You have just seen your doctor, and your knee pain has been diagnosed as patellofemoral syndrome (PFS). What does it mean? Keep in mind that it is the most common overuse injury and presents itself mostly in physically active women (2.5 million runners with receive this diagnosis) [i]. Patello-femoral syndrome is described as pain around or under the patella, or the knee cap, that increases when seated for prolonged periods of time or during physical exertion (running, going upstairs, jumping, biking, trekking, etc.). Pain is usually brought on by a change in training intensity, terrain, or footwear.
To understand PFS, one must get to know the knee joint, and the effects of surrounding joints (hip, ankle, and foot). During flexion and extension of the knee, the patella slides in the center of the knee joint, also known as the femoral trochlea. In the case of PFS, the patella strays slightly from its normal trajectory, which compresses it against the femur, thus causing pain.
Altered patellar trajectory can be caused by an imbalance between muscles that glide the knee cap laterally (vastus lateralis of the quadriceps, ilio-tibial band) [ii] versus those that glide it medially (vastus medialis obliquus of the quadriceps). Furthermore, inadequate foot or hip control in weight-bearing activities can contribute to PFS. Excessive compression of the patella is due to a lack of flexibility of the muscles in the front and back of the thigh and leg. A complete physiotherapeutic assessment allows us to determine the causes of pain, and choose the best treatment options/home exercises.
A lot of research has been done on this subject. The following treatment options have shown the most effect on decreasing pain intensity and increasing knee function. A patellar brace can be efficient in centering the patella at the knee joint. Vastus medialis obliquus (quadriceps) activation appears to help realign the patella. In certain patients, wearing foot orthodics helps reduce knee pain by contributing to improved foot alignment. Evaluating the strength of hip abductors and external rotators is paramount. One must make sure the thigh does not have a tendency to migrate inward (in adduction and internal rotation) during walking or running [iii].
In the acute phase, it is important to cease any movements that reproduce pain, as much as possible. Ice application is recommended, as well as use of a walking aid, if necessary. As pain decreases, a gradual return to activities can begin. Improving knee control is also an important part of the rehabilitation process. A meeting with your physiotherapist will assure a speedy return to any activity.
[i] Bergeron, Yves; Fortin, Luc; Leclaire, Richard (2008). Pathologie médicale de l’appareil locomoteur. Montréal : Edisem, 1444 p.
[ii] P.S. Michael. Iliotibial Band tightness and Medial Patellar Glide in Patients with Patellofemoral Dysfunction. JOSPT. March 1993; 17:144-148
[iii] I.S. David, C. Powers. Patellofemoral Pain Syndrome: Proximal, Distal and Local Factors (An International Research Retreat). JOSPT. March 2010; 40:A1-A9