Knee problems

Definition

Post-traumatic knee care is the treatment of knee problems caused by physical trauma, such as an injury, stress , or long-term overuse.

Description

Because of its complex structure and weight-bearing capacity, the knee is the most commonly injured joint among older adults. Knee injuries can range from mild to severe. Some of the less severe, yet still painful and functionally limiting, knee problems include runner's knee (pain or tenderness close to or under the knee cap at the front or side of the knee), iliotibial band syndrome (pain on the outer side of the knee), and tendonitis, also called tendinosis (marked by degeneration within a tendon, usually where it joins the bone). More severe injuries include bone bruises or damage to the cartilage or ligaments. Knee injuries can occur as the result of a direct blow or sudden movements that strain the knee beyond its normal range of motion. Sometimes knees are slowly injured over time due to normal wear and tear. The knee is a joint and is composed of bones, cartilage, ligaments, tendons, and muscles. The ends of the three bones in the knee joint are covered with articular cartilage, a strong, 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. The menisci are two crescent-shaped discs (each called a meniscus) positioned between the tibia (shin bone) and femur (thigh bone) 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 and enhancing stability. There are two groups of muscles at the knee. The four quadriceps muscles on the front of the thigh work to straighten the knee from a bent position. The hamstring muscles, which run along the back of the thigh from the hip to just below the knee, help to bend the knee.

The quadriceps tendon connects the quadriceps muscle to the patella and provides the power to straighten the knee. The following four ligaments connect the femur and tibia and give the joint strength and stability:

• The medial collateral ligament (MCL), which runs along the inside of the knee joint, provides stability to the inner (medial) part of the knee.
• The lateral collateral ligament (LCL), which runs along the outside of the knee joint, provides stability to the outer (lateral) part of the knee.
• The anterior cruciate ligament (ACL), in the center of the knee, limits rotation and the forward movement of the tibia.
• The posterior cruciate ligament (PCL), also in the center of the knee, limits backward movement of the tibia.

Among the most common knee injuries in older adults are osteoarthritis , meniscal injuries, cruciate ligament injuries, medial and lateral collateral ligament injuries, and tendon injuries.

Osteoarthritis

Most people with knee problems have a form of arthritis called osteoarthritis. In this disease, the cartilage gradually wears away and changes occur in the adjacent bone.

Meniscal injuries

The menisci can be easily torn by the force of rotating the knee while bearing weight. If the tear is tiny, the meniscus stays connected to the front and back of the knee; if the tear is large, the meniscus may be left hanging by a thread of cartilage. The seriousness of a tear depends on its location and extent.

Ligament injuries

These are sometimes referred to as sprains. They don't necessarily cause pain, but they are disabling. A sprain is a stretch or tear of a ligament, the band of connective tissues that joins the end of one bone with another. Sprains can range from first degree (minimally stretched ligament) to third degree (a complete tear).

Tendon injuries

Knee tendon injuries range from tendinitis (inflammation of a tendon) to a ruptured (torn) tendon. They are usually not severe but are still painful and functionally limiting knee problems.

Demographics

Nearly 20 million Americans were treated for knee injuries in 2003, according to the American Academy of Orthopaedic Surgeons (AAOS). In the United Kingdom, there were 68,805 hospital visits in 2002–2003 due to knee injuries. The most common knee injury in the elderly is osteoarthritis followed by blunt trauma to the knee, such as a fall or striking the knee against a hard surface.

Causes and symptoms

Osteoarthritis

Osteoarthritis may be caused by joint injury or being overweight. It is associated with aging and most typically begins in people age 50 years or older. Symptoms include pain, inflammation, stiffness, and a decrease in the range of motion.

