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Knee Pain

Chondromalacia Patella

Most joints in your body are cushioned with a type of tissue called articular cartilage. This tough, rubbery tissue covers the ends of bones inside a joint. As the joint moves, the cartilage helps to cushion the bones and allows them to glide smoothly against one another.

Sometimes, the cartilage inside a joint softens and breaks down. This condition is called chondromalacia. The cartilage loses its ability to protect the ends of the bones as the joint moves. The ends of the bones can rub together, causing pain.

Chondromalacia can affect any joint, but the most common location is the underside of the kneecap (also called the patella); when affecting the knee, this condition is called chondromalcia patella. It usually begins as a small area of softened cartilage behind the kneecap that can be painful. Eventually, more of the cartilage softens, and the softened cartilage can crack or shred into a mass of fibers. In severe cases, the damaged cartilage can wear away completely, down to the undersurface of the kneecap. If this happens, the exposed kneecap's bony surface can grind painfully against other knee bones. Also, bits of cartilage can float inside the joint, further irritating the cells that line the joint. In response, these cells may produce extra fluid inside the joint (called a joint effusion).


Typically, there is a layer of cartilage behind the patella. When the knee bends, the patella glides over the knee joint, and this layer of cartilage protects the knee joint from damage while supporting its full range of movement.

Several tendons and ligaments hold the kneecap in place. If any of these structures fail to function as they should, it can cause the kneecap to rub on the femur below. This abnormal movement can cause the cartilage under the patella to deteriorateTrusted Source.

This atypical movement can be the result of many different conditions or circumstances. Some of these include:

  • Poor structural alignment: For example, a person’s knee may form differently from a hereditary health condition.

  • Muscle weakness: If a person has a stronger quadriceps on one leg than the other, this can place more strain on one side. Weak abdominal muscles can cause structural irregularity, affectingTrusted Source how the knee joint functions.

  • Overuse in sports: Repetitive stress on the joint, such as from running or skiing, can cause chondromalacia patellar. This is why some people call the condition “runner’s knee.”

  • Traumatic injury: Patella injury, knee surgery, injury of the tendons or ligaments around the knee joint, or a bone fracture can cause the knee joint to move abnormally.


Chondromalacia most often causes a person to experience dull, aching pains in the front of the knee.

A person may experience crunching, pain, and stiffness in their knee joints during certain movements. These can include:

  • squatting

  • kneeling

  • sitting for extended periods

  • climbing or descending stairs

In some rare instances, a person may have effusion of the knee. This is when fluid gathers at the knee joint, causing swelling.

If a person experiences pain in their knee for longer than a few weeks, they should seek advice from their doctor. Chronic knee pain is pain that lasts for 8–12 weeks or longer.


Your doctor will look for areas of swelling or tenderness in your knee. They may also look at how your kneecap aligns with your thigh bone. A misalignment can be an indicator of chondromalacia patellae. Your doctor may also apply resistive pressure to your extended kneecap to determine the tenderness and severity.

Afterward, your doctor may request any of the following tests to aid in diagnosis and grading:

  • X-rays to show bone damage or signs of misalignment or arthritis

  • magnetic resonance imaging (MRI) to view cartilage wear and tear

  • arthroscopic exam, a minimally invasive procedure to visualize the inside of the knee that involves inserting an endoscope and camera into the knee joint

Non-surgical treatments

The goal of treatment is to reduce the pressure on your kneecap and joint. Resting, stabilizing, and icing the joint may be the first line of treatment. The cartilage damage resulting in runner’s knee can often repair itself with rest.

Your doctor may prescribe several weeks of anti-inflammatory medication, such as ibuprofen, to reduce inflammation around the joint. If swelling, tenderness, and pain persist, the following treatment options may be explored.

Physical therapy focusing on strengthening the quadriceps, hamstrings, adductors, and abductors can help improve your muscle strength and balance. Muscle balance will help prevent knee misalignment.

Typically recommended are non-weight-bearing exercises, such as swimming or riding a stationary bike. Additionally, isometric exercises that involve tightening and releasing your muscles can help to maintain muscle mass.