Total Knee Replacement (Anthroplasty)

What is It?

Knee replacement is a surgical procedure — performed in the U.S. since the 1960s — in which a diseased or damaged joint is replaced with an artificial joint called a prosthesis.Made of metal alloys and high-grade plastics (to better match the function of bone and cartilage, respectively), the prosthesis is designed to move just like a healthy human joint. Over the years, knee replacement techniques and instrumentation have undergone countless improvements. Today, knee replacement is one of the safest and most successful types of major surgery; in about 90% of cases it is complication-free and results in significant pain relief and restoration of mobility.

The knee is the largest joint in the body and is central to nearly every routine activity. The knee joint is formed by the ends of 3 bones: the lower end of the femur (thigh bone), the upper end of the tibia (the shin bone), and the patella (kneecap). Thick, tough tissue bands called ligaments connect the bones and stabilize the joint. A smooth, plastic like lining called cartilage covers the ends of the bones and prevents them from rubbing against each other, allowing for flexible and nearly frictionless movement. Cartilage also serves as a shock absorber, cushioning the bones from the forces between them. Finally, a soft tissue called synovium lines the joint and produces a lubricating fluid that reduces friction and wear.

One of the most common causes of knee pain and loss of mobility is the wearing away of the joint's cartilage lining. When this happens, the bones rub against each other, causing significant pain and swelling — a condition known as osteoarthritis. Trauma or direct injury to the knee can also cause osteoarthritis. Without cartilage there is no shock absorption between the bones in the joint. This allows stress to build up in the bones and contributes to pain.

Knee Anatomy

What are the treatment options?

Each patient is unique, but generally candidates for knee replacement surgery have:

• Pain severe enough to restrict not only work and recreation, but also the routine activities of daily living 
• Pain that is not relieved by more conservative methods of treatment, such as reduced activity, medication or physical therapy 
• Significant joint stiffness and loss of mobility 
• X-rays that show advanced arthritis or other degenerative problems

The National Institutes of Health (NIH) has concluded that knee replacement surgery is "a safe and cost-effective treatment for alleviating pain and restoring function in patients who do not respond to non-surgical therapies." According to the American Academy of Orthopaedic Surgeons, knee replacement procedures have resulted in significant restoration of function and reduction of pain in about 90% of patients. As you read,make a note of anything you don't understand. Your doctor will be happy to answer your questions so that you'll feel comfortable and confident with your chosen treatment plan.

Procedure Goals

A knee replacement should relieve severe pain caused by osteoarthritis. When fully recovered, most patients can expect to return to work — unless your type of work is not advisable for people with artificial joints. Examples of these include construction work, certain types of carpentry, and occupations that involve repeated high climbing or lifting. You should discuss your situation with your doctor.

Risks of the Procedure

The complication rate following joint replacement surgery is very low. Serious complications, such as joint infection, occur in less than 2% of patients. Nevertheless, as with any major surgical procedure, patients who undergo total joint replacement are at risk for certain complications — many of which can be successfully avoided and/or treated.

Possible complications include:

Infection: Infection may occur in the wound or within the area around the new joint. It can occur in the hospital, after the patient returns home, or years later. Following surgery, joint replacement patients receive antibiotics to help prevent infection. Joint replacement patients may also need to take antibiotics before undergoing any medical procedures to reduce the chance of infection spreading to the artificial joint.

Blood Clots: Blood clots can result from several factors, including the patient's decreased mobility following surgery, which slows the movement of the blood. There are a number of ways to reduce the possibility of blood clots, including:

• Blood thinning medications (anticoagulants) 
• Elastic support stockings that improve blood circulation in the legs 
• Plastic boots that inflate with air to promote blood flow in the legs 
• Elevating the feet and legs to keep blood from pooling 
• Walking hourly

Lung Congestion: Pneumonia is always a risk following major surgery. To help keep the lungs clear of congestion, patients are assigned a series of deep breathing exercises.

What to Expect

Your hospital stay will progress something like this:

Pre-Op

1. Arrive at the hospital at the appointed time. 
2. Complete the admission process. 
3. Have final pre-surgery assessment of vital signs and general health. 
4. Remove all personal belongings – dentures, hearing aids, hairpins, wigs, jewelry, glasses, contact lenses, nail polish, all underwear – and leave them with your family or friends during surgery. You will be dressed in a hospital gown and nothing else. 
5. There will be several checks to make sure the correct joint is being replaced: your surgeon will review your X-ray and mark the area to be operated on; nursing staff will check the consent form you signed to make sure it agrees with the procedure on the operating room list. 
6. Final meeting with anesthesiologist and operating room nurse. 
7. Start IV (intravenous) catheter for administration of fluids and antibiotics. 
8. Transportation to the operating room.

