Your knees are the largest joints in your body for a reason—you need them for practically everything you do. That’s probably why knee pain is common among people of all ages.
Lots of things can make your knees ache, and often depend on your age and how much you exercise. Read on for the most common culprits.
Feels like: Pain below the knee or across the front of the kneecap
Might be: Tendinitis
Sad, but true: sometimes, an active lifestyle can backfire if you fail to safeguard your knees. Cyclists, runners, and people who participate in jumping sports (tennis, basketball) are prone to patellar tendinitis, which usually causes pain across or just below the front of the kneecap. This overuse injury causes inflammation in the patellar tendon, which connects the quad muscle to the shin bone. “If the body is not trained appropriately, the load you’re putting on it will be too much too soon, and you’re going to get these overuse injuries,” Kaufman says.
Feels like: Your knee is tender, swollen, and is warm to the touch
Might be: Bursitis
Bursae are small, fluid-filled sacs that surround the knee joint. They provide double-duty support, cushioning pressure points between the bones in the knees and lubricating the joint, which reduces friction when you move. When the bursae become inflamed, they swell up, increasing friction between nearby tissue, and causing pain.
Feels like: Knee pain when bending accompanied by popping, swelling, stiffness, and pain
Might be: Torn meniscus
One of the most common knee injuries, a torn meniscus involves one (or both) of the C-shaped cartilaginous cushions that are on either side of the knee. In young people, it’s most often caused by some sort of trauma or overly aggressive pivoting of the knee—such as in athletes playing basketball or tennis.
As we get older, the causes of a torn meniscus tend to transition toward normal wear-and-tear degeneration.
Feels like: Stiff, tender knees that crack and swell
Might be: Arthritis
Osteoarthritis is the wear-and-tear type of arthritis, and it often strikes the knees. The most common form of arthritis, it usually begins in your 30s, and is caused by the deterioration of the cushiony tissue in the knee. Arthritis symptoms include stiffness, swelling, poor range of motion, and catching or grinding of the joint.
Other types of arthritis can also affect the knees, including rheumatoid arthritis and gout.
Feels like: Pain on outside the knee that extends up to the hip
Might be: IT band syndrome
Its name might sound daunting, but IT band syndrome is actually super treatable. The iliotibial band is a long band of tissue that runs down the side of the hip and attaches to the side of the knee. Runners, cyclists, and anyone else who repeatedly bends and straightens the knee are most likely going to overuse the muscles attached to the IT band. “The tightness can cause rubbing of the band over the side of the knee, causing inflammation and pain,” Tanaka says.