Arthritis Of The Knee

Knee Anatomy

The knee is the largest joint in the body. A healthy knee moves easily, allowing you to walk, turn, and squat without pain. A complex network of bones, cartilage, ligaments, muscles, and tendons work together to make a knee flexible.

Your knee joint is made up of three bones. Your thigh bone (femur) sits on top of your shin bone (tibia). When you bend or straighten your knee, the rounded end of your thigh bone rolls and glides across the relatively flat upper surface of your shin bone. The third bone is often called the kneecap (patella), which is attached to the muscles that allow you to straighten your knee. Your kneecap provides leverage that reduces strain on these muscles.

Ligaments (another type of soft tissue) lie along the sides and back of the knee, holding the bones of the knee joint in place. These ligaments work with the muscles that control the bones, and the tendons that connect the muscles to the bones, so you can bend and straighten your knee. Fluid-filled sacs (bursae) cushion the area where skin or tendons glide across bone. The knee also has a lining (synovium) that secretes a clear liquid called synovial fluid. This fluid lubricates the joint, further reducing friction and making movement easier.

Three basic types of arthritis may affect the knee joint.

1. Osteoarthritis (OA) is the most common form of knee arthritis. OA is usually a slowly progressive degenerative disease in which the joint cartilage gradually wears away. It most often affects middle-aged and older people.
2. Rheumatoid arthritis (RA) is an inflammatory type of arthritis that can destroy the joint cartilage. RA can occur at any age. RA generally affects both knees.
3. Post-traumatic arthritis can develop after an injury to the knee. This type of arthritis is similar to osteoarthritis and may develop years after a fracture, ligament injury or meniscus tear.

Symptoms of arthritis
Generally, the pain associated with arthritis develops gradually, although sudden onset is also possible. The joint may become stiff and swollen, making it difficult to bend or straighten the knee. Pain and swelling are worse in the morning or after a period of inactivity. Pain may also increase after activities such as walking, stair climbing or kneeling. The pain may often cause a feeling of weakness in the knee, resulting in a "locking" or "buckling." Many people report that changes in the weather also affect the degree of pain from arthritis.

Making the diagnosis
Your doctor will perform a physical examination that focuses on your walk, the range of motion in the limb, and joint swelling or tenderness. X-rays typically show a loss of joint space in the affected knee. Blood and other special imaging tests such as an MRI may be needed to diagnose RA.

Treatment options
In its early stages, arthritis of the knee is treated with conservative, nonsurgical measures.

• Lifestyle modifications can include losing weight, switching from running or jumping exercises to swimming or cycling, and minimizing activities such as climbing stairs that aggravate the condition.
• Exercises can help increase range of motion and flexibility as well as help strengthen the muscles in the leg.
• Using supportive devices such as a cane, wearing energy-absorbing shoes or inserts, or wearing a brace or knee sleeve can be helpful.
• Other measures may include applications of heat or ice, water exercises, liniments or elastic bandages.
• Avoiding squatting,sitting on your knees(namaz position or vajrasan position) and cross legged position.

Several types of drugs can be used in treating arthritis of the knee. Because every patient is different, and because not all people respond the same to medications, your orthopaedic surgeon will develop a program for your specific condition.

• Anti-inflammatory medications can include aspirin, acetaminophen or ibuprofen to help reduce swelling in the joint.
• Glucosamine and chondroitin (kon-dro'-i-tin) sulfate are oral supplements may relieve the pain of osteoarthritis.
• Corticosteroids are powerful anti-inflammatory agents that can be injected into the joint.
• Hyaluronate (hi-a-lou'-ron-ate) therapy consists of a series of injections designed to change the character of the joint fluid.
• Special medical treatments for RA include gold salt injections and other disease-modifying drugs.

Surgical Treatment
If your arthritis does not respond to these nonoperative treatments, you may need to have surgery.

• Arthroscopic surgery uses fiber optic technology to enable the surgeon to see inside the joint and clean it of debris or repair torn cartilage.
• An osteotomy cuts the shinbone (tibia) or the thighbone (femur) to improve the alignment of the knee joint.
• A total or partial knee arthroplasty replaces the severely damaged knee joint cartilage with metal and plastic.
• Cartilage grafting is possible for some knees with limited or contained cartilage loss from trauma or arthritis.

Orthopaedic surgeons are continuing to search for new ways to treat arthritis of the knee. Current research is focusing on new drugs as well as on cartilage transplants and other ways to help slow the progress of arthritis.

Nonsurgical Treatment Options for Osteoarthritis of the Knee

If you have osteoarthritis of the knee (OA Knee), you can take advantage of a wide range of treatment options. Only one in four people with OA Knee need surgery, but the effectiveness of different treatments varies from person to person. The choice of treatment should be a joint decision between you and your physician.

The purpose of treatment is to reduce pain, increase function and generally reduce your symptoms. Patient satisfaction is a fundamental goal in treating OA Knee. Treatment options can be nonsurgical or surgical. Nonsurgical treatments fall into four major groups:

• Health and behavior modifications, such as physical therapy and exercise, weight loss and education
• Drug therapy, such as pain relievers Intra-articular (within the joint) treatments, such as injections

Here is some information about various nonsurgical treatment options that you might want to discuss with your physician.

Health and behavior modifications
Health and behavior modifications include:

• Patient education
• Physical therapy and exercise
• Weight loss
• Use of a knee brace

The more you understand about your condition, the better prepared you are to make decisions about your care. Patient education focuses on understanding the disease, learning about treatment options, and working with your physician to develop exercise and pain management programs suited to your life. It is based on the belief that your personal actions and behavior changes can reduce the impact of the disease. Your visit to this Web site shows your interest in learning about your condition.

Physical therapy and exercise are often effective in reducing pain and improving function. Your physician or a physical therapist can help develop an individualized exercise program that meets your needs and lifestyle. Many, but not all, people with OA Knee are overweight. Simple weight loss can reduce stress on weightbearing joints, such as the knee. Losing weight can result in reduced pain and increased function, particularly in walking. Some research studies have focused on the use of knee braces for treatment of OA Knee. They may be especially helpful if the arthritis is centered on one side of the knee. A brace can assist with stability and function. There are two types of braces that are often used. An "unloader" brace shifts load away from the affected portion of the knee. A "support" brace helps support the entire knee load. In most studies, the knee symptoms improved, with a decrease in pain on weightbearing and a general ability to walk longer distances.

Drug treatments
Several types of drugs are used to treat OA Knee. Among these are:

• Simple pain relievers
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• COX-2 inhibitors
• Glucosamine/chondroitin sulfate

Simple pain relievers such as Tylenol/crocin/panadol are available without a prescription and can be very effective in reducing pain. Pain relievers are usually the first choice of therapy for OA Knee. All drugs have potential side effects and simple analgesics are no exception. In addition, with time, your body can build up a tolerance, reducing the effects of the pain reliever. It is important to realize that these medications, although purchased over-the-counter, can also interact with other medications you are taking, such as blood-thinners. Be sure to discuss these issues with your orthopaedist or primary physician.

