Most people have had a minor knee problem at one
time or another. Most of the time our body movements do not cause problems, but
it's not surprising that symptoms develop from everyday wear and tear, overuse,
or injury. Knee problems and injuries most often occur during sports or
recreational activities, work-related tasks, or home projects.
knee is the largest joint in the body. The upper and lower bones of the knee
are separated by two discs (menisci). The upper leg bone (femur)
and the lower leg bones (tibia and fibula) are connected by
tendons, and muscles. The surface of the bones inside
the knee joint is covered by
articular cartilage, which absorbs shock and provides
a smooth, gliding surface for joint movement. See a picture of the
structures of the knee .
Although a knee problem is often caused by an
injury to one or more of these structures, it may have another cause. Some
people are more likely to develop knee problems than others. Many jobs, sports
and recreation activities, getting older, or having a disease such as
osteoporosis or arthritis increase your chances of
having problems with your knees.
Injuries are the most common
cause of knee problems. Sudden (acute) injuries may be caused by a direct blow
to the knee or from abnormal twisting, bending the knee, or falling on the
knee. Pain, bruising, or swelling may be severe and develop 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; tingle; or look
pale or blue. Acute injuries include:
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).
tears, such as the anterior cruciate ligament (ACL). The
medial collateral ligament (MCL) is the most commonly
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 commonly caused by abnormal force, such as a falling on the
knee, a severe twisting motion, severe force that bends the knee, or when the
knee forcefully hits an object.
dislocation. This type of dislocation occurs more
frequently in 13- to 18-year-old girls.
- Pieces of bone or tissue (loose bodies) from a fracture or dislocation that may get caught in the joint and
interfere with movement.
- Knee joint
dislocation. This is a rare injury that requires great
force. It is a serious injury and requires immediate medical care.
Overuse injuries occur with
repetitive activities or repeated or prolonged pressure on the knee. Activities
such as stair climbing, bicycle riding, jogging, or jumping stress joints and
other tissues and can lead to irritation and inflammation. Overuse injuries
- 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
- Thickening or folding of the knee ligaments (plica
- 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).