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Patellofemoral pain is most often caused by overuse of the knee. When developing your exercise or sports routine, be sure to make gradual increases in your activity level.

Patellofemoral pain, often called chondromalacia patella or runner's knee, is the development of pain and inflammation on the underside of the patella (knee cap). The most common cause of patellofemoral pain is overuse from activities such as running, jumping, squatting or, less commonly, walking or cycling.

Causes
The patella is a triangular shaped bone that glides over the end of the femur (thigh bone) as the knee straightens or bends. The upper edge of the patella is attached to the tendon of the large quadriceps muscle in the thigh. The lower edge of the patella is attached to the patellar tendon, which travels down to the tibia (shin bone). As the knee is bent and straightened, the sliding of the patella may cause roughening, inflammation, and pain at the underside of the patella and around the front of the knee. Certain conditions may cause the patella to slide somewhat unevenly over the end of the femur, putting additional pressure on the patella cartilage.

Symptoms
Patellofemoral pain is commonly felt behind the kneecap, at the front of the knee. It typically appears after running, jumping, squatting or other activities that cause repetitive bending of the knee. Sitting for long periods of time with the knee bent can also cause pain. Patellofemoral pain is commonly made worse by activities such as walking down stairs or hills.

Risk Factors
Factors that can contribute to patellofemoral pain are overuse of the knee or errors in training (such as adding miles too quickly to a running program). Muscle weakness and tightness can also contribute to patellofemoral pain. Patellofemoral pain can also be caused by slight variations in bone alignment and movement, such as knee caps that are not evenly centered over the end of the femur, a valgus (knock kneed) knee alignment and feet with arches that collapse during weight-bearing (over pronation).

Diagnosis
Your doctor can diagnose patellofemoral pain by examining the knee and learning more about the onset, location and nature of the pain. X-rays of the knee may also be taken to identify such factors as patellar alignment and to rule out other causes of pain such as arthritis.

Treatment
Initial treatment is directed at decreasing the inflammation under the patella.

Other helpful treatments include:

  • Rest . All activities that reproduce the pain should be restricted. This typically would involve activities such as running down hill or squatting. Talk with your doctor about a plan for gradually returning to full activity.
  • Ice . Ice packs may be used for about 20 minutes at a time, each hour to help alleviate pain and decrease swelling.
  • Bandage/Compression Wraps . Your doctor may recommend that you use a soft elastic wrap or bandage at the knee to help reduce swelling.
  • Elevation . If the knee is swollen, elevation should help ease pain and swelling.
  • Medication . Your doctor may prescribe an anti-inflammatory medication.
  • Knee Brace . Your doctor may prescribe a knee brace to help stabilize the joint.
  • Crutches . In severe cases, your doctor may advise you to use crutches to take pressure off the knee.
  • Physical Therapy . Your doctor or physical therapist may recommend a stretching and strengthening program for the muscles surrounding your knee to help reduce pain and to prevent recurrence of patellofemoral pain.
  • Orthotics . If you have over-pronation in the feet, your doctor may recommend arch supports for your shoes to help correct the arch collapse.

In most cases, patellofemoral pain responds favorably to the above nonoperative treatment program. In severe cases of patellofemoral pain syndrome, however, especially if there is continued pain accompanied by swelling, catching, grinding or evidence of symptomatic scar tissue, your doctor may recommend surgery. Talk with your doctor about the severity of your symptoms and your best options for treatment.

Recovery Outlook
Length of recovery varies from person to person depending on the severity and duration of the patellofemoral pain. Diligence with the treatment measures suggested by your physician and physical therapist will speed the recovery process.

Prevention
Patellofemoral pain can best be prevented by making gradual increases in training programs and activities. It is also important to strengthen and maximize the flexibility of the muscles around the front of the knee, in order to minimize pressure on the patella during activities. Shoes with good arch support are helpful in patients with pronated feet.