In Surgery

Many people will be with you in the operating room during your one to three-hour surgery, including:

• Orthopaedic surgeon(s) – your doctor(s) who will perform surgery. 
• Anesthesiologist or nurse anesthetist – the doctor or nurse who gives you anesthesia. 
• Scrub nurse – the nurse who hands the doctors the tools they need during surgery. 
• Circulating nurse – a nurse who brings things to the surgical team.

Your surgeon and the anesthesiologist or nurse anesthetist will help you choose the best anesthesia for your situation. No matter what type of anesthesia you have, be assured you will not feel the surgery. 

Elastic stockings will be put on your legs to help the blood flow. You may also have compression foot pumps wrapped around your feet and connected to a machine that blows them up with air to promote blood flow and decrease the possibility of blood clots.

On the first day after your surgery, you may get out of bed and begin physical and occupational therapy — typically for several brief sessions a day. These are first steps on your way to getting back into the routines of your life!

In the days following surgery, your condition and progress will continue to be closely monitored by your orthopedic specialist, nurses, and physical therapists. A good deal of time will be given to exercising the new joint, as well as deep-breathing exercises to prevent lung congestion. Gradually, pain medication will be reduced, the IV will be removed, diet will progress to solid food, and you will become increasingly mobile. Every individual is different, and insurance coverage will differ as well. Generally speaking, a total of four days (including the day of the surgery) in the hospital is typical.

Joint replacement patients are generally discharged from the hospital when they are able to achieve certain rehabilitative milestones, such as getting in and out of bed unassisted or walking 100 feet. Your physician will assess your progress and decide whether you are ready to go directly home or to a facility that will assist with your rehabilitation.

Usually a case manager is assigned to work with you as you move through your rehabilitation routines. As the days progress, expect to become more independent using two crutches or a walker.

You will work with a physical therapist after your joint replacement surgery. The therapist will begin an exercise program that you can perform in bed and in the therapy department. The physical therapist will work with you to help you gain confidence and increase your range of motion.

To help you gain confidence with your new joint, the physical therapist (or nurses) will also show you: 

• How to get out of bed 
• How to use the bathroom 
• How to get dressed

Leaving the hospital will depend on when you “graduate” from physical therapy. When you leave the hospital, the physical therapist should give you a list of activities, exercises, and “do’s and don’t’s” to follow. An occupational therapist or nurse may also be assigned to help with special needs. An occupational therapist may show you how to use certain devices that assist in performing daily activities, such as putting on socks, reaching for household items, and bathing.

You shouldn’t be surprised if you feel a little shaky and uncertain for the first day or two after you’re discharged. However, you should soon get a routine going and gain confidence in your new joint — the start of a new life with less pain. (As with any surgery, expect to take pain medication for a few days while you are healing.)

You may need a walker and/or crutches for about six weeks, then a cane for another six weeks or so. Your doctor or orthopaedic specialist as well as your case manager will be in touch with you, so use these opportunities to ask questions or discuss concerns, and keep your team up-to-date on your progress.

The decision to resume a normal daily routine is one that only you and your doctor or orthopedic surgeon can make. However, there are some general guidelines that your doctor may give you.

• You should have no restrictions on leaving your home as long as your safety and comfort are assured. Just don’t tire yourself out; a good balance of exercise, rest, and relaxation is best for helping your body heal and gain strength. 
• You may need to take antibiotics before dental work (including dental cleaning) and any surgical procedure that could allow bacteria to enter the bloodstream. Ask your healthcare provider whether you will need to take antibiotics at certain times to prevent infection. 
• When to resume driving a car, going back to work, and/or participating in sports activities are all highly individualized decisions. Be sure to follow your doctor’s or orthopaedic specialist’s advice and recommendations.

Before Procedure

1. Prepare meals – You may want to prepare meals in advance and freeze them so they’re ready when you return. 
2. Confer with physical therapist – The physical therapist will record a baseline of information, including measurements of current pain levels, functional abilities, the presence of swelling, and available movement and strength. You will also practice post-operative exercises using either a walker or crutches. 
3. Plan for post-surgery rehabilitative care – Total joint replacement recipients may need help at home for the first few weeks, including assistance bathing, dressing, preparing meals and with transportation. If you can’t arrange for someone to help you at home, you may need to stay in a rehabilitation or skilled nursing facility. A medical social worker can assist with arrangements. Home therapy visits should end when you can safely leave the house and outpatient physical therapy should begin. 
4. Fast the night before – No eating or drinking after midnight before surgery; however, you may brush your teeth or have a few sips of water if you need to take medicines. Discuss the need to take medications such as insulin, heart or blood pressure pills with your doctor or nurse to make sure you don’t miss them. 5. Bathe surgical area with antiseptic solution – Use antiseptic scrub brushes supplied by your health team the night before and morning of to reduce the risk of infection. Tell the nurse if you are allergic to iodine or soap. If possible, shampoo your hair. You must remove all nail polish and make-up. Do not shave your legs within 3-4 days of surgery.

