Knees are subjected to stresses every day, and pain in the joints often reflects the harsh treatment they're subjected to. Joint pain in the knee has many causes, some of which are easily avoidable and others that are common with aging or in active people. Knee joint damage impacts normal activities and can require surgical treatment.
Osteoarthritis
Osteoarthritis often occurs as part of the aging process, with nearly everyone experiencing osteoarthritis to some degree by age 80, according to The Merck Manuals Online Medical Library. Wear and tear over the years and the body's attempts to repair it lead to osteoarthritis. Abnormal new growth of bone, cartilage and other tissue damages the knee joint over time. The joint can no longer glide smoothly, due to new bone overgrowth and pitting and roughness in the cartilage.
A deep ache and stiffness commonly occur in the joint, although stiffness usually subsides after 30 minutes, especially if the joint is moved, notes Merck. Eventually the joint becomes deformed, making it harder to bend and move. Ligaments may stretch, making the joint unstable. Knee replacement may become necessary if pain medication, physical therapy and other modes of treatment fail to provide adequate relief.
Acute Injury
Active people or those who are accident prone often injure their knees. Twisting, falling, running too hard, jumping or cycling can all damage the tendons, ligaments or bone around the joint, causing pain. Sprains result from ligament damage, while strains result from muscle or tendon damage. Injuries can cause bleeding into the joints, which increases pain and disability, the University of Maryland Medical Center states. Tears in the ligaments and tendons may heal with time but often require surgical repair.
Inflammation or Infection
Injury to the knee joint often leads to pain and swelling from inflammation. This pain and swelling may be caused by tendinitis, or inflammation in the tendon; bursitis, or inflammation of the bursa, which are the fluid-filled sacs that cushion the knee; or infection in the joint. Anti-inflammatory medications, rest, ice and elevation help with inflammation, while infection requires antibiotic treatment, states Merck.
Autoimmune Disease
Rheumatoid arthritis, an autoimmune disease, can also damage the cartilage in knee joints, causing pain and disability that may require surgery. Rheumatoid arthritis causes pain and joint deformity at a younger age than osteoarthritis, according to The Ohio State University Medical Center. Other autoimmune disorders, such as systemic lupus, can also cause knee joint damage and pain.
