Patellofemoral Pain Syndrome

Patellofemoral pain syndrome symptoms

Symptoms of patellofemoral pain syndrome are an aching pain in the knee joint, particularly at the front of the knee around and under the patella. There will be 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.

Other signs a sports medical practicioner 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 including calf muscles, hamstrings, quadriceps (especially vastus lateralis on the outside) and iliotibial band. With assessment a Q-angle greater than 18 to 20 degrees is often seen. The Q angle is the ankle between the quadriceps and the patella tendon which would indicate mal tracking of the patella.

Causes of Patellofemoral Pain Syndrome

When bending and straightening the knee, several muscles surrounding the joint act together to cause the patella to run in a straight line within the intercondylar groove, formed by the Femur and Tibia. If any of the structures are particularly tight or weak, this causes an imbalance which can result in the patella mal-tracking.

The most common example of this is when the lateral (outer) 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. This results in the patella moving too far laterally (to the outside) as the tight structures pull it across and the muscles on the inside are not strong enough to control this force.

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 - Bending the knee increases the pressure between the patella and the femur. Thus sports such as running, where repeated weight-bearing occurs, may result in PFPS.
• Over pronating Feet - Pronating or flat feet lead cause the lower leg to rotate inwards more than normal which causes the knee to rotate inwards affecting the alignment of the patella.
• Q-angle - Some people have a larger than normal angle between the quadriceps and the patella tendon known as the Q angle. When the athlete straightens their leg when weight bearing, the patella will be forced to the outside of the knee. With repeated bending and loading, this motion may lead to damage of the underlying structures and cause pain. A larger Q angle is common in women due to their wider pelvis. This is why more women suffer with this condition than men.

PFPS is often confused with another condition known as Chondromalacia Patellae (CMP). This is damage to the cartilage which lines the underside of the knee cap. CMP can be a result of PFPS, although it can also occur independently, usually due to damage from an impact.

Who is Most at Risk From Patellofemoral Syndrome?

• You are more prone to this if you have a small kneecap or one that sticks out If your feet roll in or pronate.
• If you suffer with tight muscles.
• If you have weak quadriceps muscles.
• Athletes who do a lot of long distance running or hill running.
• Those who have had a previous knee dislocation

Runners Knee Treatment

What can the athlete do?

• Apply RICE (Rest, ice compression and elevation) after activity. This will help reduce pain and swelling.
• Rest until there is no pain (this is very important).
• 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.

What can a Sports Injury Professional do?

• Confirm the diagnosis and rule out other conditions which may have similar symptoms such as a synovial plica. This is a fold in the synovial membrane in the knee causing pain on the kneecap.
• Prescribe anti-inflammatory medication e.g. ibuprofen. Ibuprofen should not be taken if you have asthma. Always check with a doctor before taking any medication.
• Prescribe a comprehensive rehabilitation program for patellofemoral pain syndrome consisting of stretching and strengthening exercises which are usually done conjunction with patellofemoral taping techniques.
• Use sports massage to loosen tight structures and muscles which may be causing the patella tracking problems.
• Advise on patellofemoral pain syndrome exercises especially for the vastus medialis muscle on the inside of the knee and stretching exercises for the outside of the knee.
• Perform gait analysis to determine if you overpronate and prescribe orthotic inserts to correct the foot biomechanics.
• Operate in chronic cases to release the tight lateral structures.
• PFPS can be caused by a number of biomechanical problems, starting with the feet. Ensure that you have the right running shoes for your style. See a podiatrist or running specialist for advice on running shoes.