JOINT REPLACEMENT: KNOW YOUR KNEE
Total knee replacement is a surgical procedure in which parts of
an arthritic or damaged knee are removed and replaced with a metal and a
polyethylene device called prosthesis. The prosthesis is designed to replicate
the movement of a normal, healthy joint.
When is a ‘Total Joint Replacement’ recommended?
If nonsurgical treatments, such as medications, physical therapy, and changes to your everyday activities do not relieve your pain and disability, your doctor may recommend a total joint replacement.
The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis, most knee pains are caused mainly by three types: Osteoarthritis, Rheumatoid Arthritis, and Post- Traumatic Arthritis.
This is an age-related ‘wear and tear’ type of arthritis. It usually occurs in people 50 years of age and older but may also occur in younger people.
This occurs when the synovial membrane that surrounds the joint becomes inflamed and thickened. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness.
This can follow a serious knee injury. Fractures of the bones surrounding the knee or tears of the knee ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.
CANDIDATES FOR SURGERY
There are no absolute age or weight restrictions for a total knee replacement surgery. Recommendations for surgery are based on a patient’s pain and disability, not age. Most patients who undergo total knee replacement are between 50 to 80 years of age, but orthopaedic surgeons evaluate patients individually. Total knee replacements have been performed successfully at all ages, from the young teenager with juvenile arthritis to the elderly patient with degenerative arthritis.
More than 90 percent of people, who have total knee replacement surgery, experience a dramatic reduction of knee pain and a significant improvement in the ability to perform common activities of daily living. Realistic activities following total knee replacement include unlimited walking, swimming, driving, biking, and other low-impact sport.
With appropriate activity modification, knee replacements can last many years.
PREPARING FOR SURGERY
If you decide to have a total knee replacement surgery, you need to do certain tests several weeks before the operation. This is needed to make sure you are healthy enough to have the surgery and complete the recovery process. Many patients with chronic medical conditions, such as heart disease, may also be evaluated by a specialist like a cardiologist before the surgery.
Several tests, such as blood and urine samples, and an electrocardiogram, may be needed to help your orthopaedic surgeon plan your surgery.
Although the incidence of infection after knee replacement is low, an infection can occur if bacteria enter your bloodstream. To reduce the risk of infection, major dental procedures (such as tooth extractions and periodontal work) should be completed before your total knee replacement surgery.
People with a history of recent or frequent urinary infections should have a urological evaluation before surgery. Older men with prostate disease should consider completing required treatment before undertaking knee replacement surgery.
The most common types of anesthesia are spinal, epidural, or regional nerve block anesthesia (you are awake but your body is numb from the waist down) or general anesthesia. The anesthesia team, with your input, will determine which type of anesthesia will be best for you.
The procedure itself takes approximately 1 to 11/2 hours. Your orthopaedic surgeon will remove the damaged cartilage and bone, and then position the new metal and plastic implants to restore the alignment and function of your knee.
After surgery, you will be moved to the recovery room, where you will remain for several hours while your recovery from anesthesia is monitored. After you wake up, you will be taken to your critical care room.
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.
Some loss of appetite is common for several weeks after surgery. A balanced diet, often with an iron supplement, is important to help your wound heal and to restore muscle strength.
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 3 to 6 weeks following surgery. Some pain with activity and at night is common for several weeks after surgery. You can do the following:
A graduated walking programme to slowly help increase your mobility, initially within the confines of your home and later outside.
Resumption of other normal household activities, such as sitting, standing, and climbing 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.
Infection may occur in the wound or deep around the prosthesis. It may happen while in the hospital or after you go home. It may even occur years later. Minor infections in the wound area are generally treated with antibiotics. Major or deep infections may require more surgery and removal of the prosthesis. Any infection in your body can spread to your joint replacement.
Blood clots in the leg veins are one of the most common complications of knee replacement surgery. These clots can be life-threatening if they break free and travel to your lungs. The prevention programme may include periodic elevation of your legs, lower-leg exercises to increase circulation, support stockings, and medication to thin your blood.
Deep Vein Thrombosis
Blood clots may form in one of the deep veins of the body. While blood clots can occur in any deep vein, they most commonly form in the veins of the pelvis, calf, or thigh.
Although implant designs and materials, as well as surgical techniques, continue to advance, implant surfaces may wear down and the components may loosen. Additionally, although an average of 115° of motion is generally anticipated after surgery, scarring of the knee can occasionally occur, and motion may be more limited, particularly in patients with limited motion before surgery.
A small number of patients continue to have pain after a knee replacement. This complication is rare, however, and the vast majority of patients experience excellent pain relief following knee replacement.
While rare, injury to the nerves or blood vessels around the knee can occur during surgery.
How Your New Knee Is Different
Improvement of knee motion is one of the key goals of total knee replacement, but restoration of full motion is uncommon. The motion of your knee replacement after surgery can be predicted by the range of motion you have in your knee before surgery.
Most patients can expect to be able to almost fully straighten the replaced knee and to bend the knee sufficiently to climb stairs and get in and out of a car. Kneeling can sometimes be uncomfortable, but not harmful.
Most people feel some numbness in the skin around your incision. You also may feel some stiffness, particularly with excessive bending activities.
Most people also feel or hear some clicking of the metal and plastic with knee bending or walking.
This is a normal. These differences often diminish with time and most patients find them to be tolerable when compared with 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 programmes to maintain proper strength and mobility of your new knee.
- Take special precautions to avoid falls and injuries. If you break a bone in your leg, you may require more surgery.
- See your orthopaedic surgeon periodically for a routine follow up examination and x-rays, usually once a year.
EXTENDING THE LIFE OF YOUR KNEE IMPLANT
Currently, more than 90 percent of modern total knee replacements are still working well 15 years after surgery. Following your orthopaedic surgeon’s instructions after surgery and taking care to protect your knee replacement and your general health are important ways you can contribute to the final success of your surgery.