Patellofemoral pain syndrome

Overview

Patellofemoral (puh-tel-o-FEM-uh-rul) pain syndrome is pain felt in the front of the knee, around or behind the kneecap. The kneecap also is known as the patella. Patellofemoral pain syndrome is sometimes called runner's knee.

The condition is more common in people who run and who play sports that involve running and jumping. The knee pain often increases when running, walking up or down stairs, sitting for long periods, or squatting. Simple treatments, such as rest and ice, often help. But sometimes patellofemoral pain needs physical therapy.

Symptoms

The kneecap helps protect your knee joint and plays a role in how the knee bends and straightens. Patellofemoral pain syndrome happens when there is pain in the soft tissues and bone around the kneecap. Sometimes another condition called chondromalacia patellae also can cause patellofemoral pain. Chondromalacia patellae is damage to the cartilage under the kneecap.

Patellofemoral pain syndrome symptoms often start slowly. The condition can affect one or both knees. Common symptoms include:

• Dull pain or ache in the front of the knee.
• Pain when going up or down stairs.
• Pain with running, jumping, squatting or kneeling.
• Pain after sitting for a long time with knees bent.
• Popping or crackling feeling in the knee.

When to see your doctor

If the knee pain doesn't improve within a few days or it gets harder to move the knee, call your healthcare professional.

Causes

Patellofemoral pain syndrome usually happens when the kneecap does not move smoothly as the knee bends and straightens. Causes may include:

• Overuse. Running or jumping sports put repeated stress on the knee joint, which can cause irritation under the kneecap.
• Sudden increase in activity. Longer workouts or more frequent exercise can cause the condition.
• Muscle imbalances or weakness. Patellofemoral pain can happen when the muscles around the hip and knee don't keep the kneecap in line. Moving the knee inward during a squat has been linked to patellofemoral pain.
• Injury. Trauma to the kneecap, such as when the kneecap slips out of place or damages the cartilage, has been linked to patellofemoral pain syndrome.
• Surgery. Knee surgery also can increase the risk of patellofemoral pain. This is especially true of reconstruction of the anterior cruciate ligament using your own patellar tendon as a graft.

Risk factors

Factors that can increase your risk of developing patellofemoral pain include:

• Age. Patellofemoral pain syndrome typically affects teens and young adults. Arthritis is more often to blame for knee issues in older people.
• Sex assigned at birth. Females are twice as likely to develop patellofemoral pain. This may be because females have wider pelvises. A wider pelvis increases the angle at which the bones in the knee joint meet.
• Certain sports. Sports that involve running and jumping can put extra stress on the knees. This is especially true when adding more training.

Prevention

Sometimes knee pain just happens. But certain steps may help prevent the pain.

• Build strength. Strong leg and hip muscles help keep the knee balanced during activity. Avoid deep squatting during weight training.
• Move safely. Ask a physical therapist about exercises to help you jump, run and turn correctly. It's especially important to strengthen your outer hip and core muscles. This likely will help keep your knee from caving inward when you squat, land from a jump or step down from a step.
• Lose excess pounds. If you're overweight, losing weight relieves stress on your knees, especially your kneecaps, during activities that require bending the knee, such as using the stairs.
• Warm up. Before running or doing other exercise, warm up with five minutes or so of light activity.
• Stretch. Promote flexibility with gentle stretching exercises.
• Build up slowly. Don't suddenly increase your workouts.
• Mind your shoes. Wear shoes that fit well and are designed for the activity.