Suppose you wanted to build a strong weight bearing structure but needed it to bend without collapsing. How would you do it? Enter the very cleverly designed hinge joint of the knee. The knee, largest joint in the body, joins the thigh bone (femur) to the shin bone (tibia) and includes the small bone alongside (fibula) with the kneecap (patella). Each of the three bones is covered with a tough elastic material that acts as shock absorbers allowing the knee joint to move easily. That’s a lot of complexity within a small area.
The knee bones are connected to the leg muscles by tendons and ligaments inside the knee that allow the leg to bend and extend. They provide stability to the knee and keep it from bending the wrong way. The medial collateral ligament (MCL) provides stability to the inside of the knee; the lateral collateral ligament (LCL) provides stability to the outside of the knee. The anterior cruciate ligament (ACL), in the center of the knee, limits rotation and the forward movement of the tibia and the posterior cruciate ligament (PCL), also in the center of the knee, limits backward movement of the tibia.
What makes all this work are the muscles in the thighs called the quadriceps and hamstrings, connected to the bone by the tough cords of tendons. It’s pretty clever engineering. Inside, the whole surface is covered by a thin membrane which creates fluid to lubricate and provide nourishment to the tissues. In addition to all of this, there are fluid-filled sacs, called bursae, that keep the knee lubricated and help it move smoothly. The range of motion of the knee is limited by the anatomy of the bones and ligaments, but allows around 120 degrees of flexion.
Because the knee is the largest joint and has so much use, it is often the site of pain and injury, particularly in athletes. Ligament injuries to the knee are very common in sports that require stopping and starting or quickly changing directions. Having an evaluation and proper diagnosis are extremely important. Most of these injuries are confirmed with an MRI.
Osteoarthritis (OA) is the most common type of arthritis in athletes caused by a gradual wearing away of joint cartilage causing pain, swelling and decreased range of motion. In the United States alone, more than 27 million adults have a diagnosis of OA.
Knee problems usually occur either from over use as in athletics, or under use as occurs with obesity and inactivity. Overuse injuries occur over time due to stress on the muscles, joints and soft tissues without proper time for healing. If not treated early, the pain can grow into a debilitating injury. Treatment depends on the type of injury, the severity and the individual. Weak muscles and lack of flexibility are primary causes of knee injuries, according to the Mayo Clinic. When the muscles around the kneecap, hip, and pelvis are strong, it keeps the knee stable and balanced, providing support by absorbing some of the stress exerted on the joint.
Now for the part nobody wants to hear. Joint issues are accelerated by Obesity, which can increase forces on the knee up to five times the body weight. A person with obesity is around 60% more likely to develop arthritis than someone of normal body weight.
It stands to reason then, that losing weight is a key element in decreasing pain in the front of the knee but weight loss can be difficult when it hurts to exercise. Exercising in the pool takes the pressure off your joints and still allows your muscles to become stronger.
The body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. If your body mass index (BMI) is greater than 35 or 40, surgery may not be recommended due to a dramatic increased risk of infection, stroke or heart attack. With this much obesity, the surgeon’s technical ability to perform a procedure can be compromised.
A report from the Institute of Medicine revealed that more than 61 million people, nearly 20% of American adults, suffer from knee pain. Since more than two-thirds of Americans are now over weight or obese, those extra pounds greatly increase the stress on the knees which can lead to complications. Women who have a BMI greater than 25 have a significantly higher risk of developing OA compared to women with a normal-range BMI.
Losing weight, even a small amount, is a key element to decrease knee pain and reducing risks for all forms of joint disease. Each pound of weight loss can reduce the knee-joint load by four pounds. Lose just 10 pounds, and that’s 40 fewer pounds per step your knees no longer have to support. Don’t know your BMI? Go to: www.nhlbi.nih.gov/…/ BMI/bmi… Put in your height and weight and it will calculate your measure of body fat. Your doctor or health provider can provide simple diet modifications and recommendations when you visit their office.
Always have your knee pain evaluated if it doesn’t heal within a few days to avoid a longer healing process or chronic problem. The most conservative treatment recommended for all kinds of soft tissue and knee conditions injuries is the R.I.C.E. treatment – Rest (or reducing daily activities), Ice, Compression (as with ace wrap support) and Elevation. Having a normal knee makes life a lot easier.