Components of the knee
The knee is composed of skin covering the ligaments, tendons, muscles, bones, articular cartilage, bursa sacs, blood vessels and nerves that form the largest joint in the body. The knee joint is complex and each component is important to its function and each can suffer injury or disease. Consequently, there are many causes of knee pain. Women are twice as likely to experience knee pain as man; about 50% of all athletes have knee pain every year.
Knee pain causes
Acute injuries to one or more of the components of the knee are the leading cause of knee pain. Injuries range from mild (sprains, strains) to more serious tears (in ligaments or cartilage) and kneecap dislocations, to fractures in the bones that comprise the knee joint to a total knee joint dislocation, a medical emergency. Another kind of injury that is usually not acute is overuse or stress injuries due to repeated activities that cause joint components to become inflamed over time (for example, tendonitis or bursitis from running).
Unfortunately, there are other body problems that can cause knee pain to occur in people. Hip and back pain may cause abnormal gait which subsequently causes knee pain. Diseases such as arthritis, rheumatoid arthritis, gout, osteoarthritis, and lupus may cause knee pain. Infection of the joint, the surrounding skin (cellulitis), the bones (osteomyelitis), or bursa sac (septic bursitis) can cause knee pain. A Baker's cyst (popliteal cyst) can cause knee pain and any compromise of the nerves or vasculature can, too. Less frequent causes of knee pain can be Osgood-Schlatter disease (pain in the kneecap or tibia in children, mainly boys, ages 10 to 15) and osteochondritis dissecans (when blood flow to bone or cartilage is cut off and tissue dies).
Knee pain resolution
Resolution of knee pain, or at least a reduction in pain symptoms, depends on two things, an accurate diagnosis of the underlying cause and then the treatment of the underlying cause. With some acute injuries, accomplishment of these two steps is usually straightforward but many other causes, even some acute causes (partial ligament tears in the knee ligaments of an athlete), the diagnosis methods may require specialized tests such as MRIs or even a series of different medications (for example, in the case of knee pain with gout). Unless your knee pain is minor and rapidly improves over a day or two, you may want to consult a medical professional to help you diagnose the cause(s) of your knee pain. Patients with chronic knee pain are best served by seeing a specialist who treats joint problems (orthopedists and/or rheumatologists); your primary care doctor may refer you to an appropriate specialist.
Medically reviewed by Aimee V. HachigianGould, MD; American Board of Orthopaedic Surgery
"Knee Problems and Injuries - Topic Overview." WebMD.