Meniscal injuries

A partial or total tear may occur when a person quickly twists or rotates the upper leg while the foot stays still (for example, when dribbling a basketball around an opponent or turning to hit a tennis ball). Generally, when people injure a meniscus, they feel some pain, particularly when the knee is straightened. If the pain is mild, the person may continue moving. Severe pain may occur if a fragment of the meniscus catches between the femur and the tibia. Swelling may occur soon after injury if there is damage to blood vessels. Swelling may also occur several hours later if there is inflammation of the joint lining (synovium). After any injury, the knee may click, lock, feel weak, or give way. Although symptoms of meniscal injury may disappear on their own, they frequently persist or return and require treatment.

Ligament injuries

Sprains are caused by trauma such as a fall or blow to the body that knocks a joint out of position and, in the worst case, ruptures the supporting ligaments. Signs of a sprain include varying degrees of tenderness or pain; bruising ; inflammation; swelling; inability to move the knee; or joint looseness, laxity, instability, and loss of strength. While it's hard to tell the difference between mild and moderate strains, severe strains not treated professionally can cause damage and loss of function.

Tendon injuries

If a person overuses a tendon during certain activities such as dancing, cycling, or jogging, the tendon stretches and becomes inflamed. Tendinitis of the patellar tendon is sometimes called jumper's knee because in sports that require jumping, such as basketball, the muscle contraction and force of hitting the ground after a jump strain the tendon. After repeated stress, the tendon may become inflamed or tear. People with tendinitis often have tenderness at the point where the patellar tendon meets the bone. In addition, they may feel pain during running, hurried walking, or jumping. A complete rupture of the quadriceps or patellar tendon is not only painful, but also makes it difficult for a person to bend, extend, or lift the leg.

Diagnosis

Doctors diagnose knee problems based on the findings of the patient's medical history, physical exam, and diagnostic tests. During the medical history, the doctor asks how long symptoms have been present and what problems the patient is having using their knee. In addition, the doctor will ask about any injury, condition, or health problem that might be causing the problem. During the physical exam, the doctor bends, straightens, rotates, or presses on the knee to feel for injury, and determines how well the knee moves and where the pain is located. The doctor may ask the patient to stand, walk, or squat to help assess the knee's function.

Depending on the findings of the medical history and physical exam, the doctor may use one or more tests to determine the nature of a knee problem. Some of the more commonly used tests include:

• X ray—A procedure in which an x-ray beam is passed through the knee to produce a two-dimensional picture of the bones.
• Computerized axial tomography (CAT) scan—A procedure in which x rays are passed through the knee at different angles, detected by a scanner, and analyzed by a computer. CAT scan images show soft tissues such as ligaments or muscles more clearly than conventional x rays. The computer can combine individual images to give a three-dimensional view of the knee.
• Bone scan—A technique that creates images of bones on a computer screen or on film. Before the procedure, a harmless radioactive material is injected into the bloodstream. The material collects in the bones, particularly in abnormal areas of the bones, and is detected by a scanner.
• Magnetic resonance imaging (MRI)—A procedure that uses a powerful magnet linked to a computer to create images of areas inside the knee. During the procedure, the leg is placed in a cylindrical chamber where energy from a powerful magnet (rather than x rays) is passed through the knee. An MRI is particularly useful for detecting soft tissue damage.
• Arthroscopy—A surgical technique in which the doctor manipulates a small, lighted optic tube (arthroscope) that has been inserted into the joint through a small incision in the knee. Images of the inside of the knee joint are projected onto a computer-like monitor.
• Joint aspiration—A procedure in which a doctor uses a syringe to remove fluid buildup in a joint, and can reduce swelling and relieve pressure. A laboratory analysis of the fluid can determine the presence of a fracture, an infection, or inflammation.
• Biopsy—A procedure in which a piece of tissue is surgically removed from the knee and examined under a microscope.

Treatment

Osteoarthritis

Treatment is targeted at relieving symptoms and may include pain medicines such as aspirin or acetaminophen (Tylenol); nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin, Nuprin, Advil); or in some cases injections of corticosteroid medications directly into the knee joint. Other treatments for the pain of knee osteoarthritis include injections of hyaluronic acid substitutes and the nutritional supplements glucosamine and chondroitin sulphate.