A more potent type of pain reliever is a nonsteroidal anti-inflammatory drug or NSAID. These drugs, which include brands such as Motrin, Advil and Aleve,or locally voveran,brufen,combiflamm are available in both over-the-counter and prescription forms. Like all pain relievers, NSAIDs can cause side effects including changes in kidney and liver function as well as a reduction in the ability of blood to clot. These effects are usually reversible when the medication is discontinued.
 
Glucosamine and/or chondroitin sulfate may be particularly helpful in the early stages of OA Knee, provided they are used as directed on package inserts and with caution. These are two large molucules that are found in the cartilage of our joints.

These substances can help reduce swelling and tenderness, as well as improve mobility and function. If you decide to take this therapy, it is important not to discontinue too soon. At least two months of continuous use is necessary before the full effect is realized.

Intra-articular treatments
"Intra-articular" means within the joint itself. These treatments involve one or more injections into the knee joint. There are two types of intra-articular treatments:

• Corticosteroid injections
• Viscosupplementation with hyaluronic acid

Corticosteroid injections are given for moderate to severe pain. They can be very useful if there is significant swelling, but are not very helpful if the arthritis affects the joint mechanics. Corticosteroids or cortisone are natural substances known as hormones. They are produced by the adrenal glands in the human body. They can provide pain relief and reduce inflammation with a subsequent increase in quadriceps (thigh muscle) strength. However, the effects are not long-lasting, and no more than four injections should be given per joint per year.

In addition, there is some concern about the use of these injections. For example, pain and swelling may "flare" immediately after the injection, and the potential exists for long-term joint damage or infection. With frequent repeated injections or over an extended period of time, joint damage can actually increase rather than decrease.

Viscosupplementation is a way of adding fluid to lubricate the joint and make it easier to move. This substance is a concentrate of hyaluronic acid, a molecule that is found in the joints of the body. There is less fluid in a knee with osteoarthritis than in a healthy knee. Three to five weekly shots are needed to reduce the pain, but the pain relief is not permanent. Many patients experience improvement for weeks to months, however, and find the process highly worthwhile.

Viscosupplementation can be helpful for people whose arthritis has not responded to behavior modification or basic drug treatments. It is most effective if the arthritis is in its early states (mild to moderate). Sometimes, patients feel pain at the injection site, and occasionally the injections result in an increase in pain and swelling.

Alternative therapies
Alternative therapies include the use of acupuncture and magnetic pulse therapy. Many forms of therapy are unproven, but reasonable to try, provided you find a qualified practitioner and keep your physician informed of your decisions.

Acupuncture is adapted from a Chinese medical practice. It uses fine needles to stimulate specific body areas to relieve pain or temporarily numb an area. Although it is used in many parts of the world and evidence suggests that it can help ease the pain of arthritis, there are few scientific studies of its effectiveness. Studies that have been done seem to indicate that acupuncture is better at relieving pain than at improving function. The most common risk is the potential for infection and disease transmission from the use of nonsterile needles. Be sure your acupuncturist is certified, and do not hesitate to ask about his or her sterilization practices.

Magnetic pulse therapy is another alternative that may be helpful in reducing the pain of OA Knee. It's painless and works by applying a pulsed signal to the knee, which is placed in an electromagnetic field. Because the body produces electrical signals, scientists think that magnetic pulse therapy may stimulate the production of new cartilage. However, like many alternative therapies, magnetic pulse therapy has yet to be proven. Before attempting any therapy on your own, talk to your physician. Together, you can develop a program that will increase your understanding of arthritis, help ease your pain and improve the functioning of your joints.

Surgical Treatment of Osteoarthritis of the Knee

The first line of treatment for osteoarthritis of the knee (OA Knee) is nonsurgical. However, if conservative treatment does not relieve pain and improve function, your physician may recommend surgery. About one in four people with OA Knee will eventually need surgery. The choice of treatment should be a joint decision between you and your physician.

The purpose of surgical treatment for OA Knee is to reduce pain, increase function and improve your symptoms overall. Patient satisfaction is a fundamental goal in treating OA Knee. Surgical treatments options include:

• Arthroscopy
• Osteotomy
• Arthroplasty

Arthroscopy
Arthroscopy is a surgical procedure that uses small incisions and miniature instruments. A tiny telescope (arthroscope) is inserted into the joint space, which is then filled with fluids so the surgeon can clearly see the components of the joint. This enables the surgeon to look directly at the bone surfaces and to determine how advanced your arthritis is.

Using tiny instruments, the surgeon can trim damaged cartilage, remove any loose particles or debris from the joint (a procedure called debridement) and clean the joint (a process called "lavage" or "irrigation"). If other problems are discovered, such as a torn meniscus (a C-shaped piece of cushioning in the knee) or a damaged ligament, they can be corrected during the same surgery.

Arthroscopy can be helpful if your joint pain results from a tear in the cartilage or meniscus, or if bits of debris are causing problems in bending or straightening the joint. In people under age 55, arthroscopic surgery may help delay the need for more serious surgery such as a joint replacement. As with any surgery, there are some risks due to the use of anesthesia and the possibility of infection. Other complications may include damage to nerves or blood vessels, the development of blood clots in veins and scarring.

Arthroscopy is not the best option for everyone. Although the puncture wounds are small and pain is minimal, it takes several weeks for the joint to recover fully. Your physician will prescribe a specific activity and rehabilitation program to encourage recovery and protect future function of the joint.

Osteotomy
An osteotomy may be recommended if damage to your knee cartilage is primarily in one section (compartment) of the knee. The inside (medial) compartment, where the inner knob of the thighbone (femoral condyle) meets the top of the shinbone (tibia), is most commonly involved. An osteotomy also may be recommended if a broken knee does not heal properly. This procedure involves reshaping the bones to improve knee alignment. The surgeon repositions the joint to move the mechanical axis of weightbearing for the limb away from the damaged area. This shifts weightbearing stresses from the damaged section to a healthier part of the knee. An osteotomy can restore knee function and diminish osteoarthritis pain. It may even stimulate the growth of new cartilage. Although an osteotomy can decrease pain and improve function, the results often deteriorate over the long term. Many people who have an osteotomy will eventually need a total knee replacement (arthroplasty). As with all surgeries, there is a slight possibility of infection, complications from the anesthesia or other surgical complications such as blood clots, nerve damage and circulation problems. There will be a cosmetic difference between the surgically-treated knee and the untreated knee.

Arthroplasty An arthroplasty is a joint replacement procedure. If your OA Knee pain is severe and significantly limits your movement, your physician may recommend that the diseased bone and tissue be replaced by an artificial joint. If your arthritis is localized to one side of the knee, your orthopaedic surgeon may recommend a unicompartmental knee arthroplasty. If both sides of the knee are affected, a total joint replacement may be more appropriate. The replacment parts are made of cobalt-chrome or titanium metals and smooth, wear-resistant plastic (polyethylene).

