Patellofemoral pain syndrome

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.

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.

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.

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.

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.

Your healthcare professional might ask about your history of knee issues and discuss what activities you do. Diagnosis also relies on a physical exam. During the exam, your healthcare professional may press on your knee, move your leg into a variety of positions, and watch how you walk, squat or climb stairs.

Sometimes imaging tests can help find the cause of knee pain. Tests might include:

• X-rays. X-ray images show bones well. X-rays aren't as good for viewing soft tissues.
• MRI. Using radio waves and a strong magnetic field, MRIs show detailed images of bones and soft tissues, such as the knee ligaments and cartilage. But MRI scans cost much more than X-rays, CT scans or ultrasounds.
• Ultrasound. This test uses soundwaves to show images of muscles and tendons.

Treatment of patellofemoral pain often begins with simple measures. Rest the knee as much as possible. Try not to do things that increase the pain, such as climbing stairs repetitively, kneeling or squatting.

Medicines

If needed, take pain relievers you can get without a prescription. These include acetaminophen (Tylenol, others), ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve). Don't take them for more than 2 to 3 weeks.

Therapy

A physical therapist might suggest:

• Rehabilitation exercises. Certain exercises strengthen the muscles that support the knees and keep the leg in line. Keeping the knee from moving inward while squatting is a main goal.
• Better movement training. Physical therapists now work on how you move, not just strength. This includes learning better landing and squatting techniques, adjusting running form, and improving balance and coordination.
• Supportive braces. Knee braces or arch supports may help reduce pain.
• Taping. Your physical therapist may show you how to tape your knee to reduce pain and make it easier to exercise.
• Icing. Icing your knee after exercise might help with pain and swelling.
• Orthotics. Custom-made or ready-made shoe inserts might help take stress off the knee.
• Knee-friendly sports. During recovery, it might help to stick to sports that are easier on the knees, such as bicycling or swimming.

Surgery and other procedures

If simple treatments don't relieve pain, your healthcare professional might suggest:

• Targeted injections. Corticosteroid injections may help give short-term relief for pain. Hyaluronic acid injections can help lubricate the joint and may help relieve pain for several months. Other injection types, including platelet-rich plasma, are still being studied and are used selectively for treatment of patellofemoral pain.
• Arthroscopy. During this procedure, a surgeon inserts a pencil-thin device into the knee through a tiny cut in the skin. This device, called an arthroscope, has a camera lens and light. Tools to repair the knee can be inserted through other small cuts in the skin.
• Realignment. In more-severe cases, a surgeon may need to operate on the knee to fix the angle of the kneecap or relieve pressure on the cartilage.

You might start by seeing your primary care team. Or you might be referred to a physical medicine and rehabilitation specialist, also known as a physiatrist, a physical therapist, an orthopedic surgeon or a sports medicine specialist.

Here's information to help you get ready for your appointment.

What you can do

Before your appointment, make a list of the following:

• Your symptoms and when they began.
• Key personal information, including whether you've ever injured your knee or had knee surgery and what type of exercise or sports you take part in.
• All medicines, vitamins or supplements you take, including doses.
• Questions to ask your healthcare team.

Take a family member or friend along, if possible, to help you remember the information you're given. Also, if you've had X-rays or other imaging tests of your knees, try to bring copies of them to your appointment.

For patellofemoral pain syndrome, questions to ask your healthcare team include:

• What's likely causing my knee pain?
• What are other possible causes?
• What tests do I need?
• Is my condition likely temporary or long-lasting?
• What's the best course of action?
• Do I need to restrict my activities?
• Should I see a specialist?
• Are there brochures or other printed materials I can have? What websites do you recommend?

Ask any other questions you have.

What to expect from your doctor

Be prepared to answer questions, such as:

• How would you describe your knee pain?
• Where exactly does it hurt?
• What activities improve or worsen your symptoms?
• Have you recently started exercising or exercising more?
• What home treatments have you tried? Did they help?