Types and Causes of Knee Injuries

Direct blows to the knee can cause injury, but the knee is more susceptible to twisting or stretching injuries that cause the joint  a greater range of motion than it can tolerate.

Knee stress from a specific direction can cause the ligament trying to hold it in place can tear. Ligament stretching or tears are called sprains. These sprains are graded as first, second, or third degree based upon the degree of damage.

• Grade I sprains stretch the ligament but don't tear the fibers;

• Grade II sprains partially tear the fibers, but the ligament remains intact; and

• Grade III tears completely tears the ligament.

Twisting injuries to the knee put stress on the cartilage or meniscus and can pinch it between the tibial surface and the edges of the femoral condyle, causing tears.

Injuries of the muscles and tendons surrounding the knee are caused by acute hyperflexion or hyperextension of the knee or by overuse. These injuries are called strains. Strains are graded similarly to sprains, with first-degree strains stretching muscle or tendon fibers but not tearing them, second-degree strains partially tearing the muscle tendon unit, and third-degree strains completely torn.

There often is inflammation of the bursas (known as bursitis) of the knee that can occur because of direct blows or chronic use and abuse.

Acute knee injuries fall into two groups;

•  immediate swelling in the joint with the inability to bend the knee and bear weight,

• discomfort and perhaps localized pain to one side of the knee, but with minimal swelling and minimal effects on walking.

Knee Injury Symptoms

 Acute knee injuries can cause pain and swelling including trouble bending the knee or bearing weight. Rapid swelling may suggest a ligament tear or fracture. If  swelling occurs over a period of many hours, meniscal or cartilage injuries may be the cause.

Long term knee symptoms may include pain and swelling including Inflammation in the joint caused by even minor activity such a golf, waling or otherwise seemingly minor activities.

Any instability of the knee,  popping,  or grinding in the knee is usually associated with cartilage or meniscus tears.

The swollen knee and knee pain is caused by damage to the blood vessels that supply oxygen and nutrients to soft tissue cells or muscles. The injured soft tissue cells are deprived of the oxygen and nutrients necessary for healthy cells and maintenance of the body’s natural healing process. The damaged blood vessels are also unable to remove cell waste. Uncontrolled, this process causes cell death and results in blood and fluid seeping into the damaged portions of the muscle causing swelling and bruising which creates additional injury to the affected area. This additional injury is what prolongs recovery from knee sprains and strains.