It's the vital hinge you rarely think about until that one day you do. Maybe it's the twinge you feel while taking that last glide down the ski slope. Or the funny crackling noise your knee makes when you carry the laundry basket downstairs. Whatever the reason, it's a good idea to notice your knees -- and to take care of the joint that takes care of you.
Knee Anatomy: A Primer
The basic structure of the knee consists of four bones held together by four tough, bandlike ligaments. The kneecap, or patella, is able to move back and forth by sliding over a V-shape groove on the thighbone, or the femur.
The quadriceps, the four muscles on the front and sides of each thigh, and the hamstring muscle group, which runs behind them, support the knee and determine how well the joint responds to movement -- or to walking, running, and skiing.
Other important players include tendons, which attach muscles to bones; cartilage, which helps cushion the ends of bones and acts as a shock absorber; and synovial fluid, which is the knee's "motor oil."
What's That Clicking Sound?
Knee pain is common in women approaching midlife, says Jo Hannafin, an orthopedic surgeon and a cofounder of the Women's Sports Medicine Center at the Hospital for Special Surgery, in New York City. Weight gain is one of the most common causes. Other culprits include too little exercise and, conversely, intense weekend-warrior activity. Too much of a single type of exercise can also strain the knees.
Pain surfaces in different parts of the joint, and the location of the sore area can provide clues. Here are some common knee problems and their symptoms.
Anterior Cruciate Ligament Sprains
Injuries to the anterior cruciate ligament (ACL), a band inside the knee that helps stabilize the joint, are typically caused by sudden twists of the knee. They are often accompanied by a popping sensation, followed by pain and perhaps a feeling that the knee is giving out. For reasons that are not fully understood, women participating in sports are seven times more likely than men to experience noncontact injuries to the ACL.
Many ACL sprains are initially treated with simple remedies such as rest, ibuprofen, and ice packs. But full recovery may require surgery to reconstruct the ligament, as well as an extensive course of physical therapy.
Iliotibial Band Syndrome
The iliotibial band (ITB) is a fibrous cord that extends from the thigh to the shin. When it's too tight, it can rub against the thighbone, resulting in sharp pain or a dull ache on the lateral (outward) side of the knee and possibly the thigh as well. Cyclists and runners -- two athletic groups susceptible to ITB syndrome -- often experience the pain 10 to 15 minutes into exercise.
Stretching can help, says Lewis Maharam, medical director for the New York City Marathon. A physical therapist can recommend specific stretches that will target the ITB and the muscles that affect its position. Orthotics are another option, Maharam says. Specially designed shoe inserts can correct the body's alignment and reduce friction of the ITB.
A C-shape piece of cartilage between the thighbone and the shinbone, the meniscus acts as a shock absorber for the knee. In young people, meniscus injuries tend to occur only after significant trauma. But in people older than 40, for whom age-related degeneration is setting in, tearing can occur more easily, usually when the knee is forced to make a rapid twisting motion. The hallmark of a meniscus tear is a "pop," sharp pain, and sometimes an inability to straighten the leg. Swelling and tenderness of the knee are also symptoms.
Meniscus tears have a poor track record for healing. If basic treatments such as ice packs and ibuprofen don't reduce pain, an arthroscopic procedure may be necessary to repair the tear or remove damaged tissue.
Osteoarthritis of the Knee
Characterized by a dull ache and feelings of stiffness, osteoarthritis may surface as the knee's cartilage wears down with use and age. The pain is often sharpest when the sufferer walks down stairs or an especially steep incline. The downward pull forces the knees to experience pressure equal to five times a person's body weight.
Weight gain is one of the most significant causes of knee discomfort, and being even 10 pounds overweight can have an impact. Maintaining a healthy weight can significantly reduce knee pain, as can conditioning muscles that support the knee.
Tendinitis of the Knee
Repetitive activities, including running, cycling, or jumping, can inflame the tendons of the knee. Squatting and kneeling can also exacerbate the condition. Tendinitis hurts not only at the moment the injury is caused but may persist even when the knee is not active. Pain below the kneecap suggests patellar tendinitis; soreness above it may signal quadriceps tendinitis. Healing requires a fine balance of rest and exercise. The tendons need time to heal, followed by exercises that gradually increase flexibility and build leg muscles, which will reduce strain on the tendons.
Heredity is often to blame for this one. Runners who overpronate (their feet roll inward during a stride) or who have flat feet or a second toe longer than the big toe, can experience soreness and knee clicking and sometimes feel as if their knee is about to give out, Maharam says. "It bothers them more going down stairs. And if they are sitting for a long time, the knee feels stiff." Such symptoms come about when the kneecap does not track over the V-shape groove behind the knee smoothly, but scrapes along the lateral side of the groove.
A doctor may recommend orthotics to correct a runner's stride. But it's also necessary to strengthen the medial quadriceps, which hold the kneecap in the center of the groove.
Scheduling time for regular exercise is the key to keeping knees in good form, says Elizabeth Arendt, professor and vice chairwoman of the Department of Orthopedic Surgery at the University of Minnesota.
In particular, doctors recommend programs that focus on flexibility and core strength training, such as yoga and Pilates. But they say benefits also lie in doing specific exercises daily that keep leg muscles limber and strong. Here are four that Hannafin recommends -- two for flexibility and two for strength.
While standing, prop one bent leg on a table or chair. Lean your upper body forward so you feel a stretch in your buttocks and thigh. Hold for 30 seconds. Perform two to four times on each side.
Prop your leg on a chair. Stand tall and straight, with your stomach pulled tight. Bend forward at the hip, keeping the leg and back straight enough so you feel the muscles stretch behind your thigh and knee. Hold for 30 seconds. Perform two to four times on each side.
Lie down with your lower back pressed to the floor. Bend one leg and straighten the other. Lift the straight leg 6 to 8 inches; hold for five seconds, and then lower. Do three sets of 10 to 15 lifts. (An ankle weight can provide more resistance.)
With your feet shoulder-width apart, bring the left foot to rest slightly above the right knee. Raise your arms. Hold, and focus on keeping your balance. Switch, and repeat.
Text by Maura Casey