your normal life
• Precise alignment and placement of the implant may extend its lifespan by reducing uneven wear, thus preventing future corrective surgeries
• Precise placement of the acetabular component may help reduce the risk of post-operative dislocation, and more accurate placement contributes to better long-term implant stability and increased range of motion
The Equipment
The Arrays
"Arrays" are metal prongs with small reflective spheres at their extremities. These devices attach to the surgical instruments and to the patients pelvis. Once they are fixed in place, their positions in space are tracked throughout the procedure. That way, the computer will know exactly where the instruments are in relation to the patient's bones, based on where the spheres are at any given second.
The Camera
The camera emits infrared light that reflects off the spheres connected to the arrays. It collects this reflected infrared light, and sends the information about the location of the source of the reflection (the spheres on the arrays)
to the computer.
The computer receives information about where the spheres are in space, and combines that data with three-dimensional virtual images of the orthopaedic implants and surgical instruments.
The Software
The software displays the virtual images of the instruments, implants, and bones on the computer screen, and guides the surgeon through each step of the procedure.
Surgery Day
When you and your orthopedic surgeon decide that total hip replacement is right for you, here is an idea of what you may expect during the days and weeks leading up to surgery, as well as the day of surgery.
You and your orthopedic surgeon may participate in an initial surgical consultation. This appointment may include preoperative X-rays, a complete medical and surgical history, physical examination, and comprehensive list of medications and allergies. During this visit, your orthopedic surgeon will likely review the procedure and answer any questions you may have.
Your orthopedic surgeon may require that you have a complete physical examination by your internist or family physician as you will need to be cleared medically by your physician before undergoing this extensive procedure. And you may be instructed by your internist on whether you need to donate blood prior to surgery in the event that you will need a blood transfusion post-operatively. Also, your orthopedic surgeon may ask you to consult a physical therapist to discuss the recovery period, rehabilitation program, and important precautions, as well as instruct you in exercises that you can begin prior to surgery that will make the recovery much easier.
Your physician and hospital may also require that you visit the admissions department prior to surgery to pre-certify the procedure with your insurance company.
Finally, maintaining good physical health prior to surgery will also improve the recovery period and overall post-operative outcome.
Preparation for the hospital
You may want to bring the following items to the hospital for your hip replacement surgery:
You should follow your regular diet on the day before your surgery. DO NOT EAT OR DRINK AFTER MIDNIGHT. Follow your doctor's instructions regarding use of medication in the days leading to surgery. Finally, try to get a long, restful night's sleep.
Day of surgery
On the morning of the surgery, you will be admitted to the hospital and taken to the appropriate pre-surgical area. The nurse will spend a few minutes preparing you for surgery by taking your vital signs, starting IV fluids, and administering medications as needed. You will be asked to empty your bladder just prior to surgery, and to remove all jewelry, contacts, dentures, etc. You will change into a hospital gown, be placed on a stretcher, and transported to the operating room. The anesthesiologist will meet you and review the medications and procedures used during the surgical case.
After the surgical case is completed, you will be taken to the recovery room for a period of close observation. Your blood pressure, heart rate, respiration, and body temperature will be closely monitored by the recovery room staff. Special attention will be given to your circulation and sensation
in the feet and legs. When you awaken and your condition is stabilized, you will be transferred to your room.
Although the protocols may vary from hospital to hospital,
you may awaken to some or all of the following:
1. A large dressing applied to the surgical area.
2. A hemovac suction container with tubes leading directly into the surgical area. This device allows the nurses to measure and record the amount of drainage being lost from the wound following surgery.
3. An IV will continue post-operatively in order to provide adequate fluids. The IV may also be used for administration of antibiotics
or other medications.
4. A catheter may have been inserted into your bladder as the side effects of medication often make it difficult to urinate.
5. An elastic hose may be applied to decrease the risk of deep vein thrombosis (DVT). Furthermore, a compression device may be applied
to your feet to further prevent a DVT.
6. A patient-controlled analgesia or PCA device may be connected to your IV. This device allows you to control the relative amount and frequency of the pain medication. The unit is set to deliver a predefined amount
of pain medication anytime you press the button of the machine. The machine is programmed so that you cannot overdose on the pain medication.