QUESTIONS TO ASK YOUR DOCTOR

• What treatment options are there for my knee injury?
• Are there alternative or complementary treatments available?
• What is the prognosis for me returning to my normal physical activities?
• Will I need physical therapy following or during treatment of my injury? If so, how long can I expect the therapy to last?

Meniscal injuries

If the tear is minor and the pain and other symptoms go away, the doctor may recommend a muscle-strengthening program. Exercises after injury to the meniscus are designed to build up the quadriceps and hamstring muscles and increase flexibility and strength. If the patient's lifestyle is limited by the knee problem, the doctor may perform arthroscopic or open surgery to see the extent of injury and to remove or repair the tear.

Ligament injuries

To reduce inflammation and pain, doctors often recommend taking an over-the-counter (OTC) nonsteroidal anti-inflammatory drug (NSAID) or aspirin. Although not an NSAID, another commonly used OTC medication, acetaminophen (Tylenol), may relieve pain. It has no effect on inflammation, however. For more severe pain and inflammation, doctors may prescribe one of several dozen NSAIDs available in prescription strength. For an incomplete tear, the doctor may recommend an exercise program to strengthen surrounding muscles. The doctor may also prescribe a brace to protect the knee during activity. For a completely torn anterior cruciate ligament, the doctor is likely to recommend surgery.

Tendon injuries

Initially, the treatment for tendinitis involves rest, elevating the knee, applying ice, and taking NSAID medications such as aspirin or ibuprofen to relieve pain and decrease inflammation and swelling. A series of rehabilitation exercises is also useful. If the quadriceps or patellar tendon is completely ruptured, a surgeon will reattach the ends. After surgery, a cast is worn for 3–6 weeks and crutches are used. For a partial tear, the doctor might apply a cast without performing surgery.

KEY TERMS

Arthroscopic surgery —Surgery of the inside of a joint of the body using an endoscope, a medical instrument consisting of a long, very thin tube inserted into the body.

Cartilage —A tough, elastic material that covers the ends of the bones where they meet to form a joint, such as the knee.

Computerized axial tomography (CAT) scan —A procedure in which x rays are passed through the knee at different angles, detected by a scanner, and analyzed by a computer. CAT scan images show soft tissues such as ligaments or muscles more clearly than conventional x rays.

Magnetic resonance imaging (MRI) —An imaging technique that uses electromagnetic radiation to obtain images of the body's soft tissues, such as the muscles and tendons.

Meniscus —Connective tissue that separates the bones of the knee.

Orthopedic —Relating to disorders of the bones, joints, ligaments, tendons, or muscles.

Osteoarthritis —A form of arthritis characterized by gradual loss of cartilage of the joints that is more common as people age.

Patella —The knee cap.

Patellar tendon —A tendon in the knee.

Quadriceps —A large group of muscles at the front of the thighs.

Tendon —The flexible but strong connective tissue that attaches muscles to bones.

Tendonitis —Inflammation of a tendon usually occurring after excessive use, as in a sports injury or repetitive movement.

Tibia —The shin bone.

Nutrition/Dietetic concerns

There are no specific nutrition or dietary concerns associated with knee injuries. However, older adults should make sure they have a sufficient intake of calcium and vitamin D (through exposure to sun-light), which helps strengthen bones and makes them less susceptible to injury.

Therapy

A key part of therapy for knee injuries is a graduated exercise program designed to return the knee to a normal level of function. With most injuries, early mobilization—getting the part moving as soon as possible—will speed healing. Generally, early mobilization starts with gentle range-of-motion exercises and then moves on to stretching and strengthening exercise when they can be done without increasing pain. Once the range of motion is fairly good, the injured person can start doing gentle stretching and strengthening exercises. In time, weights may be added to the exercise routine to further strengthen the knee. The key is to avoid movement that causes pain.

