Frequently Asked Questions about Hip and Knee Replacement (Arthroplasty)
General Arthritis & Joint Replacement Questions
Questions about Hip Replacement
Questions about Before and After Hip Surgery
Technical Questions about Hip Replacements
Frequently Asked Questions about Knee Replacement (Knee arthroplasty)
Questions about Knee Replacement (Arthroplasty)
Questions about Before and After Knee Surgery
Frequently Asked Questions about Hip and Knee Replacement (Arthroplasty)
General Arthritis Questions
Arthritis is one of the most common causes of joint pain. There are many types of arthritis, including:
General Questions about Hip Replacement
The hip is a ball and socket joint. The ball is the large, round upper end of the thighbone (femur). This fits into a cuplike socket (acetabulum) on the outer side of your pelvis, or hipbone.
The bones of the hip joint are covered with a layer of cartilage, a smooth, tough tissue that keeps the bones from rubbing together. (You've probably seen cartilage on the end of a chicken drumstick.) Muscles and ligaments (tough bands of tissue) surround the joint and hold the ball in place inside the socket.
What are the symptoms of hip arthritis?
Symptoms tend to get worse over time. However, you may have good months and bad months, and your symptom may change with the weather.
The most common symptoms of hip arthritis are:
What is a total hip replacement?
Total hip replacement (or arthroplasty) is surgery to replace the ball and socket of the hip joint. First the surgeon removes the top part of the thighbone (femur). He or she replaces this with an artificial ball, usually made of metal. This attaches to the top of a metal stem, which fits inside the thighbone.
Next, the surgeon removes some bone from the hip socket, along with any cartilage that remains. A new socket is put in its place. The new ball fits into the new socket, so that the joint can move smoothly, without causing pain.
When should I think about having a hip replacement?
The decision to have this surgery is a "quality of life" choice. Many people have it when they find they can no longer do the things they used to enjoy. When hip pain keeps you from basic activities—like walking, shopping or recreational activities such as bike riding —you may want to consider surgery.
You and your surgeon will make this decision together after considering:
How long will my new joint last?
If you will have a hip replacement, your new joint will be chosen to meet your particular needs. Though it will be made of the most durable materials available, it will eventually wear out if you live long enough.
Studies show that, in people over 65, the first hip replacement will last at least 10 years in 90 to 95 percent of patients. It will last at least 20 years in 80 to 85 percent of patients.
Some factors may shorten the lifespan of an artificial hip joint. For example, the new hip may not last as long in someone who:
What are the risks of hip replacement surgery?
As with any surgery, hip replacement carries some risk. Problems can happen either early or late after surgery. Serious problems are uncommon, but they do occur.
Early complications include:
Late complications include:
Questions about before and after hip surgery
What will I need to do before surgery?
After you schedule the surgery, you will need to see your family doctor for a physical exam. We urge you to also attend a free joint replacement class at the hospital. The class will explain how to prepare for surgery and what to expect before and after.
How long will I be in the hospital?
The average hospital stay is around two to four days, but every patient is different. When leaving the hospital, most patients can go back home if they have someone there who can help them. Some may need to spend a few days at a rehab center. Usually there is no need for a long-term stay in a nursing home.
What medicines will I take after leaving the hospital?
Besides the medicines you were taking before the surgery, you will take:
How long does it take to recover?
This varies with each person. You will use a walker for about four weeks after surgery. You can drive a car in four to eight weeks.
Most people increase their activities slowly. They can often play golf, doubles tennis or go bowling in twelve weeks. More active sports, such as singles tennis and jogging, are not recommended.
How much time will I need to take off work?
It depends on the type of work you do. If you work at a desk, you may be able to return to work in three to six weeks after surgery. If your work is physically demanding, it may be as long as three months.
What type of therapy will I have after surgery?
Right after surgery, getting out of bed and taking your first few steps will be a challenge, but after that it gets easier. Patients who have hip replacements often need much less physical therapy than those who have knee replacements.
You will work with a physical therapist while you are in the hospital. Few patients need physical therapy after they leave.
Walking will be the most important activity for your recovery. In the hospital you will learn how to use a walker. We will tell you whether to put full or partial weight on the hip. When you feel stronger, you can advance to walking with a cane. You should use either crutches or a cane for the next six weeks.
What about stitches, wound care and showers?
