Exercise is the secret to successful knee replacement surgery.

Knee replacement surgeries are becoming much more common, especially among people between the ages of 45 and 64. Researchers at the Hospital for Special Surgery in New York found that excess body weight, which causes a lot of wear and tear on knee joints, accounts for 95 percent of the growing demand for such surgeries, which more than tripled between 1993 and 2009.

Although weight loss is definitely good for the knees, trying to do it with high-impact exercise can be dangerous. “When you’re jogging or running, your impact is about six times your body weight on your knee joint,” says Jennifer Beal, a doctor of physical therapy (DPT) in West Palm Beach, Fla., and an international consultant in joint replacement.

For anyone who is overweight, Beal recommends gentle cardio, avoiding movement win which your heels hit the ground, sending a shockwave to the knees. A stationary bike is gentlest, followed by an elliptical trainer. As you lose weight, progress to a treadmill, and finally to walking outdoors.

If you opt for knee surgery, some simple exercises can make the difference between full or partial recovery. And if you don’t choose surgery, the same exercises can help to improve function and reduce pain in arthritic knees.

Where to Start

Before surgery, Beal recommends avoiding squatting or any other exercise that stresses the knee joint. To increase circulation to the knee and enhance flexibility, regularly ride a stationary bike with low resistance, making sure that it’s adjusted for your leg length and body size. If you have back pain or find it uncomfortable, use a recumbent bike on which you sit farther back with your legs pedaling in front of you.

In addition, you can do the following exercises that are recommended after surgery, as these will speed recovery and help you control and strengthen all the muscles that support and move the knee.

Post Surgery

You will use a walker and/or a cane. See a physical therapist to learn to do this correctly, and be patient. Using walking aids incorrectly, or walking unsupported too soon, says Beal, can lead to bad habits that leave you with a permanent limp.

To regain motion and strength, and reduce swelling, she recommends starting these exercises as soon as possible after (and before) surgery. Do each exercise
3 or 4 times daily.

Quad squeezes: Lie down or sit with your leg propped up straight in front. Squeeze your quad muscles, on the front of your thigh. Hold the squeeze for 5 seconds, release, and repeat for a total of 10 squeezes or until the muscle is fatigued.

Ankle circles: To work the calf muscle, circle your ankle 20 times in each direction. Or, write the letters of the alphabet with your toes.

Straight leg raises: Stand on your healthy leg and support yourself for balance. With your knee straight, raise your leg forward, back, and to the side, for a total of 10 in each direction, or as many as you can. For added resistance, put a resistance band around your ankles but make sure to keep your knees straight.

Heel slides: Lie down on your back with straight legs. Using your hamstrings on the back of your thighs, slide your heels toward your butt and back down to straight legs. Do this a total of 10 times.

Knee surgery after an injury requires customized exercises from a physical therapist. For more tips, visit the Medical Library in the Patient Center at bealpt.com.

Top Joint Health Supplements

In studies, these supplements have been shown to cushion joints and quell inflammation in osteoarthritis in the knee.

Turmeric (Curcuma longa): A medicinal herb and the spice that gives curry its telltale yellow color, turmeric contains curcumin, a natural substance that calms inflammation and relieves pain. A 4,000-year-old remedy, its efficacy is also supported by research. One study in Thailand found that 2 grams daily of a curcumin extract was as effective as 800 mg of ibuprofen. Extracts vary, so follow product directions.

Glucosamine, chondroitin, and MSM: Available as individual supplements or in combination formulas, glucosamine and chondroitin help restore the structure of joints, MSM reduces inflammation and pain, and together they work synergistically. A common twice-daily dose is 750 mg of glucosamine and 600 mg of chondroitin. MSM dosages vary.