Prognosis

Prognosis depends on the type and severity of the injury, the general health of the older adult, and their age. Generally, the older a person is, the more time is required for knee injuries to heal. For most minor knee injuries, the prognosis is fairly good that the injury will completely heal. For more severe injuries, especially those that require hospitalization or surgery, the prognosis is mixed. Most people can eventually return to normal activity if proper care is taken in treating the injury and going through a rehabilitation process. In some cases, especially in people age 75 and older, it may not be possible to return to a normal full range of motion, or to do certain activities that require use of the knee, or they may have to do them at a reduced level.

Prevention

Some knee problems, such as those resulting from an accident, cannot be foreseen or prevented. However, a person can prevent many knee problems by following these suggestions:

• Before exercising or doing physical activity, warm up by walking or riding a stationary bicycle, then do stretches. Stretching the muscles in the front of the thigh (quadriceps) and back of the thigh (hamstrings) reduces tension on the tendons and relieves pressure on the knee during activity.
• Strengthen the leg muscles by doing specific exercises, such as walking up stairs or hills, or by using a stair-climbing machine. A supervised workout with weights is another way to strengthen the leg muscles that support the knee.
• Wear shoes that both fit properly and are in good condition. This will help maintain balance and leg alignment when walking or running.
• Maintain a healthy weight to reduce stress on the knee. Obesity increases the risk of osteoarthritis of the knee.

Caregiver concerns

Many factors contribute to knee injuries as the body grows older. The main one is that adults may not be as agile and resilient as they were when they were younger. It is also possible that some injuries occur when a person tries to move from inactive to a more active lifestyle too quickly. Care givers should carefully monitor their patient's participation in physical activities. They should know what their patient's limits are and make sure the limits are not exceeded. They should also be prepared to help their patient with a physical therapy or rehabilitation program should that person be injured.

Resources

BOOKS

Blaine, Sandy. Yoga for Healthy Knees: What You Need to Know for Pain Prevention and Rehabilitation Berkeley, CA: Rodmell Press, 2005.

Jensen, Jack. The One Stop Knee Shop Charleston, SC: BookSurge Publishing, 2007.

Klapper, Robert L. You're your Knees: How to Prevent Knee Surgery and What to Do If You Need It New York: M. Evans and Co., 2007.

PERIODICALS

Itoh, Kazunori, et al. “A Pilot Study on Using Acupuncture and Transcutaneous Electrical Nerve Stimulation (TENS) To Treat Knee Osteoarthritis.” Chinese Medicine (February 29, 2008): 2.

McNamara, Sophie. “Vigorous Exercise Protects Knee Joints.” Australian Doctor(October 5, 2007): 6.

Pecci, Matthew. “Knee Pain in the Recreational Athlete.” Family Practice Recertification(November 2007): 44(7).

Schipper, David. “Neutralize Knee Pain.” Men's Health (November 2007): 46.

Wood, Laurence, et al. “Associations Between Physical Examination and Self-Reported Physical Function in Older Community-Dwelling Adults With Knee Pain.” Physical Therapy (January 2008): 33(10).

ORGANIZATIONS

American Academy of Orthopaedic Surgeons, 6300 North River Road, Rosemont, IL, 60018-4262, (847) 823 7186, (800) 824-2663, (847) 823-8125, pemr@aaos.org, http://www.aaos.org.

American Physical Therapy Association, 1111 N. Fairfax St., Alexandria, VA, 22314-1488, (703) 684-2782, (800) 999-2782, (703) 684-7343, consumer@apta.org, http://www.apta.org.

Canadian Institute of Musculoskeletal Health and Arthritis, 160 Elgin St., 9th Floor, #4809A, Ottawa, ON, Canada, K1A 0W9, (613) 957-8678, imha@cihr-irsc.gc.ca, http://www.cihr-irsc.gc.ca.

National Institute of Arthritis and Musculoskeletal and Skin Diseases, 1 AMS Circle, Bethesda, MD, 20892 3675, (301) 495-4484, (877) 226-4267, (301) 718-6366, niamsinfo@mail.nih.gov, http://www.niams.nih.gov.

Ken R. Wells