Patellofemoral Pain Syndrome (PFPS)

Patellofemoral pain syndrome (PFPS) is pain under or around your kneecap (patella). Healthcare providers also sometimes call it runner’s knee.

Your patella is the bone at the front of your knee joint. It helps your quadriceps muscle move your leg, protects your knee and supports lots of important muscles, tendons and ligaments.

Patellofemoral is the medical term for the connection between your patella and your thigh bone (femur). Usually, your patella fits into a groove in your femur and slides smoothly along that space when you move your knee. If you have PFPS, something may affect how your patella moves. This can make it painful.

People usually develop patellofemoral pain syndrome over time. It can affect one knee or both of your knees at once. Visit a healthcare provider if you’re experiencing knee pain that doesn’t get better in a few weeks.

Symptoms of patellofemoral pain syndrome

Pain in the front of your knee is the most common PFPS symptom. You might also hear or feel cracking or popping in your knees.

The pain typically gets worse when you:

• Bend your knees to squat or climb stairs
• Stand up after sitting with your knees bent for a long time
• Change your playing or training surface
• Increase your activity level or training intensity
• Wear new or different shoes when you’re active

PFPS usually feels like a dull ache at the front of your knee. You might feel it on the sides near your kneecap. It can change to feeling sharp or stabbing when you’re running, jumping, squatting or on stairs. Pain is especially common when you’re going downhill or down stairs.

Patellofemoral pain syndrome causes

Some factors that may lead to PFPS include:

• Weak or tight muscles around your knee: If the muscles in your legs around your knee (especially your quad muscles) are weak, they might not be able to support your knee like they should. Similarly, your quads and other muscles can put too much tension on your knee if they’re not very flexible.
• Suddenly increasing your activity level: You might develop PFPS if you start a new sport or activity or increase how often you’re active. It can also happen if you ramp up your practice or training intensity.
• Poor jumping or running form: Jumping or running in a way that puts a lot of sudden pressure on your knees can lead to PFPS. Experts call this a hard strike pattern. It can also happen if you land from jumps with your knees collapsing in toward the center of your body.
• The natural shape of your knee: You might develop PFPS if your patella is naturally an unusual shape. Your kneecap may not fit into the groove in your thigh bone like it should. This can cause PFPS, even without extra stress or strain.

Risk factors

Anyone can develop PFPS, especially after increasing their activity levels. Some groups of people are more likely to experience it, including:

• Athletes who run, jump or squat a lot
• People who do physical work
• Females
• Teenagers
• Adults ages 20 to 40

Complications of this condition

Patellofemoral pain syndrome usually gets worse over time if it’s not diagnosed and treated. Untreated PFPS may also increase your injury risk. The pain can make you hold your body and move differently, even if you’re not thinking about it. This can put extra stress on joints like your hips and ankles. It can also make you use muscles in your legs, belly or back more than you normally would.

How doctors diagnose this condition

A healthcare provider will diagnose patellofemoral pain syndrome with a physical exam. They’ll examine your knees and ask about the pain or any other symptoms you’ve had. Tell your provider when you first noticed pain and if any activities make it worse.

Your provider might ask you to move or use your knees. They may bend and straighten your knee or have you walk, run, jump or squat. This will help them look at your movements. Tell your provider if any of these motions hurt or make the pain worse.

You might need a knee X-ray or MRI to take pictures of your knee joint and the tissue around it.

What are patellofemoral pain syndrome treatments?

Your healthcare provider will suggest PFPS treatments that relieve the pain and help you move comfortably, including:

• Physical therapy: Increasing your quad muscle strength and flexibility will support your knee better and help your patella move like it should.
• Activity modification: You may have to change how you train or work out. Or you might have to tweak your form for running, jumping or squatting. Your physical therapist can help you change your movement techniques.
• Over-the-counter pain relievers: Most people can manage pain with NSAIDs or acetaminophen. Don’t take these medications for more than 10 days in a row without talking to your provider.

When should I see my healthcare provider?

Visit a healthcare provider if you’re having knee pain that doesn’t get better on its own after a few weeks of rest and at-home treatments. Talk to your provider or physical therapist if you’ve started treatment for PFPS and the pain comes back or gets worse. Let them know if certain exercises or positions hurt.

What is the recovery time for patellofemoral pain syndrome?

Most people need a month or two to recover from runner’s knee. Your provider or physical therapist will give you a timeline based on your unique needs, strength and activity level.

Plan to modify or take a break from your usual activities while you’re managing PFPS. You should be able to resume your sport or workouts once the pain gets better.

Can I prevent patellofemoral pain syndrome?

Ramp up your activity level slowly — especially if you’re starting a new sport or workout regimen.

The best way to prevent PFPS (and any other type of knee pain) is to stay safe when you’re physically active. During sports or other physical activities:

• Wear the right protective equipment. Make sure your shoes are supportive and aren’t worn out from use.
• Don’t “play through the pain” if your knees hurt during or after physical activity.
• Give your body time to rest and recover after intense activity.
• Stretch and warm up (especially your quad muscles) before playing sports or working out.
• Cool down and stretch after physical activity.
• Strengthen muscles in your lower body to help support your knees and other joints.

You might not be able to prevent PFPS if your patella doesn’t naturally fit into its groove in your femur. Your physical therapist can help you find ways to support the natural differences in your joint.