Patellofemoral pain syndrome (PFPS) is a syndrome characterized by pain or discomfort seemingly originating from the contact of the posterior surface of the patella (back of the kneecap) with the femur (thigh bone). It is the most frequently encountered diagnosis in sports medicine clinics.
Make sure your running shoes:
Are made well
Have good cushion
With this injury it usually takes a couple of weeks to get back running and another couple to get the confidence that the injury will not recur. However stretching should continue long after the injury heals or you may find the injury returns. Regular sports massage may prevent this injury from happening.
My physical therapist recommended that I support my kneecap by strengthening my quadriceps (thigh) muscles and that I stretch the iliotibial band, a long band of connective tissue that runs from the knee to the hip. When that tendon is too tight, it pulls the kneecap off to one side. I also decided to vary my exercise routine.
To prevent PFPS, run on softer surfaces, keep mileage increases less than 10 percent per week, and gradually increase hill work in your program. Visit a specialty running shop to make sure you're wearing the proper shoes for your foot type and gait. Also, strengthening your quadriceps will improve patellar tracking, and stretching your hamstrings and calves will prevent overpronation.
This may happen because:
You have flat feet
The kneecap and the two other bones that make up the knee joint don't line up well (this is called poor alignment of the patellofemoral joint)
There is tightness or weakness of the muscles on the front and back of your thigh
You've done too much activity, which places extra stress on the kneecap (such as running, jumping or twisting, skiing, and playing soccer)
Anyone can get patellofemoral pain syndrome, but for some reason it is more common in women than men—especially in mid-life women who’ve been running for many years. The problem, say researchers who just published a study in the journal Gait and Posture, is that lots of “mature” women develop alignment problems with their knees.
The condition may result from acute injury to the patella or from chronic friction between the patella and the groove in the femur through which it passes during motion of the knee.
In some people with runner's knee, the kneecap is out of alignment. If so, vigorous activities can cause excessive stress and wear on the cartilage of the kneecap. This can lead to softening and breakdown of the cartilage on the patella (chondromalacia patella) and cause pain in the underlying bone and irritation of the joint lining.
Symptoms of runner's knee are:
Pain behind or around the kneecap, especially where the thighbone and the kneecap meet.
Pain when you bend the knee -- when walking, squatting, kneeling, running, or even sitting.
Pain that's worse when walking downstairs or downhill.
Popping or grinding sensations in the knee.
Forty-two percent of all overuse injuries affect the knee joint, and patellofemoral pain syndrome (PFPS), or simply "runner's knee," is the most common overuse injury among runners. It occurs when a mistracking kneecap (patella) irritates the femoral groove in which it rests on the thighbone (femur).