Knee Problems and Injuries

Injuries are the most common cause of knee problems. Sudden (acute) injuries may be caused by a direct blow to the knee. Or they may be caused by abnormal twisting, bending the knee, or falling on the knee. Pain, bruising, or swelling may be severe and occur within minutes of the injury. Nerves or blood vessels may be pinched or damaged during the injury. The knee or lower leg may feel numb, weak, or cold. It may tingle or look pale or blue. Acute injuries include:

• Sprains, strains, or other injuries to the ligaments and tendons that connect and support the kneecap.
• A tear in the rubbery cushions of the knee joint (meniscus).
• A torn ligament, such as the anterior cruciate ligament (ACL). The medial collateral ligament (MCL) is the most often injured ligament of the knee.
• Breaks (fracture) of the kneecap, lower portion of the femur, or upper part of the tibia or fibula. Knee fractures are most often caused by abnormal force. Examples include falling on the knee, a severe twisting motion, severe force that bends the knee, and the knee forcefully hitting an object.
• Kneecap dislocation. This type of injury occurs more often in active teens and young adults.
• Pieces of bone or tissue (loose bodies) from a fracture or dislocation. They may get caught in the joint and interfere with movement.
• Knee joint dislocation. This is a rare injury that requires great force. It's a serious injury. It requires medical care right away.

Overuse injuries occur with repetitive activities or repeated or prolonged pressure on the knee. Knees can get irritated and inflamed when you climb stairs, ride a bike, jog, or jump, putting stress on your joints and other tissues. Overuse injuries include:

• Inflammation of the small sacs of fluid that cushion and lubricate the knee (bursitis).
• Inflammation of the tendons (tendinitis) or small tears in the tendons (tendinosis).
• Thickening or folding of the knee ligaments (plica syndrome).
• Pain in the front of the knee from overuse, injury, excess weight, or problems in the kneecap (patellofemoral pain syndrome).
• Irritation and inflammation of the band of fibrous tissue that runs down the outside of the thigh (iliotibial band syndrome).

Problems not directly related to an injury or overuse may occur in or around the knee.

• Arthritis, especially osteoarthritis (degenerative joint disease). This may cause knee pain. It often occurs at the site of a previous injury.
• Osgood-Schlatter disease. This causes pain, swelling, and tenderness in the front of the knee below the kneecap.
• A popliteal (or Baker's) cyst. This causes swelling in the back of the knee.
• Infection in the skin (cellulitis), joint (infectious arthritis), bone (osteomyelitis), or bursa (septic bursitis). This can cause pain and decreased knee movement.
• A problem elsewhere in the body. Things like a pinched nerve or a problem in the hip can sometimes cause knee pain.
• Osteochondritis dissecans. This causes pain and decreased movement when a piece of bone or cartilage (or both) inside the knee joint loses blood supply and dies.

Treatment for a knee problem or injury may include first aid, rest, bracing, physical therapy, and medicine. In some cases, surgery is needed. Treatment depends on:

• The location and type of injury, and how bad it is.
• Your age, health condition, and activity level (such as work, sports, or hobbies).

• Be safe with medicines. Read and follow all instructions on the label.
  • If the doctor gave you a prescription medicine for pain, take it as prescribed.
  • If you are not taking a prescription pain medicine, ask your doctor if you can take an over-the-counter medicine.
• Rest and protect your knee. Take a break from any activity that may cause pain.
• Put ice or a cold pack on your knee for 10 to 20 minutes at a time. Put a thin cloth between the ice and your skin.
• Prop up a sore knee on a pillow when you ice it or anytime you sit or lie down for the next 3 days. Try to keep it above the level of your heart. This will help reduce swelling.
• If your knee is not swollen, you can put moist heat, a heating pad, or a warm cloth on your knee.
• If your doctor recommends an elastic bandage, sleeve, or other type of support for your knee, wear it as directed.
• Follow your doctor's instructions about how much weight you can put on your leg. Use a cane, crutches, or a walker as instructed.
• Follow your doctor's instructions about activity during your healing process. If you can do mild exercise, slowly increase your activity.
• Stay at a healthy weight. Extra weight can strain the joints, especially the knees and hips, and make the pain worse. Losing a few pounds may help.