Knee Injuries

The knee is a joint made of connective tissue called tendons and ligaments, which hold the kneecap in place and attach the lower end of the thighbone to the upper end of the shinbone. The knee functions as both a hinge and a shock absorber. Because it supports nearly the entire weight of the body during walking, running, and jumping, the knee is vulnerable to a variety of injuries.

Common Injuries

• ACL tears or other ligament sprains
• Meniscal tear
• Cartilage injuries
• Arthritis
• PFPS
• Overuse injuries

• ACL tears or other ligament sprains Anterior cruciate ligament (ACL) or other ligament sprains can occur by twisting or by a violent blow to the knee. One or more of the knee ligaments—or soft tissues that connect the lower end of the thighbone, kneecap, and upper end of the shinbone—may be torn.
  
  A sprain can cause pain when bending or straightening the knee, swelling, or a “pop” sound or sensation.

• Meniscal tear A tear in the meniscal cartilage, or wedge-shaped shock absorbers between the bones of the knee, can occur from a sudden move or twist when there is weight on the knee. Gradual breakdown of the menisci also occurs with age.
  
  Cartilage is likely injured if the knee cannot be bent fully or if there is a popping or locking feeling when it’s bending.

• Cartilage injuries Osteochondral defects (OCDs), or cartilage injuries, are injuries that affect the tissue on that connects the lower end of the thighbone and the upper end of the shinbone. Injury can occur either as a result of trauma, such falling onto the knee on a hard surface, or as an abnormality of the growth process.
  
  Symptoms can include pain and swelling of the joint.

• Arthritis occurs when the cartilage at the ends of the thighbone and shinbone breaks down, which can gradually occur with age. Increased body weight and muscle weakness can contribute to the development of arthritis. Additionally, previous injury to the knee, such as untreated ligament injuries or meniscal tears, may cause premature wear of the cartilage and lead to arthritis.
  
  Cartilage damage is permanent and often causes joint injury and pain, because the two main bones of the leg are rubbing together. Stiffness and swelling are signs of arthritis.

• PFPS Patellofemoral Pain Syndrome is a term often used to describe pain under and around the front of the knee or kneecap. PFPS occurs when the cartilage—or soft tissue that cushions bones—behind the kneecap begins to break down; when the kneecap is pulled outside its normal position; or when the connective tissue that runs over the kneecap is inflamed.
  
  Muscle weakness or tightness, playing sports on a hard surface, and increased body weight contribute to this problem. Pain may occur when the knee is bent for long periods of time or when climbing stairs. Pain below the knee, particularly at the start and end of activity, may also be a symptom.

• Overuse injuries develop when the muscles around the knee are unable to meet the demands of activity, resulting in inflammation of the soft tissues around the knee. The inflammation continues unless activity is cut back or the muscles are strengthened. In addition, some overuse injuries worsen if muscles are inflexible
  
  Symptoms of overuse injuries include swelling and pain that intensifies and lingers with use of the knee.

Prevention
To reduce your risk for knee injury, follow these eight simple tips:

1. Warm up before vigorous exercise by walking and stretching the leg muscles.


2. After vigorous exercise, cool down by again walking and stretching the leg muscles.


3. Strengthen the muscles in the upper thigh and lower leg to give the knee more stability.


4. Gradually increase how hard you exercise from week to week. (For example, do not double the amount of exercise you do from one week to the next. Increase your workload by no more than 10 percent per workout.)


5. Properly align your knees with your feet while exercising.


6. Wear appropriate shoes with proper arch supports and cushioning for your particular activity.


7. If possible, avoid exercising on hard surfaces.


8. When cycling, make sure the seat height is correct for the length of your legs.

Treatment
Treat knee injuries with RICE therapy: rest, ice, compression, and elevation. Seek medical advice if pain persists for more than 72 hours despite this treatment. Rest the affected area, do not use or bear weight (standing, walking, etc.). Apply a cloth-covered ice pack to the affected area for no more than 20 minutes at a time, three to four times a day. Under a health care provider’s supervision, an elastic bandage to the area may help reduce swelling. The affected part should be elevated so it is 12 inches above the heart to help reduce swelling.