Definition

Patellofemoral pain syndrome is painful rubbing of the kneecap against the thigh bone. This pain occurs during exercise or movement. It is most common during impact actions such as running.

The Kneecap

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Causes

Swelling in the tissue around the kneecap causes the pain. It is often the result of overuse and improper use of the legs.

Risk Factors

The following factors increase your chance of developing patellofemoral pain syndrome:

  • Poor alignment of the knee joint caused by:
    • Feet rolling outward during walking or running—can pull the kneecap out of line
    • Kneecap that sits too high or too low in the knee joint
    • Loose ligaments
  • Weak or tight thigh muscles leading to:
    • Difficulty holding the kneecap in the correct position
    • Kneecap rubbing against the thigh bone during movement
  • Overuse and overloading the knee joint from:
    • High-impact sports or activities, such as running that result in pounding on the feet
    • Knock knees
    • Flat feet
    • High arches
    • Hip dysfunction
    • Outward turn (external rotation) of the lower leg
  • Trauma, such as a car accident where the kneecap hits the dashboard

Symptoms

The first symptom is pain around or under the kneecap. The pain may first appear during high-impact activities. Over time, the pain may appear with squatting, kneeling, or long periods of sitting. Pain is often increased by going down stairs or down hills.

Other symptoms may include:

  • Swelling of the knee
  • Popping or grinding sounds in the knee joint during activity
  • A snapping sensation in the knee

Diagnosis

Your doctor will ask you about your symptoms and health history. You will also have a physical exam. The diagnosis is often made based on the exam and your symptoms.

The doctor may also suggest images of your knee. These tests may help to rule out other problems. Your doctor may refer you to a specialist.

Treatment

The first step is to rest the knee. Look for low impact exercise options. For example, choose swimming instead of running. Your doctor may suggest that you apply ice to the kneecap after activity.

Long-term treatment may include one or more of the following:

A physical therapist will look for issues that may cause the pain. The findings will help to create a treatment plan. Part of the plan may include an exercise program. Increasing the strength of the muscles around the knee can help.

Over-the-counter medicine can help to manage pain.

Knee braces or knee sleeves may help some people. They may help to hold the kneecap in place during activity. Some are designed to stop the patella from going too far to the side. You may need to try a couple to see which works best for you.

Special shoe inserts, called orthotics, may also be helpful. They work best if there are foot problems such as flat feet or excessive turning in during walking.

The goal of surgery is to better align the kneecap. It may be an option if other treatments did not help.

Prevention

It may not be possible to prevent this condition. However, the following may decrease your risk:

  • Warm-up before you start an exercise.
  • Vary the types of activities that you do. For example, rather than run every day, switch between running and swimming.
  • Use the right shoes for your sport.
  • Slowly increase the amount and intensity of activity over time.
  • Use proper form and technique for any sport.
  • Take care of injuries right away. This includes getting first aid. Rest the injury until it is healed before starting again.
  • If you have knee or joint pain during activity, call your doctor.