I see 2 types of patients in my orthopedic practice: people that are inactive and “rust out” and people that are active and “wear out.” Rust out issues are much more difficult to treat. Our joints are like a barn door, if it is rarely opened, it will rust shut; articular cartilage must be lubricated. Motion produces a cascade sequence that lubricates the joint. If joints aren’t lubricated arthritis will set in and permanently limit future motion. No motion by choice leads to no-motion by a bad choice.
Let’s look at the knee. The biggest culprit for premature aging is too much sitting. When the knee bends to 90 degrees of flexion, the contact pressure between the cartilage on the kneecap and the cartilage on the femur increases to 2-3 times your body weight. Cartilage is initially like fresh coconut: thick, rubbery and smooth. When deterioration occurs the cartilage becomes soft like a wet sponge, starts to fragment and eventually is worn down like treads on a bald car tire.
Preventative treatment aimed at delaying this aging process includes extending your knee while sitting, adjusting the height of your chair to determine the most comfortable amount of flexion for your knee, and taking multiple breaks from the sitting position.
By far, the best exercise for the knee is a stationary, road or mountain bike. This exercise puts less weight across the joint surfaces and the repetitive cycling motion lubricates the cartilage. I recommend for people with sedentary jobs to ride at 20 minutes on the bike per day. The spinning motion that occurs with pedaling is the equivalent of squirting a can of oil in your joints. The process lubricates and nourishes the cartilage that you already have and stimulates the repair of cartilage that has been previously damaged.
Riding 20 minutes per day will lead to knees that feel 20 years younger. Prevent the rust and delay the wear, now that’s a great ride!