MANILA, February 3, 2005 (STAR) AN APPLE A DAY By Tyrone M. Reyes, M.D.  -  The recent successful surgery of former President Estrada highlighted once again the value of total knee replacement in people who have significant arthritis of the knee joint. The pain relief and enhanced function it offers can dramatically improve one’s quality of life. But obviously, total joint surgery is not for everyone. So, like Erap, are you a good candidate for a new knee? Find out by reading on. The Best Solution? We subject our knees to tremendous forces every day – twice our body weight by just walking, and several times our weight when we run or participate in certain sports. These pressures can take a heavy toll. Almost one in four older persons experiences daily knee pain, sometimes, severe enough to make climbing stairs or even walking difficult. And some of those who’ve been athletic all their lives find their activities increasingly curtailed by increasing knee pain. For some, the best solution is to replace the knee with an artificial joint.

Total knee replacement, also known as total knee arthroplasty, relieves pain in 90 to 95 percent of patients. The new joint generally lasts 10 to 15 years before it loosens; at that point, you may need a repeat procedure. A knee replacement will also improve function but won’t necessarily eliminate all problems; many owners of new knees report some difficulty with activities such as squatting, kneeling, and climbing stairs a year or more after surgery. But surgery is recommended mostly on the basis of disability and pain, not age. Most knee replacements are performed at ages 60 to 80, but some studies have shown good results for people even in their 90s.

Osteoarthritis Of The Knee

The leading cause of long-term knee damage and the most common reason for knee replacement is osteoarthritis. It wears down articular cartilage, the tough, flexible tissue that covers and protects the ends of the bones at the joints. Eventually, bone rubs on bone, causing intense pain.

There’s no cure for osteoarthritis. And when conservative treatments are no longer effective or the arthritis has become severe, your clinician may recommend knee replacement if you can’t bend or straighten your knee, can’t walk, or can’t carry out normal daily tasks by yourself, and also if your pain persists despite rest or when pain relievers have unacceptable side effects.

People under 60 are sometimes encouraged to delay the procedure because it’s more likely that they’ll eventually need to replace the implant. (Replacing the implant, or revision surgery, is more difficult because there’s less bone to work with the second time around.) But waiting until symptoms are intolerable may not be a good idea either. Some research suggests that postoperative function is better if you don’t wait too long to undergo surgery.

Before The Operation

Look for a surgeon who has had training in total joint replacement surgery and who does this operation frequently – as well as a hospital where joint replacements are done commonly. You should also meet your physiatrist (medical specialist in Physical Medicine and Rehabilitation), who will manage your postoperative rehabilitation program, and your physical therapist, who will perform your PT treatments. You may undergo physical therapy before surgery so you will know the exercises and training program you will be doing after surgery.

The implant design – there are dozens of them – will depend on your weight, bone quality, age, occupation, and activity level, as well as the surgeon’s experience with a particular model or brand. The components of the artificial knee are hard polished metal and tough slick plastic, ensuring the smoothest movement and the least wear. The metal parts (see illustration) are titanium-based or a cobalt/chromium-based alloy. The plastic parts are ultra-high-density polyethylene.

The surgical procedure is usually scheduled several weeks or months in advance. During that time, you’ll have a complete physical exam to make sure major surgery is safe for you. Because bacteria anywhere in your body can accumulate around a joint replacement and cause an infection, your clinician will monitor you for common infections such as those of the urinary tract or bladder. To guard against bacteria entering the bloodstream, you should complete any necessary dental procedures such as extraction and periodontal work several weeks before surgery. Your knee and leg must also be infection-free.

Your procedure will be safer and your recovery faster if you take a couple of additional steps while awaiting surgery. Try to lose excess weight. This makes rehabilitation easier and will reduce stress on your knee. Improving your upper body strength will make it easier to use crutches. And strengthening your leg muscles will get you on the move sooner. Stopping smoking reduces the risk of postoperative complications.

The Surgery

During the operation, you’re on your back with your knee bent upward. A lengthwise incision six to 12 inches long is made through the front of the knee, and the kneecap and quadriceps muscle are moved to the side. Then, taking care to work around the ligaments, the surgeon makes flat cuts to remove the damaged sections of bone from the lower end of the femur and the top of the tibia. The ends of the bones are then shaped to fit the implant components. Depending on its condition, the kneecap (patella) may be left intact or its underside may be resurfaced.

The surgeon then tries out the implant parts, testing them to make sure they’ll work with the ligaments and tendons and allow the knee to straighten and bend without wobbling. Then the implant is cemented or screwed into place.

After The Operation

After surgery, you wake up to find your leg in a splint or a continuous passive motion (CPM) device, which gently bends and straightens your operated knee. You may also have elastic stockings or compression devices on your legs to prevent blood clots. Within 24 hours, your physical therapist will help you get out of bed and to a nearby chair, using crutches or a walker.

You may be in the hospital for five or six days, working daily with your physical therapist. You’ll learn how to protect your new joint while you bathe, dress, and get into and out of a car. Before going home, you may need to demonstrate that you can straighten your knee and bend it 90°, get into and out of bed, walk with crutches or a walker, and perform certain necessary tasks at home.

Realistic Expectations

How long you’ll need to use crutches depends in part on whether the implant is a cemented or a cementless model. You can place your weight on a cemented model as soon as it’s comfortable. But a screwed-in implant isn’t secure enough to bear your full weight until bone grows into it, which is about six weeks’ time.

With a new knee, you may have dramatic pain relief, and with proper rehabilitation treatments, you’ll probably be able to engage in normal activities for your age. But a knee replacement won’t allow you to do more than you could before surgery, and you may need to give up certain activities you once enjoyed.

An artificial knee won’t hold up to the twisting, jumping, or repeated jarring of athletic activity such as running or jogging, soccer, basketball, volleyball, contact sports, singles tennis, or high-impact aerobics. You may be able to return to golfing, bowling, recreational walking and biking, swimming, scuba diving, or ballroom dancing.

A good outcome following a knee replacement requires hard work on your part. You’ll need to stick with your physical therapy program and diligently perform your home exercises. You may be able to go back to your job and resume certain other activities after a couple of months. But it may take up to a year before your new knee really feels like a real part of your old self!

Reported by: Sol Jose Vanzi

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