Your knees are put under a lot of stress, whether you’re running, playing basketball, dancing, or simply cleaning your house. Just using the stairs can put pressure on each knee equal to four times your body weight.
Functioning simultaneously as a hinge, lever, and shock absorber, the knee is the key to your ability to stand up, walk, climb, and kick. Yet it depends almost entirely on soft tissue—ligaments, tendons, and muscles—for stability. Because of its complexity and the great forces to which it is routinely subjected, the knee is susceptible to a host of injuries.
Of all chronic knee injuries caused by overuse, runner’s knee—more accurately called patellofemoral pain syndrome, or PFPS—is the most common.
Prevention is the key
PFPS typically occurs when a misaligned kneecap (patella) irritates the connective tissue supporting the knee. Characterized by dull pain in or around the kneecap, it is most noticeable when you go down stairs, run, or squat.
Nearly 30 percentof runners eventually develop this disorder. Skiers, cyclists, soccer players and people who participate in any high-impact activities are also prone to it.
Research has shed light on a variety of underlying factors that can contribute to PFPS. These include biomechanical problems such as a kneecap sitting too high or tilted in the groove in which it rests on the thighbone (femur); knees that turn in too much; feet that are very flat or very highly arched; and various muscle-related issues that affect how the kneecap moves. Genetics may predispose you to some of these factors.
Women are at greater risk for PFPS than men for anatomical reasons. For instance, they have a wider pelvis, which increases the angle of the quadriceps (the large four-part muscle group on the front of the thigh) to the knee. They also have smaller knees with less restraining tissue and weaker supporting muscle.
The best way to prevent runner’s knee is to strengthen and stretch the muscles that power knee movement, especially the quadriceps and hamstrings, which are located in the back of the thigh. A weakness or imbalance in the quads, hamstrings, and/or hip muscles can contribute to improper tracking of the kneecap.
If you’re a runner, your quadriceps are probably weaker than your hamstrings, so it’s a good idea to alternate cycling (a good way to strengthen the quads) with running. Walking up stairs or hills also helps strengthen the quadriceps.
To protect your knees, avoid the following:
- Deep lunges or full squats
- Downhill running
- Cycling with the seat too low or in too high a gear
- Taking large steps on the stairs or a stair-climbing machine
- Full leg extensions with heavy weights and locked knees
In addition, do not exercise in worn-out shoes; don’t suddenly increase the intensity or length of your workouts; and don’t run on very hard, very soft, or hilly terrain. Don’t wear high heels, except on special occasions.
Treatment: what’s right for you?
If you have knee pain for more than a week or two, see your doctor. If you have PFPS, you should be referred to a physical therapist. There has been much debate about which treatments are best for PFPS.
Taping: One rehab technique for correcting a kneecap that doesn’t track properly is called McConnell taping, in which special tape is used to pull the cap into the correct position, thus reducing pain and allowing people to engage in rehab exercises. However, there is a need for large studies on taping techniques, and not all the findings have been positive. In addition, many people have trouble applying the tape properly.
Braces: There are special knee braces or sleeves that are supposed to correct knee biomechanics. The compression also stimulates skin and muscle receptors, thereby improving proprioception—that is, how you perceive the position of your knee in space. Improved proprioception may allow you to modify your movement in a way that puts less stress on the knee joint. A review in the American Family Physician concluded, however, that it’s not clear how effective the braces are.
Bottom line: If you have PFPS, it’s crucial to determine what’s causing it and get a personalized treatment plan. A skilled physical therapist—especially one who works with athletes and dancers—can then develop an exercise program to address your specific muscle weaknesses or imbalances and/or biomechanical problems.
Not everyone with PFPS has weak quads, hamstrings or hip muscles, for example. If it’s a biomechanical problem in the feet, you may need special shoe inserts. In rare cases, if nothing else helps, surgery may be an option.
This article first appeared in the UC Berkeley Wellness Letter.
Originally published on BerkeleyWellness.com on November 2010. Updated April 2013.