Chondromalacia patella occurs when the cartilage of a person’s kneecap softens. It is common in athletes of high impact sports or those who have arthritis in their knees.

Chondromalacia patella is when the cartilage of the underside of the kneecap begins to break down.

This article explains what chondromalacia patella is, the causes of the condition, and how a doctor can treat it.

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Chondromalacia patella can develop gradually, when the cartilage on the underside of a person’s knee wears away, causing grinding and rubbing of the kneecap over the knee joint during movement. This can result in inflammation and pain.

It can also result from a traumatic injury that causes direct injury to the cartilage, such as a knee fracture.

Doctors refer to this pain as patellofemoral pain syndrome.

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.

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 deteriorate.

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, affecting 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.

Some factors that increase the risk of developing chondromalacia patella include:

  • Age: Young adults and athletes that participate in high impact sports are the most at risk of developing the condition. However, as a person ages, the quality of their cartilage deteriorates, which can cause this condition to develop in older people too.
  • Sex: Biological sex is a possible risk factor. A 2022 study found that chondromalacia patellar may occur more frequently in females. This may be because females have a larger Q angle, which measures the angle between the quadriceps muscles and the patella tendon.
  • Certain activities: High impact sports can cause stress on the knee joint. Manual work that involves repetitive strain on the knee joint can also increase a person’s risk.
  • Being overweight: People with overweight or obesity are at an increased risk of developing this condition.

Diagnosis involves a physical examination to check for signs of swelling.

A medical professional will observe a person’s knee to check the alignment of the bones that form the knee joint. Misalignment can be an indication that a person has chondromalacia patella.

By applying pressure to different areas of the knee, a medical professional will determine the degree of swelling and soreness in the joint.

The medical professional will flex and extend the knee to assess patellar alignment and pain.

Several types of imaging tests can help a doctor diagnose the condition and determine its severity:

  • CT scans: CT scans use X-rays to provide further information on the alignment of the joint, as well as any other abnormalities. However, a plain X-ray will not be able to detect chondromalacia in the early stages.
  • MRI scans: MRI scans can show the degree of cartilage deterioration in the knee joint.
  • Arthroscopic examination: This is a minimally invasive procedure that allows a surgeon to visualize the interior of the knee joint.

Healthcare professionals use a grading system to determine the severity of a person’s condition:

  • Grade 1: softening of cartilage in the knee area
  • Grade 2: softening of the cartilage but with abnormal textural characteristics
  • Grade 3: active deterioration of the tissue
  • Grade 4: bone exposure with bone-to-bone contact

Treatment for this condition should aim to reduce the pressure on the knee joint. Damage to cartilage from “runner’s knee” can often self-repair with ice and rest.

A doctor may prescribe nonsteroidal anti-inflammatory drugs (NSAIDs) to help this process. If a person’s condition is severe, they may require further treatment.


If misalignment is the problem, lateral release surgery to release the lateral retinaculum tendon can loosen tissues and realign the patella. A cartilage graft may also be suitable.

Other surgical options include:

  • Arthroscopic or open lateral retinacular release: This involves surgically correcting a tilt in the kneecap. Surgeons can perform it as an open or keyhole surgery.
  • Patellar realignment: Surgeons will realign the kneecap if it has moved out of position.
  • Patellectomy: This procedure can be partial or total, meaning a surgeon may remove all or part of the kneecap. They may replace it with a prosthetic kneecap. Surgeons may only recommend this procedure for people with well-functioning quadriceps and those who can exercise regularly after the surgery.

Physical therapy

Strengthening the quadriceps, hamstrings, adductors, and abductors through physical therapy helps remove pressure and stress on the knee joint.

It can also help prevent future knee misalignment by balancing muscular strength. A physical therapist may recommend isometric exercises that involve contracting muscles without moving the joints.

This section answers some frequently asked questions about chondromalacia.

What happens if chondromalacia goes untreated?

The longer the condition goes without treatment, the more exposure the bone below receives.

This will further the severity of the condition and make it more difficult to treat successfully.

Is chondromalacia the same as arthritis?

Chondromalacia can be an early warning sign of arthritis in the knee joint. However, it is not a type of arthritis. If left without treatment, it may develop into osteoarthritis.

Chondromalacia patella is the deterioration of cartilage underneath the patella. It may be more likely to occur in younger adults and athletes.

Unlike arthritis, this damage can heal. Rest and physical therapy can relieve symptoms and encourage healing. In severe instances, surgery may be necessary to reduce stress on the knee joint.