What Is Patellofemoral Ligament Reconstruction?

Patellofemoral ligament reconstruction is a type of surgery carried out when the kneecap, or patella, becomes unstable. This is usually the result of an injured ligament which is no longer holding the patella in place. Ligaments are tough tissue bands and the patellofemoral ligaments fix the sides of the patella to the lower end of the femur, or thigh bone. During patellofemoral ligament reconstruction, the torn ligament is replaced using a tendon, a strap of tissue that attaches muscle to bone, taken from another part of the body. Once the tendon is fixed in place instead of the ruptured ligament, it should prevent the patella from dislocating.

Typically, a patellofemoral ligament is torn when the knee is twisted to the outside. As a result, the strained ligament is commonly the one on the inside of the knee. This is known as the medial patellofemoral ligament and, once it has torn, the patella tends to move toward the outside of the knee joint. Symptoms of knee deformity, pain, swelling and bruising may be associated with a feeling of the knee giving way. If the ligament fails to heal after the knee has been immobilized for a while and after a program of supervised exercises has been carried out, patellofemoral ligament surgery becomes necessary.

Before patellofemoral ligament reconstruction, a tendon graft is taken from the hamstring tendons, which are located at the back of the knee. The surgeon removes the tendon through a small cut. A general anesthetic is used during the operation, which means the patient is not conscious.

During patellofemoral ligament reconstruction, a slender, flexible instrument known as an arthroscope is passed into the knee. The arthroscope has a camera which enables the surgeon to view the interior of the knee joint. Three small cuts are made, through which the arthroscope can be inserted into the knee, enabling the surgeon to view all of the joint. A drill attached to the arthroscope is used to cut a channel through the patella, and one end of the hamstring tendon is threaded through it. Another channel is cut into the femur, into which both ends of the tendon are inserted and fixed in place with a screw.

After patellofemoral ligament reconstruction, patients are encouraged to move around as soon as possible and to practice exercises to strengthen the muscles that support the knee. Complications such as swelling, pain and numb skin may sometimes be experienced following surgical ligament treatment. Physiotherapy can help to reduce knee pain and build up wasted muscles.