The results of total joint replacement are generally excellent. Patients experience significant pain relief and improved physical functioning. There are some risks to the surgery, and full rehabilitation may take three to six months. In addition, the prosthesis (artificial joint) may eventually loosen or wear out so that a second surgery is needed. However, at the 10-year mark, the success rate with most prostheses today is about 90 percent.

Your orthopaedic surgeon should discuss the type of knee replacement, the type of surgery (minimal incision or standard incision), the potential risks and the rehabilitation protocol with you before you make your decision.

Total Knee Replacement

If your knee is severely damaged by arthritis or injury, it may be hard for you to perform simple activities such as walking or climbing stairs. You may even begin to feel pain while you're sitting or lying down.

If medications, changing your activity level and using walking supports are no longr helpful, you may want to consider total knee replacement surgery. By resurfacing your knee's damaged and worn surfaces, total knee replacement surgery can relieve your pain, correct your leg deformity and help you resume your normal activities. One of the most important orthopaedic surgical advances of the twentieth century, knee replacement was first performed in 1968. Improvements in surgical materials and techniques since then have greatly increased its effectiveness. Approximately 300,000 knee replacements are performed each year in the United States. Whether you have just begun exploring treatment options or have already decided with your orthopaedic surgeon to have total knee replacement surgery, this booklet will help you understand more about this valuable procedure.
How the Normal Knee Works The knee is the largest joint in the body. Nearly normal knee function is needed to perform routine everyday activities. The knee is made up of the lower end of the thigh bone (femur), which rotates on the upper end of the shin bone (tibia), and the knee cap (patella), which slides in a groove on the end of the femur. Large ligaments attach to the femur and tibia to provide stability. The long thigh muscles give the knee strength. The joint surfaces where these three bones touch are covered with articular cartilage, a smooth substance that cushions the bones and enables them to move easily. All remaining surfaces of the knee are covered by a thin, smooth tissue liner called the synovial membrane. This membrane releases a special fluid that lubricates the knee, reducing friction to nearly zero in a healthy knee. Normally, all of these components work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness and less function.
Common Causes of Knee Pain and Loss of Knee Function The most common cause of chronic knee pain and disability is arthritis. Osteoarthritis, rheumatoid arthritis and traumatic arthritis are the most common forms. Osteoarthritis usually occurs after the age of 50 and often in an individual with a family history of arthritis. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness. Rheumatoid Arthritis is a disease in which the synovial membrane becomes thickened and inflamed, producing too much synovial fluid that over-fills the joint space. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain and stiffness. Traumatic Arthritis can follow a serious knee injury. A knee fracture or severe tears of the knee's ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.

Is Total Knee Replacement for You?
The decision whether to have total knee replacement surgery should be a cooperative one between you, your family, your family physician and your orthopaedic surgeon. Your physician may refer you to an orthopaedic surgeon for a thorough evaluation to determine if you could benefit from this surgery. Alternatives to traditional total knee replacement surgery that your orthopaedic surgeon may discuss with you include a unicompartmental knee replacement or a minimally invasive knee replacement.

Reasons that you may benefit from total knee replacement commonly include:

Severe knee pain that limits your everyday activities, including walking, going up and down stairs, and getting in and out of chairs. You may find it hard to walk more than a few blocks without significant pain and you may need to use a cane or walker. Moderate or severe knee pain while resting, either day or night Chronic knee inflammation and swelling that doesn't improve with rest or medications Knee deformity--a bowing in or out of your knee Knee stiffness--inability to bend and straighten your knee Failure to obtain pain relief from non-steroidal anti-inflammatory drugs. These medications, including aspirin and ibuprofen, often are most effective in the early stages of arthritis. Their effectiveness in controlling knee pain varies greatly from person to person. These drugs may become less effective for patients with severe arthritis. Inability to tolerate or complications from pain medications Failure to substantially improve with other treatments such as cortisone injections, physical therapy, or other surgeries

Most patients who undergo total knee replacement are age 60 to 80, but orthopaedic surgeons evaluate patients individually. Recommendations for surgery are based on a patient's pain and disability, not age. Total knee replacements have been performed successfully at all ages, from the young teenager with juvenile arthritis to the elderly patient with degenerative arthritis.

The Orthopaedic Evaluation
The orthopaedic evaluation consists of several components:

A medical history, in which your orthopaedic surgeon gathers information about your general health and asks you about the extent of your knee pain and your ability to function A physical examination to assess your knee motion, stability, strength and overall leg alignment X-rays to determine the extent of damage and deformity in your knee Occasionally blood tests, a Magnetic Resonance Image (MRI) or a bone scan may be needed to determine the condition of the bone and soft tissues of your knee. Your orthopaedic surgeon will review the results of your evaluation with you and discuss whether total knee replacement would be the best method to relieve your pain and improve your function. Other treatment options--including medications, injections, physical therapy, or other types of surgery--also will be discussed and considered. Your orthopaedic surgeon also will explain the potential risks and complications of total knee replacement, including those related to the surgery itself and those that can occur over time after your surgery.
Realistic Expectations About Knee Replacement Surgery An important factor in deciding whether to have total knee replacement surgery is understanding what the procedure can and can't do. More than 90 percent of individuals who undergo total knee replacement experience a dramatic reduction of knee pain and a significant improvement in the ability to perform common activities of daily living. But total knee replacement won't make you a super-athlete or allow you to do more than you could before you developed arthritis. Following surgery, you will be advised to avoid some types of activity, including jogging and high impact sports, for the rest of your life. With normal use and activity, every knee replacement develops some wear in its plastic cushion. Excessive activity or weight may accelerate this normal wear and cause the knee replacement to loosen and become painful. With appropriate activity modification, knee replacements can last for many years.
Preparing for Surgery Medical Evaluation If you decide to have total knee replacement surgery, you may be asked to have a complete physical by your family physician several weeks before surgery to assess your health and to rule out any conditions that could interfere with your surgery. Tests Several tests-such as blood samples, a cardiogram and a urine sample-may be needed to help your orthopaedic surgeon plan your surgery.

Preparing Your Skin and Leg
Your knee and leg should not have any skin infections or irritation. Your lower leg should not have any chronic swelling. Contact your orthopaedic surgeon prior to surgery if either of these conditions is present for a program to best prepare your skin for surgery.

Blood Donation
You may be advised to donate your own blood prior to the surgery. It will be stored in the event you need blood after your surgery.

Medications
Tell your orthopaedic surgeon about the medications you are taking. He or she will tell you which medications you should stop taking and which you should continue to take before surgery. Usually pain medications and blood thinners are discontinued a week prior.

