Playing team sports, jogging, or doing other high impact activities that repeatedly pound, twist, and turn the knees can stress aging joints. Highly active, middle-aged patients may develop painful knees as a result of osteoarthritis (OA). This painful condition happens when the cartilage lining on the ends of bones gradually wears away.

It can affect one or both knees.

• Symptoms: You may experience pain when standing or going up and down stairs. The knee may buckle and give way, lock in place, or become stiff and swollen.

Left, normal joint space between the femur and tibia. Right, decreased joint space due to damage from osteoarthritis.
• Patients: Most people with osteoarthritis of the knee are over age 55 and/or obese and/or have a family history of osteoarthritis. Younger, highly active people may also develop osteoarthritis if their knee suffered a significant injury.
• Diagnosis: See your doctor for diagnosis and treatment. The doctor will consider your comprehensive medical history, perform a physical examination and possibly order tests and/or imaging studies before recommending a course of treatment.

Increasingly, baby boomers with osteoarthritis of the knee are asking for total knee replacement surgery. But first they should try making changes to their lifestyles. Mayo Clinic orthopaedic surgeon Arlen D. Hanssen, MD presented a briefing on "Our Aging Population" at the 2002 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS). He said many highly active patients in their 40s and 50s feel inspired by advertising and news reports about the success of knee replacement surgeries. But often they refuse to change their lifestyles to extend the life of their natural knees.

"They come in and say, 'Fix me','" Dr. Hanssen explained, and they hope for a complete end to their symptoms without making any changes in their activities. In reality, doctors use a complex medical process to determine whether total knee replacement is appropriate for a patient. They consider age, activity demands, and other factors. Long-term results of joint replacement are less certain in younger patients.

For middle-aged people, the earlier a doctor diagnoses osteoarthritis of the knee, the more likely conservative treatment may help. If osteoarthritis of the knee is in its early stages, your doctor may recommend low impact activities and other non-operative treatments that can delay or eliminate the need for surgery. In some cases, activity modification may be the only treatment a middle-aged patient needs. "In other cases when surgery is eventually needed, the patient still has to modify activities first to preserve the replacement joint," Hanssen advises.

Moderate physical activity lessens joint pain and improves flexibility and function. Baby boomer patients with osteoarthritis of the knee should continue exercising, but change the forms of their activities:

• Stop doing high-impact activities that twist and turn the joints. This includes running, tennis, racquetball, basketball, baseball, etc.
• Start doing smooth, low-impact activities that are easier on the joints. Recommended activities include stretching, swimming, water aerobics, cycling, walking on a treadmill or outside, playing golf, etc.

Other options that may extend the life of your natural knee include medications, steroid injections, physical therapy, and mechanical aids.

• Medications: The doctor may prescribe nonsteroidal anti-inflammatory medications to help reduce inflammation. Certain dietary supplements such as Glucosamine and Chondroitin may also be helpful. (Note: The U.S. Food and Drug Administration does not test dietary supplements. These compounds may cause negative interactions with other medications or excessive bleeding during surgery. Always consult your doctor before taking dietary supplements.)
• Injections: The doctor may inject the knee joint with strong anti-inflammatory medications, called corticosteroids. This can relieve pain and swelling for awhile. Viscosupplementation or injection of hyaluronic acid preparations may also help relieve the symptoms of an arthritic knee.
• Physical therapy: The doctor may give you a balanced fitness program including physical/occupational therapy to improve joint flexibility, increase range of motion, strengthen muscle, bone and cartilage tissues and reduce pain. It may also help to ice the affected joint for short periods, several times a day.
• Mechanical aids: You may need supportive or assistive devices such as an elastic bandage, splint, brace, cane, crutches, or walker.