Got knee pain? Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain in adolescents and adults younger than 60 years. Commonly referred to as “runner’s knee,” PFPS is defined as pain occurring around or behind the patella that is aggravated by at least one activity that loads the patella (i.e. kneecap) during weight-bearing on a flexed knee.
Pain related to PFPS can be caused by overuse from vigorous physical activities that put repetitive stress on the knee (running, jogging, squatting, and climbing stairs) or by a sudden change in physical activity. This change may include the frequency of activity (how often), the duration (how long), or the intensity (how hard or how fast). Other factors may include use of improper sports training techniques or equipment, changes in footwear or playing surface, and patellar malalignment (abnormal tracking of the kneecap).
Risk factors for developing PFPS include female sex, dynamic knee valgus (knees that cave in when you squat or bend your knee), flat feet, overuse or sudden increase in physical activity level, patellar instability, weakness in the quadriceps muscles, and activities such as running, squatting, hiking, and climbing up and down stairs.
PFPS is common in both youth athletes and recreational exercisers who increase their activity level during the warmer months here in New England. Diagnosis is based on patient history and physical examination. Imaging of the knee with x-ray is not necessary to diagnosis PFPS, but may be helpful in ruling out other causes of knee pain, such as patellar fracture or osteoarthritis. Structural abnormalities are not associated with PFPS, therefore, MRI is not recommended.
The cornerstone of PFPS treatment is individualized physical therapy. In fact, exercise therapies are the most effective treatment for improving short- and long-term pain in patients with PFPS. Depending on the individual, corrective exercises in the physical therapy setting may include core muscle strengthening, pelvic stabilization, intrinsic foot strengthening and stability to develop the arch of the foot, quadriceps strengthening, hamstring stretching, and learning proper techniques for running, jumping, and squatting. These exercises translate well to everyday activities such as sitting in or rising from a chair and climbing stairs. Corrective exercises should be continued as a home exercise program for long-term pain relief and improved functionality.
Nonsteroidal anti-inflammatory medications (Ibuprofen, Motrin, Naproxen, Aleve) may improve pain in patients with PFPS, but the effect may be limited to one week. Long term use of these medications is not recommended.
Patellar kinesiotaping may provide short term pain relief by improving patellar maltracking, however, it is most effective when used in combination with a physical therapy program. Knee braces have not demonstrated benefit over exercise. Foot orthotics can help to correct dynamic knee valgus (knee cave) in some patients, although it is unclear if they reduce knee pain. Surgery is rarely indicated.