Dental Evaluation
Although the incidence of infection after knee replacement is very low, an infection can occur if bacteria enter your bloodstream. Treatment of significant dental diseases (including tooth extractions and periodontal work) should be considered before your total knee replacement surgery.

Urinary Evaluations
A preoperative urological evaluation should be considered for individuals with a history of recent or frequent urinary infections. For older men with prostate disease, required treatment should be considered prior to knee replacement surgery.

Social Planning
Though you will be able to walk on crutches or a walker soon after surgery, you will need help for several weeks with such tasks as cooking, shopping, bathing and doing laundry. If you live alone, your surgeon's office and a social worker or a discharge planner at the hospital can help you make advance arrangements to have someone assist you at home.

Home Planning
Several suggestions can make your home easier to navigate during your recovery. Consider:

• Safety bars or a secure handrail in your shower or bath
• Secure handrails along your stairways
• A stable chair for your early recovery with a firm seat cushion (height of 18-20 inches), a firm back, two arms, and a footstool for intermittent leg elevation
• A toilet seat riser with arms, if you have a low toilet
• A stable shower bench or chair for bathing
• Removing all loose carpets and cords

• A temporary living space on the same floor, because walking up or down stairs will be more difficult during your early recovery

Your Surgery You will most likely be admitted to the hospital on the day prior to your surgery. After admission, you will be evaluated by a member of the anesthesia team. The most common types of anesthesia are general anesthesia, in which you are asleep throughout the procedure, and spinal or epidural anesthesia, in which you are awake but your legs are anesthetized. The anesthesia team will determine which type of anesthesia will be best for you with your input. The procedure itself takes about two hours. Your orthopaedic surgeon will remove the damaged cartilage and bone and then position the new metal and plastic joint surfaces to restore the alignment and function of your knee.

Many different types of designs and materials are currently used in total knee replacement surgery. Nearly all of them consist of three components: the femoral component (made of a highly polished strong metal), the tibial component (made of a durable plastic often held in a metal tray), and the patellar component (also plastic).

After surgery, you will be moved to the recovery room, where you will remain for one to two hours while your recovery from anesthesia is monitored. After you awaken, you will be taken to your hospital room.

Unicompartmental Knee Replacement
Although not as common as total knee replacement, the partial or unicompartmental knee replacement is a viable alternative in limited situations. The designs of the unicompartmental types of knee replacements have improved over the years, as has the sophistication of the instruments used to implant these types of artificial joints. The unicompartmental knee replacement also has smaller, less invasive incisions.

The "uni," as it is commonly called, is used to replace a single compartment of the arthritic knee. The knee joint has three compartments: the medial (inner) compartment, the lateral (outer) compartment and the patellofemoral (kneecap) compartment. If the damage is limited to either the medial or lateral compartment, that compartment may be replaced with the uni.

If two or more compartments are damaged, the uni may not be the best option. The uni is also less desirable for a young, active person because it may not withstand the extremes of stress that high levels of activity create. It is best suited for the older, slim person with a relatively sedentary lifestyle. Only between six and eight out of 100 patients with arthritic knees are good candidates for a unicompartmental knee replacement.

Because the uni can be inserted through a relatively small incision (about 3" or 4" long), which does not interrupt the main muscle controling the knee, rehabilitation is faster, hospitalization is shorter and return to normal activities is more rapid than after a total knee replacement.
However, this is still a serious operation, which has all the same risks as total knee replacement. These risks, as well as whether you are a good candidate for the uni, should be discussed with your orthopaedic surgeon.

Minimally Invasive Total Knee Replacement

Description
Total knee replacement (arthroplasty) is a surgery that is performed for severe degeneration of the knee joint. More than 300,000 people undergo the procedure each year. Minimally invasive total knee arthroplasty is one method of performing a knee replacement. It uses a smaller incision. Knees wear out for a variety of reasons. These include inflammation from arthritis, injury or simple wear and tear. A knee replacement is the resurfacing of the worn out surfaces of the knee. A surgeon replaces lost cartilage with metal and plastic. This is typically done through an incision down the center of the knee. The incision averages 8 inches to 10 inches long. Minimally invasive total knee arthroplasty is a different way of performing the surgery. It uses an incision that is only 4 inches to 6 inches long. This means that potentially there will be less damage to the tissue around the knee.

The minimally invasive knee replacement technique attempts to accomplish all of this through a smaller incision. With the smaller incision come the potential benefits of a shorter hospital stay, a shorter recovery and a better looking scar. There is no reason to believe that the knee will function any better. Although there is no question that a knee can be put in through a smaller incision, it is still unknown whether it can be done as well. New ways to open the knee may be more important than the length of the incision. These are sometimes called "quad-sparing" because they protect the quadriceps (the muscle on the front of the thigh) and make the recovery easier.

Several early studies of MIS knee surgery have shown some benefits such as less blood loss, shorter hospital stays and better motion, while others have shown a higher rate of complications, suboptimal positioning of the knee implants and no real difference in the recovery. Unfortunately, we won't know if these new techniques affect the long-term function and durability of the knee replacement for 10 to 15 years. Long-term durability is much more important than whether you were in the hospital for 2 days or 4 days after surgery.

Research on the Horizon/What's New?
Advocates of minimally invasive knee replacement are working to address concerns about accurate positioning of the knee replacement. They are combining the small incision with computer-guided instruments. This reduces the complication rate of minimal access surgery.

Minimally Invasive Knee Replacement
A recent advance in the performance of total knee replacement is the use of minimally invasive approaches. This technique, still in its relative infancy, is more challenging than standard total knee replacement. The incisions are approximately half the size of those used in a standard approach. The smaller incisions and new techniques to expose the joint may result in short-term advantages such as a quicker rehabilitation, possibly less pain and a shorter hospitalization.

The minimally invasive approach to the total knee replacement is appropriate for non-obese patients who have reasonable motion without significant deformity. Hospitalization may be reduced to one to three days among these patients, and the need for an extended stay for inpatient rehabilitation may be reduced or eliminated in most patients.

Although some studies show shorter hospitalizations and rehabilitation periods, other studies find minimally invasive surgery to be no better than standard techniques. The risks are not well known, but are probably comparable to those for a standard total knee replacement. Speak to your orthopaedic surgeon about whether you might be an appropriate candidate for this particular approach to total knee replacement.

Rotating Platform/Mobile-bearing Knees

Fixed- vs. mobile-bearing
Most people get a fixed-bearing prosthesis that reduces knee pain dramatically and may last for many years. Knee prostheses consist of three component parts that function together as a system:

• Femoral: a polished, strong metal shell on the lower end of the thighbone.
• Tibial: a high-density polyethylene piece on top of a metal tray.
• Patellar: a high-density polyethylene piece replacing the underside of the kneecap in the center of the knee.

