What is a Patellofemoral Injury?

The knee is the largest and one of the most complex joints in the human body. It consists of 4 bones, multiple ligaments, muscles and tendons, cartilage and soft tissue. The knee is a modified hinge joint allowing primary motions of knee flexion and extension. The joint and its components function together to provide stability and power for activities of daily living and athletic movements. However, any of these structures can be injured or damaged requiring treatment as easy as bracing, rest and therapy to as complex as surgery to correct. Regardless, either treatment will typically allow a full return to activity or sports without additional complications.

The boney structures of the knee consist of the patella (knee cap), Femur (thigh bone), Tibia and Fibula (lower leg bones). The patella glides with knee flexion and extension within the trochlear groove. Gliding of this area is accomplished through articular cartilage, one of the two types of cartilage within the knee complex. Articular cartilage is the protective covering over the ends of the bones. This allows the joint to glide permitting fluid motion during active and passive activities.

The gliding motion of the patella is stabilized with the additional soft tissue structures such as ligaments, muscles, tendons, synovial tissue and the fat pad beneath the patella. Patellofemoral ligaments are connective bands that stabilize the joint from unwanted movements such as subluxations and dislocations. The lateral and medial patellofemoral ligaments, as seen below, are the main two stabilizing ligaments of the patella.