Patellofemoral pain syndrome (PFPS) is 1 of the most common types of knee pain, particularly among athletes, active teenagers, older adults, and people who do physical labor. Patellofemoral pain affects more women than men and accounts for 20%-25% of all reported knee pain.
What is Patellofemoral Pain?
Patellofemoral pain syndrome refers to pain at the front of the knee, in and around the kneecap. (The kneecap, or patella, is the triangle-shaped bone at the front of the knee joint. The pain usually is accompanied by tenderness along the edges of the patella.
Current research indicates that PFPS is an “overuse syndrome,” which means that it may result from repetitive or excessive use of the knee. Other contributing causes may include:
- Weakness, tightness, or stiffness in the muscles around the knee
- An abnormality in the way the lower leg lines up with the hip, knee, and foot
These conditions can interfere with the ability of the patella to glide smoothly on the femur (the bone that connects the knee to the thigh) during movement. The friction between the under-surface of the patella and the femur causes the pain and irritation commonly seen in PFPS.
PFPS often occurs in people who are physically active or who have suddenly increased their level of activity, especially when that activity involves repeated knee motion, running, stair climbing, squatting, or repeated carrying of heavy loads. If you are older, you might have age-related changes that cause the cartilage on the under-surface of the patella to wear out. The result is pain and difficulty completing even the simplest daily tasks without pain.
Usually, patellofemoral pain is worse when you walk up or down hills or stairs and on uneven surfaces. This pain tends to increase with activity and improve with rest. You also may:
- Feel pain after sitting for long periods of time with the knee bent
- Occasionally hear or feel a “cracking” or “popping” when you bend or straighten your knee
How Is It Diagnosed?
Your physical therapist will review your health history, perform a thorough examination, and conduct a series of tests to evaluate the knee. Physical therapists use tests such as the patellar apprehension test, the Q-angle test, the patella alta test, and Clarke’s sign (patellar grind test) to determine whether the patellofemoral joint is the source of pain.
In addition, your therapist may observe the alignment of your feet, analyze your walking and running patterns, and test the strength of your hip and thigh muscles to find out whether there is a weakness or imbalance that might be contributing to your pain. Finally, your therapist will check the flexibility of the muscles in your leg, paying close attention to those that attach at the knee.
Generally, x-rays are not needed to diagnose PFPS.
How Can a Physical Therapist Help?
After a comprehensive evaluation, your therapist will analyze the findings and prescribe an exercise and rehabilitation program just for you. Your program may include:
- Strengthening exercises targeted at the hip (specifically the abductor and rotator muscles of the buttock and thigh), the knee (specifically the quadriceps femoris muscle, which is located on the front of your thigh and straightens your knee), and the ankle
- Stretching exercises for the muscles of the hip, knee, and ankle
- Taping of the patella to reduce pain and retrain muscles to work efficiently
- Exercises for improving your performance of activities that have become difficult for you
If the alignment and position of your foot and arch appear to be contributing to your knee pain, your physical therapist may fit you with a special shoe insert called an orthosis. The orthosis can decrease the stress to your knee caused by excessive rotation or impact during walking and running.
If your pain is persistent, your physical therapist may:
- Have you try a lightweight brace
- Use pain-reducing treatments such as electrical stimulation
- Recommend that you apply ice or heat at home for relief
Your physical therapist will work with you to help you stay active and maintain your fitness level. You may need to modify your activity level or change your training activities until you recover; your therapist will show you how to do activities and exercises that will not increase your pain. Most important, your therapist can make recommendations to help prevent PFPS from returning.
Can this Injury or Condition be Prevented?
PFPS is much easier to treat if it is caught early. Report the first signs of knee pain to your physical therapist. Early treatment by a physical therapist may help stop the underlying problem before it gets worse. Your physical therapist also can help you adjust your daily activities and teach you exercises to do at home to strengthen your muscles and bones and help prevent PFPS from recurring.
Real Life Experiences
Amelia is a 25-year-old training for her first marathon. She began by training on very flat ground and has just moved to a hilly area. Over the past 4 weeks, she has noticed some pain in the front of her knee. At first, she tried to continue her training, but now she stops running after 2 or 3 miles because of knee pain.
