There are several causes for arthritis in the knee. Osteoarthritis is the primary cause of knee arthritis and results from wearing down the smooth articular cartilage covering the ends of the bones (thigh bone, shin bone and kneecap). Loss of cartilage results in pain, stiffness, decreased function, swelling, joint deformity and eventual immobility. Osteoarthritis can eventually progress to bone-on-bone contact, which results in further increasing pain and stiffness in the knee joint. This bone-on-bone contact induces the formation of bone spurs (osteophytes) that will also contribute to the pain and reduce mobility.
Arthritis can also develop after prior trauma to the knee, which is known as post-traumatic arthritis. Prior trauma can include a fracture in or around the knee joint, a prior ligament injury (ACL or multi-ligament knee injury), or other cartilage or meniscus injury. Even after trauma, the development of arthritis usually takes years or decades to develop.
Inflammatory arthritis is another form of knee arthritis that can lead to degeneration of the joint. It is an inflammatory disease of the synovium (the specialized membrane lining the inside of the joint), and it also causes pain and decreased range of motion. Inflammatory arthritis is a systemic disease and comes in many forms, including rheumatoid arthritis, lupus, and psoriatic arthritis, among many others.
Early stages of arthritis can be treated with rest, activity modification, weight loss, anti-inflammatory medications, bracing, and injections. Several injections are available, including steroid injections, lubricant injections (“gel” or “rooster shot”), and biologic injections (PRP or BMAC). Steroid injections are recommended as the first-line treatment, while the other options may be recommended based on a variety of patient and radiographic factors, and these options should be discussed with your doctor. When these non-surgical treatments fail to alleviate symptoms, a total knee arthroplasty (joint replacement) is the most reliable, effective and long-term treatment for arthritis of the knee.