In certain cases, excessive activity and extra weight can accelerate the process of wear to parts of a fixed-bearing prosthesis, causing it to loosen from the bone and become painful. Loosening is a major reason some artificial joints fail.
If you are younger, more active and/or overweight, sometimes a doctor may recommend a rotating platform/mobile-bearing knee replacement designed for potentially longer performance with less wear. Doctors also consider gender, occupation, disability level, pain intensity, interference with lifestyle and other medical conditions in selecting the appropriate prosthesis.

Difference is bearing surface
Like fixed-bearing replacements, mobile-bearing knees use three components to provide a relatively natural and even interface. The difference is the bearing surface. In a mobile-bearing knee replacement, both the metallic femoral component and metallic tibial tray move across a polyethylene insert to create a dual-surface articulation. The insert absorbs forces across a larger contact surface, helping reduce the amount of wear to the bearing and loosening in places where the prosthesis attaches to bone.

Advantages: Mobile-bearing knee replacements can reduce early wear failure caused by high contact stress and early loosening failure caused by over-constraint. The insert's mobility ensures congruent contact between the femoral and tibial components and conformity of the surfaces that move together when you bend and rotate your knee during activity. The mobile-bearing insert lets you move the knee from both the thighbone and shinbone. You can also rotate the shinbone slightly.

Disadvantages: Compared with fixed-bearing designs, mobile-bearing knee implants are less forgiving of imbalance in soft tissues. They may increase the chance of dislocation and may cost more than fixed-bearing implants.

Cemented and Cementless Knee Replacement

Cemented designs use a fast-curing bone cement (polymethylmethacrylate) to hold the prostheses in place. Cementless designs rely on bone growing into the surface of the implant for fixation.

Cemented Fixation
The majority of knee replacements done today are cemented into place. Cemented knee replacements have a generally excellent track record and may last more than 20 years. The longevity and performance of a knee replacement depends on several factors, including activity level, weight and general health.

Cemented fixation relies on a stable interface between the prosthesis and the cement as well as a solid mechanical bond between the cement and the bone. Today's metal alloy components rarely break, but they can occasionally come loose from the bone. Two processes, one mechanical and one biological, can contribute to loosening.

1. During natural movement, the knee is subject to considerable loads and stresses, which the prostheses must transfer to the underlying bone. Because the hard subchondral bone of the shinbone (tibia) is removed during a knee replacement, loads are absorbed by the softer cancellous bone and the peripheral cortical bone that remains. If loads are heavier than the underlying bone can bear over a long period of time, the prosthesis will begin to sink into or loosen from its attachment to the bone. Additionally, if the load applied to the knee during walking is uneven, one side of the implant may "lift off" the bone as the other side is pressed into it, resulting in uneven wear of the polyethylene liner between the metal components. This wear creates debris particles of polyethylene that can trigger a biologic response and further contribute to loosening of the implant and sometimes to bone loss around the implant.
2. The microscopic debris particles are absorbed by cells around the joint and initiate an inflammatory response from the body, which tries to remove them. This inflammatory response can also cause cells to remove bits of bone around the implant, a condition called osteolysis. As wear continues, so does the bone loss. The bone weakens, and the loosening of the implant from bone increases. Despite these recognized failure mechanisms, the bond between cement and bone is generally very durable and reliable. Cemented TKA has been used successfully in all patient groups for whom total knee replacement is appropriate, including young and active patients with advanced degenerative joint disease.

Cementless Fixation
In the 1980s, implant designs were introduced that were intended to attach directly to bone without the use of cement. These designs have a surface topography that is conducive to attracting new bone growth. Most are textured or coated so that the new bone actually grows into the surface of the implant. They may also use screws or pegs to stabilize the implant until bone ingrowth occurs. Because they depend on new bone growth for stability, cementless implants require a longer healing time than cemented replacements. Some cementless total knee designs have been as successful as cemented designs in relieving pain and restoring function.

However, cementless prostheses have not solved the problems of wear and bone loss. In all knee replacement designs, metal (usually a titanium- or cobalt/chromium-based alloy) rubs against ultrahigh-density polyethylene. Even though the metal is polished smooth and the polyethylene is treated to resist wear, the loads and stresses of daily movements will generate microscopic particulate debris. This debris, in turn, can trigger the inflammatory response that results in osteolysis.

Because cementless prostheses have not been used for as long as cemented prostheses, comparisons of long-term use is not possible. However, short-term outcome studies generally showed that cementless TKA has success rates comparable to cemented TKA.

Hybrid TKA
In a hybrid TKA, the femoral component is inserted without cement, and the tibial component is inserted with cement. This technique was introduced in the early 1980s; long-term results are just now being measured and are generally positive.

Outcomes
Knee replacement operations, whether they use cemented or cementless fixation, are highly successful in relieving pain and restoring movement. However, the ongoing problems with wear and particulate debris may eventually necessitate further surgery, including replacing one or more parts of the knee replacement (revision surgery).

Knee Implants

More joint replacement surgeries (arthroplasties) are performed on the knee than on any other joint. In a total knee arthroplasty (TKA), the diseased cartilage surfaces of the thighbone (femur), the shinbone (tibia) and the kneecap (patella) are replaced by prostheses made of metal alloys, high-grade plastics and polymeric materials. Most of the other structures of the knee, such as the connecting ligaments, remain intact.

Knee replacement surgery is generally recommended for patients with severe knee pain and disability caused by damage to cartilage from rheumatoid arthritis, osteoarthritis or trauma. It is highly successful in relieving pain and restoring joint function.
 
There are more than 150 knee replacement designs on the market today. Several manufacturers make knee implants. The brand and design used by your doctor or hospital depends on many factors, including your needs (based on your age, weight, activity level and health), the doctor's experience and familiarity with the device, and the cost and performance record of the implant. You may wish to discuss these issues with your doctor.

Implant Construction
The metal parts of the implant are made of titanium- or cobalt/chromium-based alloys. The plastic parts are made of ultrahigh-density polyethylene. All together, the components weigh between 15 and 20 ounces, depending on the size selected. The construction materials used must meet several criteria:

• They must be biocompatible; that is, they can function in the body without creating either a local or a systemic rejection response.
• Their mechanical properties must be able to duplicate the structures they are intended to replace; for example, they are strong enough to take weightbearing loads, flexible enough to bear stress without breaking and able to move smoothly against each other as required.
• They must be able to retain their strength and shape for a long time. The chance of a knee replacement lasting 15 to 20 years is about 95 percent.

To date, man-made joints have not solved the problem of wear. Every time bone rubs against bone, or metal rubs against plastic, the friction creates microscopic particulate debris. Just as wear in the natural joint contributed to the need for a replacement joint, wear in the prostheses may eventually require a second (revision) surgery.

Implant Insertion
During a TKA, the knee is in a bent position so that all the surfaces to be replaced can be exposed. The usual approach is lengthwise through the front of the knee, just to the inside of the kneecap, although some surgeons will approach the joint from the outer side, just above the kneecap. The incision is 4 to 6” long. The large quadriceps muscle and the kneecap are moved to the side to reveal the bone surfaces.