After Procedure

You may also be advised to avoid certain activities, including some athletics, as they may place excessive stress your new joint. Examples of these activities include:

• Skiing (snow or water) 
• Basketball 
• Baseball 
• Contact sports 
• Distance running 
• Frequent jumping

The success of your joint replacement will strongly depend on how well you follow your orthopedic surgeon’s instructions. As time passes, you will potentially experience a dramatic reduction in joint pain and a significant improvement in your ability to participate in daily activities. Remember, however, that joint replacement surgery will not allow you to do more than you could before you developed your joint problems.

It’s important to have realistic expectations. For example, artificial joints have limitations: 

• Excessive joint “loading” because of the patient being overweight or strenuous activity, such as running and hiking, may injure the artificial joint. 
• The artificial joint will not restore function to the same level as normal, healthy bone. 
• The life span of the artificial joint is not infinite. It cannot be expected to equal that of normal, healthy bone. 
• Adverse effects may result in a need for additional surgery, including revision or removal of the artificial joint.

Most people experience reduction in joint pain and improvement in their quality of life following joint replacement surgery. While joint replacement surgery may allow you to resume many daily activities, don’t push your implant to do more than you could before your problem developed. Give yourself at least six weeks following surgery to heal and recover from muscle stiffness, swelling and other discomfort. Some people continue to experience discomfort for 6-12 weeks following their joint replacement.

During visits to the physical therapist’s office, your therapist may use heat, ice or electrical stimulation to reduce any remaining swelling or pain. You should continue to use your walker or cane as instructed. Your physical therapist may use hands-on stretches for improving range of motion. Strength exercises address key muscle groups, including the buttock, hip, thigh and calf muscles. You can work on endurance through stationary biking, lap swimming and using an upper body ergometer (upper cycle). Physical therapists sometimes treat their patients in a pool. Exercising in a swimming pool puts less stress on your joints and the buoyancy lets you move and exercise easier. When you are safe putting full weight through the leg, several types of balance exercises can help you further stabilize and control the hip or knee. Finally, you will work with a group of exercises to simulate day-to-day activities, such as going up and down steps, squatting, rising up on your toes, bending down and walking on uneven terrain. You may be given specific exercises to simulate your particular work or hobby demands.

By six weeks, you may be able to return to many normal activities such as driving, bicycling and golf. When you see your surgeon for follow-up two to six weeks after surgery, he or she can advise you on both short and long-term goals.

Rehabilitation Plan- Exercises

Low Impact Aerobic Exercise – Swimming and riding a stationary bike are great low impact exercises that help build strength in your knee. Stop any exercise that causes increasing pain.

Short-Arc Knee Extensions – Roll up several towels in a roll 6-8 inches thick. Lay in bed with the towels under one knee. Bend the other knee. Keeping your knee on the towels, lift your foot to straighten the knee. Hold for a few seconds and lower the foot.

Ankle Pumps – While lying in bed, point your toes downward and then bring your toes back up towards your head, tightening your calf.

Heel Slides – Slide your heel along the bed pulling your foot towards you as your knee bends.

Straight Leg Raise – Start by tightening your quadriceps, the muscles in the front of your thigh. Then with toes toward the ceiling, lift your leg 6-12 inches from the bed.

Quadriceps Sets – Lie on your back, legs straight. Tighten the muscle in the front of your thigh as you press the back of your knee toward the bed. Hold for a few seconds, then relax the leg.

Standing Knee Bends – Stand while holding onto a steady surface, such as a table. Bend your knee as far as it will go comfortably. Hold for a few seconds and lower the leg.

Increasing upper body strength is also important because of the need to use a walker or crutches after knee replacement.

Bicep Curls – In a sitting position, keep you elbow close to your body and your wrist straight. Bend you arm, moving your hand up to your shoulder, then lower slowly.

Triceps Extensions – Sit, leaning forward from the waist. Bend your elbow so that your forearm is parallel to the floor. Then straighten your elbow as you extend your arm behind you.

Seated Press Ups – Sit in a sturdy chair with armrests. With palms on the armrests, press down to lift yourself from the chair. Hold for 3-5 seconds. Bend your elbows slowly to ease back down.

Talk to your doctor before starting any exercise program and remember to call your doctor if you experience increased pain or swelling in your knee after exercise.