Runner's knee: patello-femoral pain syndrome.

You'll often hear this injury referred to as chondromalacia patella. Pain develops when your kneecap doesn't track properly in the groove at the end of your thigh bone (femur) or when there is a muscle imbalance. As a result, the cartilage underneath your patella (kneecap) becomes inflamed, eventually softens, and can then deteriorate and progress to arthritis. This is a very common injury that accounts for many of the overuse injuries treated in sports clinics.

Signs and Symptoms

If you have runner's knee, you'll usually feel pain in the front of the knee and hear cracking and popping noises beneath or on both sides of the kneecap. Symptoms are most prominent when you kneel down, go down stairs, do squats, or do activities that put force against your knee. Stiffness may occur simply from prolonged sitting (sometimes called "moviegoer's knee"). Pain usually increases gradually over a period of time, often a year or longer, until it becomes severe enough that you need to seek medical attention.

Causes

Overpronation. The lower leg rotates inward due to the unstable pronated foot. The kneecap is held to the outside by quadriceps muscles, causing increased pressure. Weak quadriceps. The quadricep muscles normally aid in proper tracking of the kneecap; however, a weak vastus medialis (quadricep muscle closest to the knee on the inside of the thigh) can contribute to the problem.

Muscle imbalances. The most common imbalance occurs when the muscles are stronger on the outside of your leg than those on the inside of your leg. Women usually experience this problem more because their thigh muscles lean toward their knees at a greater angle than in men, who have a narrower pelvic region. A woman's chance of her kneecap being pulled to one side.

Direct or repeated trauma. This could include a fall or blow, or pressure from a prolonged load on your knee, such as during weight training.

Running in the same direction. You may experience pain in the "uphill" knee if you continually run along the same side of the road. The tilt in the road accentuates the pronation of the foot thus resulting in the abnormal tracking of the knee.

RX Measures

* Cut back your running by 50% or more. While recovering, try swimming or other exercises that don't put weight on a bent knee.

* If the knee is painful or swollen, stop activity and rest.

* Use ice treatment for 15 minutes twice daily, especially after activity, to reduce pain and inflammation.

* Try aspirin, naprosyn, or ibuprofen, to reduce swelling and pain.

* Neoprene braces are often helpful to wear during sports or exercise to maintain normal patellar tracking. They are sometimes referred to as patellar stabilizing braces.

To Avoid Future Problems

[square root of] Make sure that knee pain is properly diagnosed (see Running & FitNews, February 1999, "Deciphering Knee Pain" for more help). There can be many reasons for kneecap pain; patello-femoral syndrome is just one possibility.

[square root of] Begin a therapeutic exercise program. This includes stretching and strengthening exercise for the quadriceps (especially the vastus medialis obliqus or VMO, the muscles close to the knee on the inner side of the quadriceps), hamstrings, and calves. Aim to strengthen the quadricep muscles with this dosed-chained exercise: stand with both legs on a step (facing up the stairs). Take your uninjured leg off the step and slowly lower it to the step below. You will be strengthening your vastus medialis obliqus muscle during the first 45[degrees] of this movement.

[square root of] Use orthotic devices to correct abnormal foot mechanics. These can be invaluable to those who overpronate.

[square root of] If you run on roads, don't always run facing traffic. When it's safe, run with traffic so that both legs share the burden of the canted road. But it's best to run on a flat path or track.

RELATED ARTICLE: Runners who always run on the same side of the road are susceptible to patello-femoral pain syndrome.

Patella Femoral Pain Syndrome or Runner's Knee occurs when there is abnormal tracking of the kneecap or stress overload from a training error.

Cross Training

Swimming, biking, water running, cross country skiing, and inline skating

Related Conditions

Plica Syndrome