Knee pain can be caused by a sudden injury, an overuse injury, or by an underlying condition, such as arthritis. Treatment will vary depending on the cause. Symptoms of knee injury can include pain, swelling, and stiffness and instability.
The knee is a joint which has three parts. The thigh bone (femur) meets the large shin bone (tibia) forming the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap (patella) joins the femur to form a third joint, called the patellofemoral joint.
The knee joint is surrounded by a joint capsule with ligaments strapping the inside and outside of the joint (collateral ligaments) as well as crossing within the joint (cruciate ligaments). These ligaments provide stability and strength to the knee joint.
The meniscus is a thickened cartilage pad between the two joints formed by the femur and tibia. The meniscus acts as a smooth surface for the joint to move on. The knee joint is surrounded by fluid-filled sacs called bursae, which serve as gliding surfaces that reduce friction of the tendons. There is a large tendon (patellar tendon) which envelopes the knee cap and attaches to the front of the tibia bone. There are large blood vessels passing through the area behind the knee (referred to as the popliteal space). The large muscles of the thigh move the knee. In the front of the thigh, the quadriceps muscles extend, or straighten, the knee joint by pulling on the patellar tendon. In the back of the thigh, the hamstring muscles flex, or bend, the knee. The knee also rotates slightly under guidance of specific muscles of the thigh.
Injury can affect any of the ligaments, bursae, or tendons surrounding the knee joint. Injury can also affect the ligaments, cartilage, menisci (plural for meniscus), and bones forming the joint. The complexity of the design of the knee joint and the fact that it is an active weight-bearing joint are factors in making the knee one of the most commonly injured joints.
Trauma can cause injury to the ligaments on the inner portion of the knee (medial collateral ligament), the outer portion of the knee (lateral collateral ligament), or within the knee (cruciate ligaments). Injuries to these areas are noticed as immediate pain, but are sometimes difficult to localize. Usually, a collateral ligament injury is felt on the inner or outer portions of the knee. A collateral ligament injury is often associated with local tenderness over the area of the ligament involved. A cruciate ligament injury is felt deep within the knee. It is sometimes noticed with a "popping" sensation with the initial trauma. A ligament injury to the knee is usually painful at rest and may be swollen and warm. The pain is usually worsened by bending the knee, putting weight on the knee, or walking. The severity of the injury can vary from mild (minor stretching or tearing of the ligament fibers, such as a low grade sprain) to severe (complete tear of the ligament fibers). Patients can have more than one area injured in a single traumatic event.
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Arthitis is associated with pain and swelling of a joint. The causes of knee joint pain and swelling range from noninflammatory types of arthritis such as osteoarthritis, which is a degeneration of the cartilage of the knee, to inflammatory types of arthritis (such as rheumatoid arthritis or gout). Treatment of the arthritis is directed according to the nature of the specific type of arthritis.
OKAPED supplies Braces from the Leaders in bracing technology. See our section on Knee Braces to see how our staff can help you reduce knee pain caused by arthritis.
Tendinitis of the knee occurs in the front of the knee below the kneecap at the patellar tendon (patellar tendinitis) . Tendinitis is an inflammation of the tendon, which is often produced by events, such as jumping, that strain the tendon. Patellar tendinitis, therefore, also has the name "jumper's knee." Tendinitis is diagnosed based on the presence of pain and tenderness localized to the tendon.
The kneecap (patella) is normally positioned over the front of the knee joint at the base of the thighbone (femur). Some common reasons that a kneecap can be dislocated, or moved out of its normal position, are:
A dislocation can cause other problems even if the bone pops back into place. If the dislocation was due to a preexisting malalignment, the knee may dislocate again.
Ligaments, tendons, muscles, and cartilage in or around the joint may stretch or tear. A piece of bone may break off somewhere in the knee joint.
OKAPED supplies Braces from the Leaders in bracing technology. See our section on Knee Braces to see how our staff can help you recover from an patella injury.