Patellofemoral Pain Syndrome (Also Known As “Runner’s Knee”)

By Rebecca Swope, PT, MSPT

Anterior knee pain is a common complaint among many people, especially among active individuals.  Knee pain is a complex issue that can result from a host of problems.  Approximately 70% of anterior knee pain that comes from patellofemoral disorders will resolve with conservative treatment like physical therapy.¹  Discussed below are some of these problems, causes, symptoms and what is addressed in physical therapy.

Patellofemoral pain syndrome (PFPS) can be a cause of common anterior knee pain, especially among active individuals.  Primary causes of PFPS come from abnormal forces of pull at the knee and overuse with repetitive compressive or shearing forces.  Hip weakness, internal rotation of the femur, pronation at the foot, and/or tightness of muscles in the leg may cause poor control of the knee during activity and can change the forces applied at the knee.  Causes may also come from bony anomalies at the knee, fracture, or osteoarthritis.¹

The patellofemoral joint is comprised of the patella, or knee cap, as it sits over the femoral condyles.  The patella is shaped like a triangle that resides within the patella tendon, which is the tendon that connects the quadriceps muscles to the tibia below the knee.  Its purpose is to protect the knee from trauma and to increase the mechanical advantage of the quadriceps with knee movements.  As the knee flexes and extends, the patella glides inferiorly and superiorly through the trochlear groove.  Should the patella have outside stresses being placed on it, the gliding mechanism will be affected and changes in this can result in causing pain.^{2, 3}

Symptoms of PFPS can include anterior knee pain from a dull ache to sharp stabbing pain with activity.  This pain can be felt anteriorly or deep within the knee, or even a combination of these.  Sometimes a creaking sensation, or crepitus can be felt within the knee.  Often times, activities such as going down stairs, squatting, climbing a hill or prolonged sitting will cause symptoms.^{1, 3}

Your physical therapist will check many things when coming for your first appointment, including strength, muscle length, tenderness around the area, and control of the knee with activities such as squatting.  All of these will give the therapist a better idea of what might be contributing to your knee pain.  Treatment will often include hands on therapy to loosen tight muscles and the area around the knee, strengthening of weak muscle groups, and stretching for tight muscles.  The therapist will also work on reeducating you in movements that involve bending and straightening the knee to reduce your re-injury rate.

Patellofemoral pain is a treatable condition seen frequently in physical therapy that is well managed with conservative methods.

References:

1. Brotzman SB, Wilk KE.  Clinical Orthopaedic Rehabilitation, 2nd ed.  Mosby.  Philadelphia,PA.  2003

2. Wilke KE, Davies GJ, Mangine RE, Malone, TR.  Patellofemoral Disorders: A Classification System and Clinical Guidelines for Non-Operative Rehabilitation.  JOSPT, 1998; 28: 307-322

3. Fulkerson, JP.  Disorders of the Patellofemoral Joint, 3rd ed.  Williams & Wilkins. Baltimore,MD. 1997.

4. Skinner, HB.  Current Diagnosis and Treatment in Orthopedics, 3rd ed.  Lange Medical Books/ McGraw-Hill. New York,NY.  2003.