Patellofemoral pain syndrome, also referred to as PFPS, is one of the most commonly reported knee problems, accounting for one in four knee complaints seen by orthopedists.
Signs and symptoms
- Pain in front of the knee, under and around the knee cap
- Increased pain when walking up stairs and especially with walking down stairs.
- Increased pain with kneeling and squatting
- Pain can worsen with activity and also occur with long bouts of inactivity
- Pain can occur in one or both knees
- Pain is usually described as “aching” but can also be “sharp” or “burning” pain
- A sensation that the knee may “give out” is often reported
- A grinding sensation can be felt or heard when the knee is extended
- Swelling around the knee can occur but is rare
Patellofemoral pain syndrome is caused by a multitude of factors that affect the way the patella moves along the groove of the femur (trochlear groove) when the leg is bent or straightened. The patella normally moves up and down with a slight tilt without touching the other knee bones. In PFPS patients, the patella rubs against the femur causing pain.
A combination of factors can cause this abnormal tracking and include the following:
- Overuse/overload injury: Repeated weight bearing impact sports such as soccer and running can cause PFPS.
- Anatomical defect: Flat feet and high arches can cause misalignment of the knee joint.
- Weak quadriceps muscles: Quadriceps, the anterior thigh muscles, function to help hold the kneecap in place during movement. Weak thigh muscles can lead to abnormal tracking of the patella, causing it to rub against the femur, producing pain in the kneecap.
Anyone can develop patellofemoral pain at any point in their lives; however, there are certain risk factors that may predispose you to developing patellofemoral pain. These include the following:
- Starting a new physical activity
- Increasing the intensity of a physical activity too quickly
- Injury or trauma to the kneecap can lead to recurring episodes of instability
- Unusual alignment of the kneecap
- Weak or tight thigh muscles
- Flat feet, knock knees, or high arches
- Females are affected more than men as wider hips increase stress on the kneecap
- Commonly seen in young athletes
Although it may not always be possible to prevent patellofemoral pain syndrome, there are some measures you can take to decrease your risk.
- Appropriate warm-up prior to beginning an activity
- Alternate high impact activities with low impact activities
- Run on softer surfaces
- Gradually increase distance or intensity level
- Proper footwear for your activity is essential
- Strengthening your quadriceps to prevent abnormal tracking of the patella
- Stop the activity if symptoms of PFPS occur with a gradual return once symptoms improve.
Evaluating the source of patellofemoral pain is critical in determining your treatment options for relief of the pain. Knee pain should be evaluated by an orthopedist for proper diagnosis and treatment.
Your physician will perform the following:
- Medical History
- Physical Examination
Depending on what the history and exam reveal, your doctor may order medical tests to determine the cause of your knee pain and to rule out other conditions.
- Diagnostic Studies may include:
A form of electromagnetic radiation that is used to take pictures of bones
- CT Scan
This test creates 3D images from multiple X-rays and shows your physician structures not seen on regular Xx-ray.
Magnetic and radio waves are used to create a computer image of soft tissue such as nerves and ligaments.
Treatment Options: Acute
Treatment for patellofemoral pain will depend on the exact cause of the pain and whether the pain is acute or chronic.
Treatment guidelines for acute PFPS include:
Pain Medications:Over the counter NSAID’s (non-steroidal anti-inflammatory drugs) such as ibuprofen can help with the pain and any swelling.
Rest: Stay off the injured knee as much as possible and avoid activities that cause the pain as more damage could result from putting pressure on the injury. You can perform non-weight bearing activities such as swimming. Slow, gradual resumption of activities
Ice: Ice packs applied to the injury will help diminish swelling and pain. Ice should be applied over a towel to the affected area for 20 minutes every hour. Never place ice directly over the skin.
Treatment Options: Chronic
If your knee pain persists despite the above treatments, your doctor may suggest more intensive treatments. These may include the following:
PT can teach you the proper stretching and strengthening exercises appropriate for your condition. Weak or tight quadriceps (thigh muscles) is a common cause of PFPS, so focusing on this muscle group is a primary focus for treatment of PFPS. If the cause of your knee pain is a different muscle group, such as hamstrings, your therapist will individualize your exercises accordingly.
Bracing: Soft braces with cut outs over the patella may be suggested for support and alignment.
Taping: Your therapist may show you how to tape the knee to bring it into proper alignment.
Orthotics: Shoe inserts may be ordered when PFPS is caused by foot abnormalities, such as flat feet.
Treatment Options: Surgery
Although uncommon, surgical treatment is sometimes necessary to help relieve the pain if your PFPS persists and does not respond to conservative treatment. Your surgeon may recommend arthroscopy to evaluate your condition and repair or remove any fragmented cartilage.