Total Knee Replacement - What You Need to Know

Number of Total Knee Replacements Done Annually in U.S. Is Rising Sharply

Total knee replacement, X-rays
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The first total knee replacement was performed in 1968. The procedure is one of the most important orthopedic surgical advances of the 20th century. Every year in the United States alone, more than 300,000 knee replacements are performed, and the number is expected to increase 525% by the year 2030, according to the March 6, 2008 issue of Time.

The knee replacement prosthesis consists of 3 components: femoral (metal), tibial (plastic in a metal tray), and patellar (plastic).

The prosthesis replaces your damaged knee joint.

Who Needs a Knee Replacement?

Normal knee function is needed to perform almost all of your usual daily activities. Your knee allows you to walk, bend, kneel, and squat.

If your knee has been injured or if it is painful due to arthritis, you will find it difficult to perform daily activities. Osteoarthritis, rheumatoid arthritis, and traumatic arthritis are the three most common types of arthritis that affect the knee joint.

Typically, arthritis patients first try conservative treatments to control knee pain and to try and slow joint damage. If the conservative treatments (medications, injections, braces, physical therapy, heat) are not effective and do not produce a satisfactory response, many patients consider knee replacement as their last-resort treatment option.

The decision to have knee replacement surgery should be made with your family, primary care physician, and orthopedic surgeon.

Consider the following. Do you have:

  • Severe knee pain that limits activities? (walking, climbing stairs, getting in and out of chairs)
  • Moderate to severe knee pain while resting -- day or night?
  • Knee inflammation that is not helped by medications or rest?
  • Knee deformity such as bowing in or out of the knee?

If you answered yes to most or all of the questions, you may be a candidate for knee replacement surgery.

How Is An Individual Patient Evaluated for Knee Replacement?

Most total knee replacement patients are 60 to 80 years old -- but there are patients who are younger or older that do very well following surgery. Each individual patient must be evaluated to determine if knee replacement surgery is their best option.

Patients are evaluated from their medical history -- information about the patient's general health, the extent of knee pain, and severity of physical limitation. A physical examination yields more information about the knee, including range of motion, stability, strength, alignment, and what movements provoke pain. X-rays and other imaging techniques are used to assess joint damage and deformity.

Are Your Expectations About Knee Replacement Realistic?

It's essential for a patient considering knee replacement surgery to understand what to expect from the procedure.

It's important to understand:

  • the ultimate goal of having the surgery which for most patients is pain relief and improved knee function
  • knee replacement surgery does not turn you into the Bionic Man or Woman with super powers
  • you will have certain restrictions after surgery, some being temporary until you have healed and some for the rest of your life
  • knee replacements last many years but may need revision surgery when they wear out or loosen

The majority of knee replacement patients -- upwards of 90% -- have a successful outcome following surgery. Patients typically report dramatic pain relief, and the ability to do daily tasks they have not done easily for a long time.

Even so, there are recommendations for activity levels after surgery.

  • Expected levels of activity after surgery include: recreational walking, swimming, golf, driving, light hiking, recreational biking, ballroom dancing, normal stair climbing
  • Activities that exceed usual recommendations include: vigorous walking or hiking, skiing, tennis, repetitive aerobic stair climbing, repetitive lifting of over 50 pounds
  • Activities that are considered dangerous after surgery include: jogging, running, contact sports, jumping sports, high impact aerobics

Are You Prepared for Surgery?

Your orthopedic surgeon and his staff will guide you through their normal routine for knee replacement. They will assign you a surgery date and give you a schedule for what should be done prior to surgery -- from checking medical insurance to pre-op testing, to autologous blood donation if needed.

Once everything is in order for pre-surgical matters, you will be given information about what to expect during surgery. You will learn about your options for anesthesia, how long the surgery will take, how long you can expect to be in the hospital, and discharge planning.

After surgery or post-op, you will be given rehabilitation instructions or home-going instructions. You will be assessed by physical therapy, occupational therapy, and wound care. Plans will be made according to your needs, but the goal is to have you recover safely, fully, and without complications.

What Are Possible Complications of Knee Replacement?

The complication rate associated with knee replacement surgery is low with serious complications developing in fewer than 2% of patients. Joint infection is considered a serious complication of knee replacement.

The most common complication of knee replacement surgery is blood clots that form in leg veins. Preventative measures are taken to reduce the likelihood of blood clots: elevating legs, exercises to promote circulation in the legs, compression stockings, and blood thinners.

Points to Remember About Knee Replacement

After having a knee replacement, be conscious of certain important aspects of your recovery:

  • Do your post-op exercises as instructed by your physical therapist.
  • Balance rest and activity, especially early in your recovery.
  • Follow instructions to prevent blood clots.
  • Know the signs of infection.
  • Be careful not to fall.
  • Adhere to your restrictions.


Total Knee Replacement. American Academy of Orthopaedic Surgeons. August 2007.

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