Knee Deep: Anatomy, Arthritis and Age


According to the American Academy of Orthopedic Surgeons, approximately 5 million people seek medical treatment each year for knee problems, with 1 in 6 developing knee pain by age 45 and 50% by age 60. 2 out of every 3 people that are obese will develop symptomatic knee problems and 750,000 undergo knee replacements in the U.S. annually.

Arthritis of the knee, most often osteoarthritis, is a degenerative disease where cartilage in the joint gradually wears away. In rheumatoid arthritis, the knee joint becomes inflamed and cartilage may be destroyed completely. Arthritis not only affects joints, but supporting structures like muscles, ligaments and tendons. Osteoarthritis, which affects 28 million Americans a year is common and often results from wear and overuse. Other common knee problems result from injury, such as a blow to the knee or a sudden shift in movement that strains the knee beyond its normal range of movement.

A person who has arthritis of the knee may experience pain, swelling and a decrease in motion. Morning stiffness is a common symptom that lessens after movement. Sometimes the knee joint locks or clicks when the knee is bent and straightened, but these signs may also occur in other knee disorders. The doctor may confirm the diagnosis with a physical exam and x-rays which will show a loss of joint space.

Most often osteoarthritis of the knee is treated with analgesics, pain-reducing medication, such as aspirin or acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or topical analgesics, like BioBlast 6 Hour Pain Gel, that contain all natural herbal alternatives to the required daily consumption of pain pills that may be harmful to the kidney and liver. Exercise to restore joint movement and strengthen the knee is also recommended as is losing excess weight. Rheumatoid arthritis of the knee may require a more aggressive treatment plan that includes physical therapy and prescription pharmaceuticals. A seriously damaged knee joint due to arthritis may need to be surgically replaced with an artificial one.

Knee problems resulting from an accident, however, are unforeseeable and cannot be prevented. However, basics steps can be taken to prevent many knee injuries and developing conditions. Warm up by walking or riding a stationary bicycle to help increase blood flow and oxygen, then stretch before exercise or participating in sporting activities to help loosen and elongate muscle tissue. Stretching the quadricep and hamstring muscles reduces tension on the tendons and relieves pressure on the knee during activity. Performing specific exercises will strengthen the muscles of the leg, such as stair climbing, incline walking and riding a stationary bike. Weight training is another pathway to strengthening leg muscles that benefit the knee. Avoid sudden changes in intensity of exercise and increase the force and or duration of activity gradually.

To maintain proper leg alignment when walking or running wear shoes that both fit and are in good condition. Knee problems can be caused by flat feet or over-pronated feet, feet that roll inward and orthotics can help those affected by these foot conditions to reduce biomechincal issues. Obesity increases the risk of degenerative wearing conditions such as osteoarthritis of the knee so maintaining optimal bodyweight and intake control will reduce stress on the knee.

The knee joint works like a hinge to bend and straighten the lower leg. This hinge-like action permits people to sit, stand and pivot. The knee joint is a junction of bone and cartilage and consists of three bones. The femur also known as the thigh bone or upper leg bone, the tibia or shin bone and the patella or kneecap. The patella is approximately 2 to 3 inches wide and 3 to 4 inches long. It sits over the other bones at the front of the knee joint and slides when the leg moves, protecting the knee while leveraging the muscles.

The ends of the three bones in the knee joint are covered with articular cartilage, a tough, elastic material that helps absorb shock and allows the knee joint to move smoothly. Separating the bones of the knee are pads of connective tissue called menisci, which are divided into two crescent-shaped discs positioned between the tibia and femur on the outer and inner sides of each knee. The two menisci in each knee act as shock absorbers, cushioning the lower part of the leg from the weight of the rest of the body, as well as enhancing stability.

There are two muscles intersecting at the knee. The quadriceps muscle comprises four muscles on the front of the thigh that work to straighten the leg from a bent position while he hamstring muscles, which bend the leg at the knee, run along the back of the thigh from the hip to just below the knee.

Ligaments are strong, elastic bands of tissue that connect bone to bone. They provide strength and stability to the joint. There are four key ligaments of the knee, connecting the femur and tibia. The anterior cruciate ligament or ACL, is located in the center of the knee and limits rotation and forward movement of the tibia. The medial collateral ligament or MCL provides stability to the medial or inner aspect of the knee. The posterior cruciate ligament or PCL, like the ACL, is also located in the center of the knee, but limits backward movement of the tibia. Finally, the lateral collateral ligament or LCL provides stability to the lateral or outer aspect of the knee. The knee capsule, which is a protective fiber-like structure that wraps around the knee joint does contain other ligaments. Inside the capsule, however, the joint is lined with a thin, soft tissue, called synovium.

Tendons are tough cords of tissue that connect muscle to bone. In the knee, the quadriceps tendon connects the quadriceps muscle to the patella and provides power to extend the leg. The patellar tendon, technically a ligament, connects the patella to the tibia.