You may have staples, metal clips or black stitches closing your wound. These should be removed 10 to 14 days after surgery. You might also have a suture (a stitch that looks like a clear fishing line) sticking out from your incision. You may cut this flush with the skin (like trimming a hair) around one week after surgery. Or, it will fall off on its own in one to two months.
You will wear a bandage over your wound for about one week after surgery. You may take it off once the wound is dry (when there is no blood or fluid oozing from the wound). You may remove the white strips of tape (Steri-Strips) when they start curling up off the skin.
Most people can shower after leaving the hospital. You must wait until the drain tube has been removed and the wound is dry without any fluid oozing from the incision.
When will I need to come back to the clinic or hospital?
Your first follow-up visit will be one month after surgery. At that time, we will ask you to stop taking your blood-thinning medicine (Coumadin). We will X-ray your hips and check how well the wound is healing.
In most cases, if there are no issues that require monitoring by your surgeon, you will schedule your next visit one year from your surgery date.
How can I protect my new hip after surgery?
You will need to protect your hip to prevent the ball from coming out of the socket. For the first 3 months after surgery, you should:
We will go over these and other rules before you leave the hospital.
Remember, your new hip will be less stable than a normal hip. After three months, the soft tissue around the hip will heal and grow strong enough to gradually allow more motion and flexibility.
Technical questions about hip replacements
What is hip resurfacing arthroplasty?
With a traditional total hip replacement, the surgeon removes the entire ball and the top 3- to 4-inches of the thigh bone. The surgeon will also remove the bone inside the canal of an additional 6- to 8-inches of upper thigh bone. This is to make room for the artificial stem. With a hip resurfacing replacement, only the cartilage surface is removed, sparing much more of the bone. Surgeons remove the least possible amount of bone, then reshape the ball and socket. Resurfacing is analogous to re-treading a car tire instead of replacing the entire wheel and tire. The new ball is larger than that used in a traditional total hip replacement and more closely matches the natural joint. This results in a greater range of movement.
Preserving bone is most attractive to young, active patients who are likely to outlive their first hip replacement >and eventually require a new one. A second (revision) hip replacement is easier and has greater durability when there's more original bone present. But resurfacing is not right for everyone. Sometimes the head of the thighbone is too damaged to hold the resurfacing component.
What is the difference between traditional and minimally invasive surgery?
Traditional hip replacement usually uses a 6-to-8-inch incision. The length depends on the size of the patient. This type of surgery has been done for over 40 years. The success rate is above 90 percent even 10 years after surgery.
"Minimally invasive" hip replacement is new since around 2003. There is no accepted definition of "minimally invasive"—it means different things to different surgeons. It can mean:
Your choice of surgery is a personal one best made in view of all the facts. At the University of Minnesota Medical Center, Fairview the size of the incision mainly depends on the amount of space needed to properly place the new joint. This allows us to give you the best, most durable joint possible.
An informative document from an authoritative source (American Association of Hip and Knee Surgeons) is: http://www.aahks.org/pdf/MIS_Patients.pdf
Can both hips be replaced at the same time?
It is possible to replace both hips at the same time. But doing both hips together may increase the risk of surgery and put slightly more stress on your heart and lungs. Surgeons differ in their opinions on this issue.
We recommend doing the second hip one week after the first. Between surgeries, most patients stay in the hospital or spend a few days in a rehabilitation unit.
What is the difference between a cemented and an uncemented joints?
Some replacement joints attach to the bone with cement; others do not. Cemented joints were developed 40 years ago. They are most often used for older, less active people and for people with weak bones, such as those who have osteoporosis (brittle bone disease). Cemented joints are rigidly fixed within the bone immediately after surgery and as such, reduce pain and increase joint mobility. However, they may loosen over time, and cement particles will sometimes break off.
Uncemented joints were developed about 20 years ago in an attempt to increase the durability of the implant's fixation to the natural bone. It is unknown whether cemented or uncemented joints are better or longer-lasting, but most surgeons tend to use uncemented joints in younger patients. Uncemented joints are associated with thigh pain for several months after surgery in 10 to 20 percent of patients. This pain usually resolves spontaneously, but it rare cases it requires a repeat operation.
Doctors will sometimes use a "hybrid" joint, which consists of a cemented >ball and an uncemented >socket. Because each person is unique, the doctor and patient must weigh the advantages and disadvantages to decide which type of joint is best.