After taking several measurements to ensure that the new implant will fit properly, the surgeon begins to smooth the rough edges of the bones. Depending on the type of implant used, the surgeon may begin with either the thighbone or the shinbone.

Special jigs are used to accurately trim the damaged surfaces at the end of the thighbone. The devices shape the end of the thighbone so it configures to the inside of the prosthesis. The shinbone is cut flat across the bone and a portion of the bone's center is drilled out. The surgeon removes just enough of the bone so that when the prosthesis is inserted, it recreates the joint line at the same level as prior to surgery. If any ligaments around the knee have contracted due to pain and deformity before the surgery, the surgeon carefully releases them so that they function as close to the normal state as possible.

The prostheses are inserted, tested and balanced. The surgeon wants to be sure that the joint line is in the right place and the kneecap is accurately aligned for proper joint movement. If it is necessary to resurface the kneecap, the surgeon will apply a shaped piece of polyethylene that maintains the original width of the kneecap.

Your Stay in the Hospital You will most likely stay in the hospital for several days. After surgery, you will feel some pain, but medication will be given to you to make you feel as comfortable as possible. Pain management is an important part of your recovery, so talk with your surgeon if postoperative pain becomes a problem. Walking and knee movement are important to your recovery and will begin immediately after your surgery. To avoid lung congestion after surgery, you should breathe deeply and cough frequently to clear your lungs. Your orthopaedic 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 your knee and leg, your surgeon may use a knee support that slowly moves your knee while you are in bed. The device, called a continuous passive motion (CPM) machine, decreases leg swelling by elevating your leg and improves your venous circulation by moving the muscles of your leg. Foot and ankle movement also is encouraged immediately following surgery to increase blood flow in your leg muscles to help prevent leg swelling and blood clots. Most patients begin exercising their knee the day after surgery. A physical therapist will teach you specific exercises to strengthen your leg and restore knee movement to allow walking and other normal daily activities soon after your surgery.

Possible Complications After Surgery
The complication rate following total knee replacement is low. Serious complications, such as a knee joint infection, occur in less than 2 percent of patients. Major medical complications such as heart attack or stroke occur even less frequently. Chronic illnesses may increase the potential for complications. Although uncommon, when these complications occur, they can prolong or limit your full recovery.

Blood clots in the leg veins are the most common complication of knee replacement surgery. Your orthopaedic surgeon will outline a prevention program, which may include periodic elevation of your legs, lower leg exercises to increase circulation, support stockings and medication to thin your blood.

Although implant designs and materials as well as surgical techniques have been optimized, wear of the bearing surfaces or loosening of the components may occur. Additionally, although an average of 115 degrees of motion is generally anticipated after surgery, scarring of the knee can occasionally occur and motion may be more limited. This is particularly true in patients with limited motion before surgery. Finally, while rare, injury to the nerves or blood vessels around the knee can occur during surgery.

Discuss your concerns thoroughly with your orthopaedic surgeon prior to surgery.

Your Recovery at Home
The success of your surgery also will depend on how well you follow your orthopaedic surgeon's instructions at home during the first few weeks after surgery.

Wound Care
You will have stitches or staples running along your wound or a suture beneath your skin on the front of your knee. The stitches or staples will be removed several weeks after surgery. A suture beneath your skin will not require removal.
Avoid soaking the wound in water until the wound has thoroughly sealed and dried. The wound may be bandaged to prevent irritation from clothing or support stockings.

Diet
Some loss of appetite is common for several weeks after surgery. A balanced diet, often with an iron supplement, is important to promote proper tissue healing and restore muscle strength.

Activity
Exercise is a critical component of home care, particularly during the first few weeks after surgery. You should be able to resume most normal activities of daily living within three to six weeks following surgery. Some pain with activity and at night is common for several weeks after surgery. Your activity program should include:

• A graduated walking program to slowly increase your mobility, initially in your home and later outside
• Resuming other normal household activities, such as sitting and standing and walking up and down stairs
• Specific exercises several times a day to restore movement and strengthen your knee. You probably will be able to perform the exercises without help, but you may have a physical therapist help you at home or in a therapy center the first few weeks after surgery.

Driving usually begins when your knee bends sufficiently so you can enter and sit comfortably in your car and when your muscle control provides adequate reaction time for braking and acceleration. Most individuals resume driving about four to six weeks after surgery.

Avoiding Problems After Surgery

Blood Clot Prevention
Follow your orthopaedic surgeon's instructions carefully to minimize the potential of blood clots that can occur during the first several weeks of your recovery.
Warning signs of possible blood clots in your leg include:

• Increasing pain in your calf
• Tenderness or redness above or below your knee
• Increasing swelling in your calf, ankle and foot

Warning signs that a blood clot has traveled to your lung include:

• Sudden increased shortness of breath
• Sudden onset of chest pain
• Localized chest pain with coughing

Notify your doctor immediately if you develop any of these signs.

Preventing Infection
The most common causes of infection following total knee replacement surgery are from bacteria that enter the bloodstream during dental procedures, urinary tract infections, or skin infections. These bacteria can lodge around your knee replacement and cause an infection.

For the first two years after your knee replacement, you must take preventive antibiotics before dental or surgical procedures that could allow bacteria to enter your bloodstream. After two years, talk to your orthopaedist and your dentist or urologist to see if you still need preventive antibiotics before any scheduled procedures.

Warning signs of a possible knee replacement infection are:

• Persistent fever (higher than 100 degrees orally)
• Shaking chills
• Increasing redness, tenderness or swelling of the knee wound
• Drainage from the knee wound
• Increasing knee pain with both activity and rest

Notify your doctor immediately if you develop any of these signs.

Avoiding Falls
A fall during the first few weeks after surgery can damage your new knee and may result in a need for further surgery. Stairs are a particular hazard until your knee is strong and mobile. You should use a cane, crutches, a walker, hand rails or someone to help you until you have improved your balance, flexibility and strength.

Your surgeon and physical therapist will help you decide what assistive aides will be required following surgery and when those aides can safely be discontinued.

How Your New Knee Is Different
You may feel some numbness in the skin around your incision. You also may feel some stiffness, particularly with excessive bending activities. Improvement of knee motion is a goal of total knee replacement, but restoration of full motion is uncommon. The motion of your knee replacement after surgery is predicted by the motion of your knee prior to surgery. Most patients can expect to nearly fully straighten the replaced knee and to bend the knee sufficiently to go up and down stairs and get in and out of a car. Kneeling is usually uncomfortable, but it is not harmful. Occasionally, you may feel some soft clicking of the metal and plastic with knee bending or walking. These differences often diminish with time and most patients find these are minor, compared to the pain and limited function they experienced prior to surgery.

Your new knee may activate metal detectors required for security in airports and some buildings. Tell the security agent about your knee replacement if the alarm is activated.