Amelia’s physical therapist completes a comprehensive evaluation, including a screening for other possible conditions that might be causing her pain. He uses special tests to measure her strength and finds that she has weak hip abductor and quadriceps muscles and tenderness around the patella. The therapist also determines that Amelia has flat feet and is not wearing supportive running shoes.
The therapist uses special tape on the front of Amelia’s knee to help reduce her pain, instructs Amelia in the use of ice to decrease her symptoms, and designs a specific home program of exercises for Amelia to do regularly between sessions. He provides information about proper shoe choices for her foot and body type and advises her to purchase shoes that will give her feet the right type of support. He also recommends that she try deep-water running or swimming for a week instead of her regular training program until her condition improves.
After the first week, Amelia notices about a 25% decrease in her pain and an increased ability to go up and down stairs without pain. Her physical therapist progresses her home program to include more challenging exercises and gives her the go-ahead to race-walk. She applies ice only when she has pain.
After 2 weeks, Amelia reports about a 60% reduction in her pain. Her physical therapist continues to increase the intensity of her exercises, and she starts to run again—but only on flat surfaces.
After 3 weeks of therapy, Amelia feels only slight twinges of pain and has resumed her prior level of training. Her therapist recommends continuation of her stretching and strengthening exercises and discharges her from formal care. Amelia completes her first marathon 10 weeks later with no difficulty.
This story was based on a real-life case. Your case may be different. Your physical therapist will tailor a treatment program to your specific case.
What Kind of Physical Therapist Do I Need?
All physical therapists are prepared through education and experience to treat a variety of conditions or injuries. You may want to consider:
- A physical therapist who is experienced in treating people with orthopedic, or musculoskeletal, problems.
- A physical therapist who is a board-certified clinical specialist or who has completed a residency or fellowship in orthopedic physical therapy has advanced knowledge, experience, and skills that may apply to your condition.
You can find physical therapists who have these and other credentials by using Find a PT, the online tool built by the American Physical Therapy Association to help you search for physical therapists with specific clinical expertise in your geographic area.
General tips when you’re looking for a physical therapist:
- Get recommendations from family and friends or from other health care providers.
- When you contact a physical therapy clinic for an appointment, ask about the physical therapist’s experience in helping people with patellofemoral pain syndrome.
During your first visit with the physical therapist, be prepared to describe your symptoms in as much detail as possible, and say what makes your symptoms worse.
The following articles provide some of the best scientific evidence related to physical therapy treatment of patellofemoral pain syndrome. The articles report recent research and give an overview of the standards of practice both in the United States and internationally. The article titles are linked either to a PubMed* abstract of the article or to free access of the full article, so that you can read it or print out a copy to bring with you to your health care provider.
Bizzini M, Childs JD, Piva SR, Delitto A. Systematic review of the quality of randomized controlled trials for patellofemoral pain syndrome. J Ortho Sports Phys Ther. 2003;33:4–20. Article Summary on PubMed.
Crossley K, Bennell K, Green S, et al. Physical therapy for patellofemoral pain: a randomized, double-blinded, placebo-controlled trial. Am J Sports Med. 2002;30:857–865. Article Summary on PubMed.
Davis IS, Powers CM. Patellofemoral pain syndrome: proximal, distal and local factors, an international retreat, April 30-May 2, 2009, Fells Point, Baltimore, MD. J Orthop Sports Phys Ther. 2010;40:A1–A16. Article Summary on PubMed.
Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75:194–202. Free Article.
Fukuda TY, Rossetto FM, Magalhaes E, et al. Short-term effects of hip abductors and lateral rotators strengthening in females with patellofemoral pain syndrome: a randomized controlled clinical trial. J Orthop Sports Phys Ther. 2010;40:736–742. Article Summary on PubMed.
Knee pain—strengthen my hips: but it’s my knees that hurt! J Orthop Sports Phys Ther. 2011;41:571. Article Summary on PubMed.
Powers CM, Ward SR, Chan LD, et al. The effect of bracing on patella alignment and patellofemoral joint contact area. Med Sci Sports Exerc. 2004;36:1226-1232. Article Summary on PubMed.
Acknowledgement: Christopher Bise, PT, MS, DPT
* PubMed is a free online resource developed by the National Center for Biotechnology Information (NCBI). PubMed contains millions of citations to biomedical literature, including citations in the National Library of Medicine’s MEDLINE database.