What is the Patellofemoral Syndrome?

The patellofemoral syndrome is a group of conditions in which the hallmark is pain beneath or surrounding the patella (kneecap). The patella is a unique bone in the leg because it does not directly bear weight. Weight is borne from the femur (thigh bone) through the tibia and fibula, which continue down to the ankle where they form the “dome” of the ankle joint. The patella sits in front of the knee joint and is held, as it were, on a bowstring; the patellar tendon attaches it to the front and is held, as it were, on a bowstring; the patellar tendon attaches it to the front of the tibia below and the quadriceps complex, four powerful thigh muscles, attach it to the hip and femur above. As the knee flexes and extends (bends and straightens), the patella tracks along a groove in the front of the femur. Any factor which disrupts this normal “tracking mechanism” can result in inflammation or pain to the undersurface of the patella. When mild, the undersurface may simply be inflamed. When more severe, the cartilage may actually become damaged or arthritis may develop. When the tracking is poorly controlled or poorly aligned, instability of the patella may result, with subluxation or actual dislocation. Most commonly in athletes, there has been too rapid an increase in training duration, intensity or other sudden changes.

Who is at risk to develop the Patellofemoral Syndrome?

There are several factors which predispose toward this syndrome. It is more common in women, people who are knock-kneed, flat-footed, have excessive flexibility of their joints, or are overweight. The “malicious malalignment syndrome” is characterized by excessive internal rotation of the hips, knock knees, flat feet, with what is known as an increased “Q” angle. The Q angle is the angle hat the quadriceps makes as it encompasses the patella. This puts excess stress on the knees during the course of flexion and extension and results in an increase frequency of symptoms.

What are the symptoms of the Patellofemoral Syndrome?

In its mildest state, patients report stiffness after prolonged sitting or initially in the morning. There is pain around or under the kneecap after activity, especially activities in which there is a lot of knee motion, e.g. ascending or descending steps, bicycling, and running. Symptoms are worsened by prolonged sitting with inadequate legroom, e.g. in a restaurant or movie theater. Patients prefer to sit with their legs extended in front of them. In more serious cases, pain may become constant, there may be subtle swelling around the kneecap, or the patient may sense instability. In cases of malalignment, the kneecap may actually dislocate with activities involving sudden rotation.

How is the Patellofemoral Syndrome treated?

The backbone of long term treatment is quadriceps strengthening to “unload” the initial stress on the patella. This results in reduced pressure behind the patella and improved tracking. Details of quadriceps strengthening are discussed later. Other than exercise, additional treatments include medication, physical therapy, and bracing. Until acute symptoms subside, the patient is advised to avoid or modify those activities which bring on or exacerbate their symptoms. This means no bicycling for a period of time, avoiding frequent usage of steps, and avoiding activities which require squatting or kneeling. It is also recommended that the patient reduce or eliminate running for a period of days to weeks.