After surgery, make sure you also do the following: Participate in regular light exercise programs to maintain proper strength and mobility of your new knee. Take special precautions to avoid falls and injuries. Individuals who have undergone total knee replacement surgery and suffer a fracture may require more surgery. Notify your dentist that you had a knee replacement. You should be given antibiotics before all dental surgery for the rest of your life. See your orthopaedic surgeon periodically for a routine follow-up examination and X-rays, usually once a year.

What to expect immediately after surgery
Proper pain management is important in your early recovery. Although pain after surgery is quite variable and not entirely predictable, it can be controlled with medication. Initially, you will probably receive pain control medication through an intravenous (IV) connection so that you can regulate the amount of medication you need. Remember that it is easier to prevent pain than to control it. You don't have to worry about becoming dependent on the medication; after a day or two, injections or pills will replace the IV. You will also have to take antibiotics and blood-thinning medication to help prevent blood clots from forming in the veins of your thighs and calves.

You may lose your appetite and feel nauseous or constipated for a couple of days. These are normal reactions. You may be fitted with a urinary catheter during surgery and be given stool softeners or laxatives to ease the constipation caused by the pain medication after surgery. You will be taught to do breathing exercises to prevent congestion from developing in your chest and lungs.

Initially, you will have a bulky dressing around the knee and a drain to remove any fluid build up around the knee. The drain will be removed in a day or two. You may also be wearing elastic hose and, possibly, compression stocking sleeves. These plastic sleeves are connected to a machine that circulates air around your legs to help keep blood flowing normally.

Usually a physical therapist will visit you on the day after your surgery and begin teaching you how to use your new knee. You may be fitted with a continuous passive motion (CPM) machine that will slowly and smoothly straighten and bend your knee. Even as you lie in bed, you can "pedal" your feet and "pump" your ankles on a regular basis to promote blood flow in your legs.

Discharge
Your hospital stay may last from 3 to 7 days, depending on how well you heal after surgery. Before you go home, you will need to meet several goals:

1. Get in and out of bed by yourself
2. Bend your knee approximately 90 degrees, or show good progress in bending your knee
3. Extend (straighten) your knee fully
4. Walk with crutches or a walker on a level surface and to climb up and down 2 or 3 stairs
5. Do the prescribed home exercises

You may experience mild swelling in your leg after you are discharged. Elevating the leg, wearing compression hose and applying an ice pack for 15 to 20 minutes at a time will help reduce the swelling. You may be permitted to take the CPM machine home with you for a few weeks, but this is not a substitute for the prescribed exercises.

You will probably need some help at home for several weeks.. The following tips can make your homecoming more comfortable.

• Rearrange furniture so you can maneuver with a walker or crutches. You may temporarily change rooms (make the living room your bedroom, for example) to avoid using the stairs.
• Remove any throw or area rugs that could cause you to slip. Securely fasten electrical cords around the perimeter of the room.
• Install a shower chair, gripping bar and raised toilet in the bathroom.
• Use assistive devices such as a long-handled shoehorn, a long-handled sponge and a grabbing tool or reacher to avoid bending too far over.

Activities at home
General guidelines for wound care include:

• Keep the area clean and dry. A dressing will be applied in the hospital and should be changed as necessary. Ask for instructions on how to change the dressing before you leave the hospital.
• Do not shower or bathe until the sutures or staples are removed, usually a week to 10 days after surgery. Keep the wound clean and dry.
• Notify your doctor if the wound appears red or begins to drain.
• Take your temperature twice daily and notify your doctor if it exceeds 100.5°F.
• Swelling is normal for the first three to six months after surgery. Elevate your leg slightly and apply ice.
• Calf pain, chest pain or shortness of breath are signs of a possible blood clot. Notify your doctor immediately if you notice any of these symptoms.

Medication. Take all medications as directed. You will probably be given a blood thinner to prevent clots from forming in the veins of your calf and thigh, because these clots can be life-threatening. If a blood clot forms and then breaks free, it could travel to your lungs, resulting in a pulmonary embolism, a potentially fatal condition.

Because you have an artificial joint, it is especially important to prevent any bacterial infections from settling in your joint implant. You should get a medical alert card and take antibiotics whenever there is the possibility of a bacterial infection, such as when you have dental work. Be sure to notify your dentist that you have a joint implant and let your doctor know if your dentist schedules an extraction, periodontal work, dental implant, or root canal work.

Diet. By the time you go home from the hospital, you should be eating a normal diet. Your physician may recommend that you take iron and vitamin C supplements. Continue to drink plenty of fluids and avoid excessive intake of vitamin K while you are taking the blood thinner medication. Foods rich in vitamin K include broccoli, cauliflower, Brussels sprouts, liver, green beans, garbanzo beans, lentils, soybeans, soybean oil, spinach, kale, lettuce, turnip greens, cabbage and onions. Try to limit your coffee intake and avoid alcohol. You should continue to watch your weight to avoid putting more stress on the joint.

Resuming normal activities: Once you get home, you should continue to stay active. The key is to remember not to overdo it! While you can expect some good days and some bad days, you should notice a gradual improvement and a gradual increase in your endurance over the next 6 to 12 months. The following guidelines are generally applicable, but the final answer on each of these issues should come from your doctor.

• Physical therapy exercises: Continue to do the exercises prescribed for at least two months after surgery. Riding a stationary bicycle can help maintain muscle tone and keep your knee flexible. Try to achieve the maximum degree of bending and extension possible.
• Driving: If your left knee was replaced and you have an automatic transmission, you may be able to begin driving in a week or so, provided you are no longer taking narcotic pain medication. If your right knee was replaced, avoid driving for 6 to 8 weeks. Remember that your reflexes may not be as sharp as before your surgery.
• Airport metal detectors: The sensitivity of metal detectors varies and it is unlikely that your prosthesis will cause an alarm. You should carry a medic alert card indicating you have an artificial joint, just in case.
• Sexual relations can be safely resumed approximately 4 to 6 weeks after surgery.
• Sleeping positions: You can safely sleep on your back, on either side, or on your stomach.
• Return to work: Depending on the type of activities you perform, it may be 6 to 8 weeks before you return to work
• Other activities: Walk as much as you like, but remember that walking is no substitute for the exercises your doctor and physical therapist will prescribe. Swimming is also recommended; you can begin as soon as the sutures have been removed and the wound is healed, approximately 6 to 8 weeks after surgery. Acceptable activities include dancing, golfing (with spikeless shoes and a cart), and bicycling (on level surfaces). Avoid activities that put stress on the knee. These activities include: tennis, badminton, contact sports (football, baseball), squash or racquetball, jumping, squats, skiing or jogging. Do not do any heavy lifting (more than 40 pounds) or weight lifting.

Sample Exercises
These exercises will help strengthen the quadriceps muscles on the front of the thigh that stabilize and move the knee.

