It also known as chondromalacia patellae.
The knee consists of moving parts, including the thigh bone (femur), shin bone (tibia), and the kneecap (patella). As these parts move, cartilage cushions them and prevents them from being worn away by friction.
But if this cartilage gets worn or damaged, the knee loses some of this protective cushion, resulting in a painful condition known as chondromalacia.
What is chondromalacia?
The thigh bone, shin, and kneecap are the three main bones in the knee.
Chondromalacia may lead to pain when bending the knee or when the knee straightens right after bending it.
This is why the knees often hurt when a person is going up or down stairs. This deeper movement means that the kneecap is forced to slide up and down over the femur more than usual.
If the cartilage is worn down, or the kneecap isn't sliding in its groove, a person may feel pain as the knees bend and straighten, and the bones rub on rough cartilage. The pain may go away when walking, however, because the knees don't have to move as much.
Squatting, kneeling, or sitting with the knees bent greater than 90 degrees may also cause pain with this condition. These activities all involve deep bending of the knee.
Even a slight swelling of the cartilage can be enough to trigger pain during these activities. Some people may also notice a cracking or grinding sensation after exercise or heavy use of the legs and knees.
Many people are surprised to find that their cartilage is damaged because they've never directly injured their knees. However, chondromalacia can be caused by more than an injury or accident. The most common causes include:
- Excessive use of the knees with running, jumping, or any activity that requires heavy use of the knees. Chondromalacia is often called "runner's knee" for this reason. It occurs in people of any age and is common in young, active athletes.
- A kneecap that is out of alignment. If the kneecap isn't in the proper position, the cartilage won't be able to protect it from rubbing. Some people are born with a misalignment of the knee that can cause this issue.
- Weak muscles in the thighs or calves. The leg muscles help support the knee and keep it in place. If they're not strong enough, the knee may slip out of alignment. Even a slight misalignment can gradually wear down the cartilage and cause pain over time.
- A knee injury, such as from an accident, fall, or blow to the knee. This could throw the kneecap out of proper alignment or damage the cartilage, or both.
Another cause is muscles that are not balanced. Strong thigh muscles combined with weaker calf muscles can also push the kneecap out of place. Similarly, strong outer thigh muscles and weak inner thigh muscles can cause misalignment. In some cases, adolescents have a temporary muscle imbalance as their body grows. This normally corrects itself over time.
People who have knee pain or symptoms of chondromalacia should see their doctor. Early treatment can prevent further damage to the cartilage and alleviate pain.
Treatment for chondromalacia can prevent further damage to the joint and reduce knee pain.
Typically, noninvasive treatments for chondromalacia are successful. They include:
- Low-impact exercise. Walking and swimming are good options to strengthen the legs and keep the muscles strong without stressing the knee.
- Avoiding activities that cause pain. Many people must avoid stairs if climbing them causes pain. Instead, they should do exercises that are comfortable. This may help avoid further damage to the cartilage.
- If a muscle imbalance is found, certain exercises may help balance the muscles and put the kneecap back in alignment. If the outside of the muscle is stronger than the inside, for example, exercises to strengthen the weaker muscles may be recommended.
- Physical therapy. A physical therapist works with patients to perform special exercises and stretches.
- Medications. Ibuprofen or naproxen are often recommended to help relieve pain and inflammation in the cartilage.
- Working toward a healthy weight. Being overweight can be damaging to knee cartilage. Losing weight can relieve stress on the knee joint.
Surgery will only be needed if the pain is severe and other treatments haven't helped. During surgery, the surgeon may remove the rough surface of cartilage to reduce pain. They may also be able to release tight tendons and ligaments. This can help to align the kneecap.
If chondromalacia isn't treated, it can lead to patella-femoral arthritis. This occurs when the cartilage gets severely worn away by damage. Once the cartilage is lost, it cannot grow back. In severe cases, the bones may directly rub together. If this happens, the pain may be debilitating and may be felt while resting.
A healthy lifestyle combined with exercise is good for the knees and all the joints. But knee pain should never be ignored. Pain during certain activities may be a warning sign of chondromalacia or another condition.
Some people wear kneepads when gardening, scrubbing floors, or other activities. Shoes with proper support are also helpful for the knees. Keeping both feet in alignment can help the leg muscles remain balanced, and quality shoes can help absorb shock from walking and running.
People who have a diagnosis of chondromalacia can still lead healthy, active lives. Early treatment can help prevent further irritation or damage to the cartilage. With proper treatment, many people get relief from pain and can do many of their favorite activities again.