What types of materials will be used in my new joint?
Most new joints are made of metal (such as cobalt chrome or a titanium alloy) and plastic (ultra-high molecular-weight polyethylene, highly crosslinked).
Surfaces where the ball and socket rub together are usually made of special plastic, ceramic material or cobalt chrome metal. Most people have a metal surface on the socket and a plastic surface on the ball. This combination has a proven track record of lasting many years in a majority of patients.
Many material surfaces have been tried in the 40 or so years that hip replacements have been done. The most common today include:
The choice of surface is still somewhat controversial. Reasonable scientists, surgeons and patients will sometimes disagree. This is one of the most exciting areas of research in the field of hip replacement surgery. Surgeons consider many factors in selecting implants and understand that only metal-on-plastic surfaces have a widespread, long-term track record longer than 10 years.
Frequently Asked Questions about Knee Replacement (Knee arthroplasty)
General questions about knee replacement (arthroplasty)
The knee is a hinge joint that provides motion where the thigh meets the lower leg. The joint is made up of three bones held together by tough bands of tissue called ligaments. The thighbone (femur) makes up the top part of the joint. It meets the shinbone (tibia) at the lower part of the joint. In front of these bones is the kneecap (patella), a round shield that protects the joint. The kneecap glides in a groove on the end of the thighbone whenever you bend or straighten your leg.
The thighbone and shinbone are separated by cartilage, a smooth, tough tissue that keeps the bones from rubbing together. (You've probably seen cartilage on the end of a chicken drumstick.) The cartilage acts as a cushion. It allows the two bones to move together so you can bend your knee.
What are the symptoms of knee arthritis?
Symptoms tend to get worse over time. However, you may have good months and bad months, and your symptom may change with the weather.
The most common symptoms of knee arthritis are:
What is a total knee replacement (arthroplasty) ?
Total knee replacement, or arthroplasty, is surgery to replace the diseased knee joint. The surgeon removes the bottom of the thighbone (femur) and the top of the shinbone (tibia). He or she re-surfaces the bone ends with metal and plastic. The surgeon may also add a plastic "button" under the surface of the kneecap (patella), if needed.
What is a partial knee replacement (Unicompartmental knee replacement)?
The knee can be divided into three sections, or compartments:
If your knee is damaged only on the inside or outside, but the rest of the knee is healthy, you might be able to have a partial knee replacement. This is sometimes called a unicompartmental knee replacement.
This surgery replaces only the damaged part of your knee. It is much less invasive than total knee replacement. It may require fewer days in the hospital, and recovery time is often much faster.
Can both knees be replaced at the same time?
It is possible to replace both knees at the same time. But doing both knees together may increase the risk of surgery and put slightly more stress on your heart and lungs. Surgeons differ in their opinions on this issue.
We prefer to do the second knee one week after the first. Between surgeries, most patients stay in the hospital or spend a few days in a rehabilitation unit.
When should I think about having a knee replacement?
The decision to have this surgery is a "quality of life" choice. You may want to consider knee replacement when most of the following are true:
You and your surgeon will make this decision together after considering:
What are the risks of knee replacement surgery?
As with any surgery, knee replacement carries some risk. Problems can happen either early or late after surgery. Serious problems are uncommon, but they do occur.
Early complications include:
Late complications include infection and loosening or wearing out of the joint.
How can I lower my risk before and after surgery?
If you smoke, stop! Even quitting the week before surgery will help reduce your risk of lung problems and blood clots.
To further prevent blood clots, you will need to start moving your foot and ankle again right after surgery. We will also give you blood-thinning medicine to help keep blood clots from forming.
Infection is a life-long risk after a knee replacement. An infection causing illness in one part of the body—such as the skin, teeth, respiratory tract or urinary tract—can cause an infection around the new knee joint. If you have any kind of infection, you need to tell your doctor right away.
You will also need to take antibiotics before having dental work or any surgical procedure that could allow germs to enter your bloodstream.
How long will my new joint last?
If you have a knee replacement, your new joint will be chosen to meet your particular needs. Though it will be made of the >most durable materials available, it will eventually wear out if you live long enough.
Studies show that, in people over 65, the first knee replacement will last at least 10 years in 90 to 95 percent of patients. It will last at least 20 years in 80 to 85 percent of patients.