1. Lie on your back with your arms at your side and your legs straight, together, and flat. Place a rolled towel or small pillow under your ankles to raise your heel slightly. Tighten the muscles on the top of one thigh as you push the back of your knee down toward the floor (bed). Hold for 5 seconds, relax for 5 seconds. Do 10 cycles with each leg.
2. Put a rolled blanket or pillow under your knee so that the knee bends about 30 to 40 degrees. Tighten the muscles on the top of your thigh and straighten the knee by lifting your heel off the floor (bed). Hold 5 seconds, then slowly lower your heel to the floor (bed). Repeat 10 to 20 times.

Knee Replacement Exercise Guide

Regular exercise to restore your knee mobility and strength and a gradual return to everyday activities are important for your full recovery. Your orthopaedic surgeon and physical therapist may recommend that you exercise approximately 20 to 30 minutes two or three times a day and walk 30 minutes, two or three times a day during your early recovery. Your orthopaedist may suggest some of the following exercises. The following guide can help you better understand your exercise/activity program, supervised by your therapist and orthopaedic surgeon.

Early Post-operative Exercises

Start the following exercises as soon as you are able. You can begin these in the recovery room shortly after surgery. You may feel uncomfortable at first, but these exercises will speed your recovery and actually diminish your post-operative pain.

Quad Sets - Tighten your thigh muscle. Try to straighten your knee. Hold for 5 to 10 seconds. Repeat this exercise approximately 10 times during a two minute period, rest one minute and repeat. Continue until your thigh feels fatigued.

	Straight Leg Raises - Tighten the thigh muscle with your knee fully straightened on the bed, as with the Quad set. Lift your leg several inches. Hold for five to 10 seconds. Slowly lower. Repeat until your thigh feels fatigued. You also can do leg raises while sitting. Fully tighten your thigh muscle and hold your knee fully straightened with your leg unsupported. Repeat as above. Continue these exercises periodically until full strength returns to your thigh.
	Ankle Pumps - Move your foot up and down rhythmically by contracting the calf and shin muscles. Perform this exercise periodically for two to three minutes, two or three times an hour in the recovery room. Continue this exercise until you are fully recovered and all ankle and lower-leg swelling has subsided.
	Knee Straightening Exercises - Place a small rolled towel just above your heel so that it is not touching the bed. Tighten your thigh. Try to fully straighten your knee and to touch the back of your knee to the bed. Hold fully straightened for five to 10 seconds. Repeat until your thigh feels fatigued.
	Bed-Supported Knee Bends - Bend your knee as much as possible while sliding your foot on the bed. Hold your knee in a maximally bent position for 5 to 10 seconds and then straighten. Repeat several times until your leg feels fatigued or until you can completely bend your knee.
	Sitting Supported Knee Bends - While sitting at bedside or in a chair with your thigh supported, place your foot behind the heel of your operated knee for support. Slowly bend your knee as far as you can. Hold your knee in this position for 5 to 10 seconds. Repeat several times until your leg feels fatigued or until you can completely bend your knee.
	Sitting Unsupported Knee Bends - While sitting at bedside or in a chair with your thigh supported, bend your knee as far as you can until your foot rests on the floor. With your foot lightly resting on the floor, slide your upper bodies forward in the chair to increase your knee bend. Hold for 5 to 10 seconds. Straighten your knee fully. Repeat several times until your leg feels fatigued or until you can completely bend your knee.

Early Activity

Soon after your surgery, you will begin to walk short distances in your hospital room and perform everyday activities. This early activity aids your recovery and helps your knee regain its strength and movement.

	Walking - Proper walking is the best way to help your knee recover. At first, you will walk with a walker or crutches. Your surgeon or therapist will tell you how much weight to put on your leg. Stand comfortably and erect with your weight evenly balanced on your walker or crutches. Advance your walker or crutches a short distance; then reach forward with your operated leg with your knee straightened so the heel of your foot touches the floor first. As you move forward, your knee and ankle will bend and your entire foot will rest evenly on the floor. As you complete the step, your toe will lift off the floor and your knee and hip will bend so that you can reach forward for your next step. Remember, touch your heel first, then flatten your foot, then lift your toes off the floor.
	Walk as rhythmically and smooth as you can. Don't hurry. Adjust the length of your step and speed as necessary to walk with an even pattern. As your muscle strength and endurance improve, you may spend more time walking. You will gradually put more weight on your leg. You may use a cane in the hand opposite your surgery and eventually walk without an aid. When you can walk and stand for more than 10 minutes and your knee is strong enough so that you are not carrying any weight on your walker or crutches (often about two to three weeks after your surgery), you can begin using a single crutch or cane. Hold the aid in the hand opposite the side of your surgery. You should not limp or lean away from your operated knee.
	Stair Climbing and Descending - The ability to go up and down stairs requires strength and flexibility. At first, you will need a handrail for support and will be able to go only one step at a time. Always lead up the stairs with your good knee and down the stairs with your operated knee. Remember, "up with the good" and "down with the bad." You may want to have someone help you until you have regained most of your strength and mobility. Stair climbing is an excellent strengthening and endurance activity. Do not try to climb steps higher than the standard height (7 inches) and always use a handrail for balance. As you become stronger and more mobile, you can begin to climb stairs foot over foot.

Advanced Exercises and Activities

Once you have regained independence for short distances and a few steps, you may increase your activity. The pain of your knee problems before surgery and the pain and swelling after surgery have weakened your knee. A full recovery will take many months. The following exercises and activities will help you recover fully.

Standing Knee Bends - Standing erect with the aid of a walker or crutches, lift your thigh and bend your knee as much as you can. Hold for 5 to 10 seconds. Then straighten your knee, touching the floor with your heel first. Repeat several times until fatigued.

Assisted Knee Bends - Lying on your back, place a folded towel over your operated knee and drop the towel to your foot. Bend your knee and apply gentle pressure through the towel to increase the bend. Hold for 5 to 10 seconds; repeat several times until fatigued.

Knee Exercises with Resistance - You can place light weights around your ankle and repeat any of the above exercises. These resistance exercises usually can begin four to six weeks after your surgery. Use one- to two-pound weights at first; gradually increase the weight as your strength returns. (Inexpensive wrap-around ankle weights with Velcro straps can be purchased at most sporting goods stores.)

Exercycling - Exercycling is an excellent activity to help you regain muscle strength and knee mobility. At first, adjust the seat height so that the bottom of your foot just touches the pedal with your knee almost straight. Peddle backward at first. Ride forward only after a comfortable cycling motion is possible backwards. As you become stronger (at about four to six weeks) slowly increase the tension on the exercycle. Exercycle for 10 to 15 minutes twice a day, gradually builds up to 20 to 30 minutes, three or four times a week.

Pain or Swelling after Exercise - You may experience knee pain or swelling after exercise or activity. You can relieve this by elevating your leg and applying ice wrapped in a towel. Exercise and activity should consistently improve your strength and mobility. If you have any questions or problems, contact your orthopaedic surgeon or physical therapist.