You will typically be placed on a floor of the hospital with other patients who have had surgical procedures. As a result, the nursing staff is well-trained to manage the post-operative program following total hip replacement.
You will be discharged when you can get out of bed on your own and walk with a walker or crutches, walk up and down three steps, bend your knee 90 degrees and straighten your knee.
At home you should begin ambulation with a cane as tolerated. Keep your incision clean and dry and watch closely for any signs of infection. You'll continue your home exercise program and go to outpatient physical therapy, where you will work on an advanced strengthening program and such programs as stationary cycling, walking, and aquatic therapy.
Your long-term rehabilitation goals are a range of motion from 100-120 degrees of knee flexion, mild or no pain with walking or other functional activities, and independence in all activities of daily living.
Post-Op Care
Thrombophlebitis
This condition, also commonly referred to as deep vein thrombosis, occurs when blood clots are formed in the large veins of the legs. In some cases, these clots can become dislodged from the veins, travel through the circulatory system, and become stuck in the critical arteries of the lungs.
This scenario, called a pulmonary embolism, is a serious medical condition. The following steps may be taken by you and your physician to avoid or prevent thrombophlebitis:
1. Blood-thinning medication (anticoagulants, aspirin)
2. Elastic stockings (TED hose)
3. Foot elevation to prevent swelling
4. Foot and ankle exercises to optimize blood flow
5. Pneumatic devices placed on the feet to improve circulation
IMPORTANT: If you develop swelling, redness, pain and/or tenderness in the calf muscle, report these symptoms immediately to your physician.
Infection
Infections occur in a small percentage of patients undergoing hip replacement surgery. Unfortunately, infections can occur even when every effort is made to prevent them.
1. Closely monitor the incision and immediately report and signs of redness, swelling, tenderness, drainage, foul odor, increasing pain,
or persistent fever.
2. Always wash your hands before and after handling your incision site, especially when the sutures are still in place.
Pneumonia
A possible side effect of surgery is the development of pneumonia.
The following steps may help minimize this risk.
1. Deep breathing exercises: A simple analogy to illustrate proper deep breathing is to: "smell the rose and blow out the candles." In other words, inhale slowly and deeply through your nose, and exhale slowly through your mouth at a slow and controlled rate. A simple rule of thumb may be to perform these deep breathing exercises 8-10 times every waking hour.
2. Coughing: This activity helps to loosen the secretions in your lungs and excrete them from your pulmonary system.
3. Incentive spirometer: This simple device provides visual feedback while performing deep breathing exercises. Your nurse or respiratory therapist will demonstrate the proper technique.
Hip Dislocation
One of the most common problems following total hip replacement is hip dislocation or subluxation. Because the prosthetic ball and socket are smaller than the natural anatomy, the ball can become dislodged from the socket if the hip is placed in certain positions. The following precautions must be taken to prevent hip dislocation.
1. Do not bend forward to reach your feet. You must no bend your hips at greater than a 90-degree angle.
2. Do not bend forward to reach your feet. You must no bend your hips at greater than a 90-degree angle.
3. Do not lift your knee higher than your hip on the operated side.
4. Do not cross your legs.
5. Do not allow your legs to internally rotate (feet turned in).
6. Do not twist while lying or standing.
7. Sleep on your back with a pillow between your knees
to prevent crossing.
For more detailed information regarding the prevention of hip dislocation, refer to the hip rehabilitation section.
Rehabilitation
Hip replacement surgery is a very complex procedure. However, the outcomes following hip replacement are usually very successful. One of the important critical success factors for a successful outcome is following the physical rehabilitation process. In order to help achieve the goals for a successful total hip replacement, you must actively participate in the rehab process and work diligently on your own, as well as the physical therapists, to achieve optimal results.
Your recovery program usually begins the day after surgery.
The rehabilitation team will work together to provide the care and encouragement needed during the first few days after surgery.
