Patellofemoral Pain Syndrome

Patellofemoral Pain Syndrome (PFPS) also known as runners knee is a generic term used to describe pain at the front of the knee which comes on gradually with symptoms increasing over a period of time.

Patellofemoral pain syndrome symptoms

Symptoms of patellofemoral pain syndrome include an aching pain in the knee joint, particularly at the front of the knee around and under the patella. There is often tenderness along the inside border of the kneecap and swelling will sometimes occur after exercise. Patellofemoral pain is often worse when walking up and down hills or sitting for long periods of time. Pain under the kneecap when sitting still for a while is known as the theatre sign or movie-goers knee.

Patellofemoral pain syndrome explained

Patellofemoral painPatellofemoral pain syndrome is sometimes also called anterior knee pain or runners knee and occurs when the patella does not move or track correctly as the knee is being bent and straightened. This can lead to damage to the cartilage on the underside of the patella itself resulting in pain and inflammation. Patellofemoral pain is common in people who do a lot of sport, in particular adolescent girls.

Other signs a sports medical practitioner may pick up include a click or cracking sound when bending the knee, wasting of the quadriceps muscles if the injury is an old one and tight muscles around the knee joint.

Q angle of the kneeWhen bending and straightening the knee, several muscles surrounding the joint act together to cause the patella to run in a straight line within a groove formed by the femur and tibia bones called the intercondylar groove. If any of the structures are particularly tight or weak, this causes an imbalance which can result in the patella being pulled out of line, usually towards the outside of the knee.

The most common example of this is when the lateral structures of the knee including the vastus lateralis, iliotibial band and lateral retinaculum are tight and the vastus medialis oblique muscle on the inside of the knee is weak. The Q angle is the ankle between the quadriceps and the patella tendon and a Q-angle greater than 18 to 20 degrees could indicate patella tracking problems. A larger Q angle is common in women due to their wider pelvis.

Patellofemoral pain syndrome can also occur following a knee injury if the muscles of the quadriceps, especially the vastus medialis on the inside become inhibited or considerably weakened. Other factors which can cause patellofemoral pain include overloading such as running with weight and over pronation feet which cause the knee to rotate inwards.

CMPPFPS is often confused with another condition known as chondromalacia patellae  or CMP for short. This is damage to the cartilage which lines the underside of the knee cap and can result from patellofemoral pain, although it can also occur independently, usually due to damage from an impact. You are more prone to this if you have a small kneecap or one that sticks out, if your feet roll in or pronate, you have tight muscles, do a lot of long distance running or have had a previous knee dislocation.

Runners knee treatment

Patella stablizing knee braceApply RICE (Rest, ice compression and elevation) after activity. This will help reduce pain and swelling. Rest until there is no pain. Wear a runners knee brace or support which will help control patella tracking. These will usually have a hole in the middle for the kneecap and often straps which are pulled across the knee applying support to the patella. See a sports injury professional who can advise on treatment and patellofemoral pain syndrome rehabilitation.

A professional practitioner can confirm the diagnosis and rule out other conditions which may have similar symptoms such as a synovial plica. A doctor may prescribe anti-inflammatory medication e.g. ibuprofen. Ibuprofen should not be taken if you have asthma.

Heel dropsA comprehensive rehabilitation program for patellofemoral pain syndrome consisting of stretching and strengthening exercises should be done, often in conjunction with patellofemoral taping techniques. Sports massage can help loosen tight structures and muscles which may be causing the patella tracking problems. Gait analysis can be done to determine if the athlete overpronates and orthotic inserts can correct poor foot biomechanics. In chronic cases a surgeon may operate to release the tight lateral structures of the knee.