Knee-joint pain can be a tremendous aggravation and, if it becomes severe enough, can substantially affect your ability to move about and may even alter your quality of life. Knee-joint pain can be caused by many factors, ranging from injury to heredity, and treatments have evolved in accordance with the type and severity of the symptoms.
Meniscus Tear
There are two structures within the knee joint that serve mainly as shock absorbers and weight distributors. These structures are called menisci. The term for one structure is meniscus.
The meniscus is composed of a substance called fibro-cartilage, which is tough and somewhat like gristle. The meniscus has limited blood supply to it, and relies mainly on joint fluid for its nutrition, with the exception of the outer one-third, which is where the richest blood supply is located.
When a meniscus is injured, it typically manifests itself in the form of a tear. Tears of the meniscus can occur in many forms and locations, as well as levels of severity. A torn meniscus can be painful and this pain is usually located directly over the joint line on the affected side of the knee. Occasionally, a tear can involve a flap of tissue that becomes stuck between the joint surfaces of the thigh bone and the shin bone, causing pain when weight bearing is attempted.
Sprains
Sprains of the knee can be more serious than the name implies. Sprains involve injury and damage to the ligaments that stabilize the knee joint. When a ligament is sprained, it is torn, either partially or fully. There are a number of levels of severity regarding sprains.
Sprains can elicit knee-joint pain because these structures typically span the joint from the femur, or thigh bone, to the tibia, or shin bone. Injuries to the ligaments can occur in any part of the ligament tissue, either in the body, or substance, of the ligaments at their attachment points to the bones.
Tendinitis
Two major tendons are responsible for assisting with leg extension, or straightening of the leg--the quadriceps tendon and the patellar tendon. These tendons, which can be thought of as one continuous tendon that spans the knee cap and connects the front thigh muscles with the top portion of the tibia, or shin bone.
Activities such as running, jumping and squatting can all be affected by repetitive or overuse activities. The tendons become inflamed and can cause significant knee pain with attempts at bending and straightening.
Arthritis
The term arthritis generally refers to any condition that alters the normal smoothness of the joint cartilage surfaces in the knee. The joint covering is made of a highly specialized material called hyaline cartilage, which acts as a cushion when bearing weight on the joint.
Joint cartilage can wear down and degenerate from a variety of causes, such as overuse, obesity and heredity. As the hyaline cartilage breaks down and wears out, underlying raw bone surfaces become exposed to the pressure and friction of weight bearing. This can cause significant pain, inflammation and swelling of the knee. In severe cases, mobility can be seriously affected.
Patello-Femoral Knee Pain
The patello-femoral compartment of a knee joint is the part of the knee where the patella, or knee cap, and the groove of the femur, come into contact with each other during the process of bending and straightening of the leg.
Patello-femoral knee pain can be caused by problems with tracking of the knee cap in the groove of the femur, in which case there can be instances of partial dislocation and eccentric forces being placed on the opposing joint surfaces, causing pain.