The physical therapist will begin as early as 1-2 days after surgery. They will teach you some simple exercises to be done in bed that will strengthen the muscles in the hip and lower extremity. These exercises may include:
1. Gluteal sets: Tighten and relax the buttock muscles.
2. Quadricep sets: Tighten and relax the thigh muscles.
3. Ankle pumps: Flex and extend the ankles.
Your physical therapist will also teach you proper
techniques to perform such simple tasks as:
1. Moving up and down in bed.
2. Going from lying to sitting.
3. Going from sitting to standing.
4. Going from standing to sitting.
5. Going from sitting to lying.
Although these are simple activities, you must learn to do them safely so that the hip does not dislocate or suffer other injury.
Another important goal for early physical therapy is for you to learn to walk safely with an appropriate assistive device (usually a walker or crutches). Your surgeon will determine how much weight you can bear on your new hip, and your therapist will teach you the proper techniques for walking on level surfaces and stairs with the assistive device. Improper use of the assistive device raises the chance for accident or injury.
The occupational therapist will also visit with you to teach you how to perform activities of daily living safely. They will provide you with a list of hip precautions which are designed to protect your new hip during the first 8-12 weeks following surgery.
Precautions:
1. Do not bend forward to reach your feet. You must maintain a 90 degree angle between your torso and legs.
2. Do not lift your knee higher than your hip on the operated side.
3. Do not cross your legs.
4. Do not allow your legs to internally rotate (feet turned in).
5. Do not twist while lying or standing.
6. Sleep on your back with a pillow between your knees to prevent crossing.
7. Strictly observe your weight bearing precautions during
standing or walking.
Also, the occupational therapist will instruct you in the proper use of various long-handled devices for activities of daily living. These devices may include the following:
1. A reacher to dress and pick things up from the floor.
2. A sock-aid that will assist in putting on socks.
3. A long-handled sponge to wash your legs and feet.
4. A leg-lifting device to move the operated leg in and out of the car or bed.
5. An elevated toilet seat so that you don't violate your hip precautions when using the bathroom.
6. An elevated bathtub chair to fit in the shower or tub.
The precautions following a total hip replacement must be strictly adhered to in order to prevent dislocation of the hip implant and the possibility of re-operation.
Following surgery, a physical therapist may help you with your rehabilitation protocol. In addition to the exercises done with the therapist, you should continue to work on the hip exercises in your free time. It is also important to continue to walk on a regularly basis to further strengthen your hip muscles. An exercise and walking program helps to enhance your recovery from surgery and helps make activities of daily living easier to mange.
• Ankle pumps
• Quadricep sets
• Gluteal sets
• Heel slides
• Leg lifts
• Knee extension
• Hip abduction
While at home, you will continue to walk with the assistive device unless directed by your surgeon to discontinue use. You must also remember to strictly follow the hip precautions and weight bearing instructions during the first few months following surgery. It is recommended that you not
drive unless you have been approved by your doctor.
Long-term rehabilitation goals
Once you have completed your rehabilitation program, you can expect to be able to perform most activities of daily living with little to no pain or assistance. Patients following total hip replacement routinely are able to walk, dress, bathe, drive, garden, cook, and return to work. Although final outcomes may vary from patient to patient, total hip replacement surgery is one of the most successful procedures in modern medicine and most patients return to a full and active life.
After Surgery
Once you have completed the post-operative rehabilitation process, you should have near normal range of movement and adequate strength in your hip to perform most activities of daily living.
Because total hip arthroplasty is one of the most successful procedures in modern medicine, you can expect to return to a high level of function. However, special precautions should be taken by people with hip replacements.
Patients having total hip replacement surgery have successfully returned to such activities as walking, driving, swimming, golf, doubles tennis, stationary cycling, and gardening.
Remember to listen to what your body tells you. If you begin to have pain or swelling for over 24-48 hours, contact your healthcare professional for advice.
How long will your implant last
It is difficult to predict the length of time a total hip implant will last as its lifespan depends on many factors. Unfortunately, surgical complications can occur and in some cases implants last only a short time. However, the vast majority of implants last for years, providing patients with pain relief and improved function. By following hip precautions and moderating your activity level, you may enhance the function and longevity of your artificial hip.
Surgeons, researchers and implant manufacturers continue to work diligently to improve both the short term and long term outcomes of total hip replacement. For example, OXINIUM* technology from Smith & Nephew is a new high performance material shown to reduce acetabular component wear by as much as 60-percent. Less implant wear may extend the life of the implant and reduce the need for future corrective surgeries.
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