As a weight-bearing joint, the knee is prone to acute and chronic injury. This hinge joint endures significant wear-and-tear with the physical activities of work and play. Diseases that cause knee pain may involve the bones, cartilage and supporting structures of the knee. Age, activities, body weight and physical conditioning influence the relative risk for the development of knee disorders.
Osteoarthritis
Osteoarthritis of the knee occurs when the cushion of cartilage the separates the leg bones deteriorates. As the cartilage thins, it becomes increasingly misshapen. The ends of the leg bones thicken, and progressive deformity of the knee joint results. Pain, joint stiffness and swelling, and limited range of movement characterize knee osteoarthritis. In a 2008 study published in "Arthritis Care & Research," Dr. Louise Murphy and colleagues reported that the lifetime risk of developing symptomatic knee osteoarthritis is approximately 45 percent, overall, and 57 percent among those with a previous knee injury. Murphy and colleagues noted that the risk of knee osteoarthritis increases with advancing age and obesity. The American Academy of Orthopaedic Surgeons states that approximately 9 million Americans were living with knee osteoarthritis as of 2005.
Chondromalacia Patella
Chondromalacia patella describes a condition wherein the cartilage behind the kneecap--the patella--softens and deteriorates. Information provided by the University of Maryland Medical Center notes that chondromalacia patella among young adults typically reflects an overuse injury. Among older adults, the disorder may occur in conjunction with arthritis. A previous injury of the kneecap increases the risk for chondromalacia patella. Symptoms commonly include pain over the front of the knee and a grating sensation felt under the kneecap. Knee pain typically worsens with prolonged sitting with the knee bent. Stair climbing provokes knee pain. Rest, anti-inflammatory medications and physical therapy remain the cornerstones of treatment. Uncommonly, surgical correction of the placement of the kneecap is required.
Pes Anserine Bursitis
A bursa is a fluid filled sac that cushions and prevents friction between two structures of the musculoskeletal system. The pes anserine bursa--located on the inner aspect of the leg just below the hinge area of the knee--acts as a cushion between the large lower leg bone and the three hamstring tendons that course over it. "Pes anserine" is a Latin term meaning goose's foot, a description of the appearance of the insertion of the three hamstring tendons on the lower leg bone. Overuse of the knee or injury in this region can cause inflammation, termed pes anserine bursitis. The American Academy of Orthopaedic Surgeons notes that obesity and preexisting knee osteoarthritis increase the risk for pes anserine bursitis. Knee pain and tenderness occur. Exercise typically aggravates the pain; stair climbing proves particularly painful. Treatment of pes anserine bursitis usually involves rest, anti-inflammatory medications and physical therapy.
References
- "Arthritis Care & Research"; Lifetime Risk of Symptomatic Knee Osteoarthritis; Louise Murphy, Ph.D., et al.; September 2008
- American Academy of Orthopaedic Surgeons: Frequently Asked Questions about Osteoarthritis of the Knee
- American Academy of Orthopaedic Surgeons: Knee Osteoarthritis Statistics
- University of Maryland Medical Center: Chondromalacia Patella
- Medline Plus: Chondromalacia Patella