Some factors may shorten the lifespan of an artificial knee joint. For example, the new knee may not last as long in someone who:
Questions about before and after surgery
What will I need to do before surgery?
After you schedule the surgery, you will need to see your family doctor for a physical exam. Your doctor may order several tests, such as blood tests, a urine test and a cardiogram (an ultrasound test to check your heart).
We urge you to also attend a >free joint replacement class at the hospital. The class will explain how to prepare for surgery and what to expect before and after.
How long will I be in the hospital?
The average hospital stay is around two to four days, but every patient is different. When leaving the hospital, most patients can go back home if they have someone there who can help them. Some may need to spend a few days at a rehab center. Usually there is no need for a long-term stay in a nursing home. Physiotherapy is continued after hospital discharge either at an outpatient setting or in the home.
What medicines will I take after leaving the hospital?
Besides the medicines you were taking before the surgery, you will take:
How long does it take to recover?
This varies with each person. Some pain with activity and at night is common for several weeks after surgery. You will be able to go back to most of your daily activities within several weeks. Most people can start driving again once they can bend the knee at least 90 degrees, usually in about four to six weeks.
How much time will I need to take off work?
It depends on the type of work you do. If you work at a desk, you may be able to return to work within a few weeks. If your work is physically demanding, it may be several months.
What type of therapy will I have after surgery?
Right after surgery, getting out of bed and taking your first few steps will be a challenge, but after that it gets easier. Most people begin exercising their knee the day after surgery.
You will work with a physical therapist while you are in the hospital, and you will continue physical therapy after you leave, usually until you can bend the knee at least 90 degrees. Your goal should be to straighten the knee and to bend it 90 degrees within three to four weeks. Your activity program should include:
What about stitches, wound care and showers?
You may have staples, metal clips or black stitches closing your wound. These should be removed 10 to 14 days after surgery. You might also have a suture (a stitch that looks like a clear fishing line) sticking out from your incision. You may cut this flush with the skin (like trimming a hair) around one week after surgery. Or, it will fall off on its own in one to two months.
You will wear a bandage over your wound for about one week after surgery. You may take it off once the wound is dry (when there is no blood or fluid oozing from the wound). You may remove the white strips of tape (Steri-Strips) 10.0pt; mso-bidi-font-family:Arial>when they start curling up off the skin.
Most people can shower after leaving the hospital. You should wait until the drain tube has been removed, the wound is dry and there is no pulling apart of the skin edges.
When will I need to come back to the clinic >or hospital?
Your first follow-up visit will be one month after surgery. At that time, we will ask you to stop taking your blood-thinning medicine (Coumadin). We will X-ray your knee and check how well the wound is healing.
In most cases, if there are no issues that require monitoring by your surgeon, you will schedule your next visit one year from your surgery date.
How can I protect my new knee?
You will always need to protect your new knee. For example, you must not sleep with a pillow under your knee. Instead, you should use an immobilizer or place a pillow under your ankle to keep the knee straight while sleeping.
It will be very important to avoid falling in the first few weeks after surgery. A fall can damage your new knee and lead to more surgery. Until you improve your strength, balance and flexibility, you will need a cane, walker, crutches, handrails or someone to help you. Be very careful on stairs until your knee is strong and mobile.
We will go over these and other safety rules before you leave the hospital.
Will I need assistive devices after knee replacement?
Yes. Assistive devices will make life after surgery more comfortable. Your occupational therapist will help you get the equipment you need. This may include:
You will also need to set up a short-term living space with a bathroom on the same floor. It will be hard to walk up and down stairs early in recovery.
The surgeon may prescribe one or more measures to prevent blood clots and decrease leg swelling, such as special support hose, inflatable leg coverings (compression boots), and blood thinners.
To restore movement in the knee and leg, we use a knee support that slowly moves the knee while in bed starting on the day of surgery. The device, called a continuous passive motion (CPM) machine, decreases leg swelling by elevating the leg and improves the venous circulation by moving the muscles of the leg.
Foot and ankle movement is encouraged immediately following surgery to also increase blood flow in the leg muscles to help prevent leg swelling and blood clots.
For informational purposes only. Not to replace the advice of your health care provider. Copyright © 2005 Edward Y. Cheng, M.D. All rights reserved.