What is Knee Osteoarthritis?
Knee osteoarthritis (OA) is a degenerative joint disease that occurs when the cartilage in the knee joint gradually wears away. Cartilage is a smooth, slippery tissue that cushions the ends of bones and helps the joint move smoothly. As it deteriorates, the bones may begin to rub against each other, leading to pain, swelling, stiffness, and reduced mobility. Knee osteoarthritis primarily affects older adults but can occur in younger individuals as well.
Causes of Knee Osteoarthritis
Common causes and risk factors of knee osteoarthritis include:
- Aging: Most common in people over 50.
- Joint injury or overuse: Repetitive stress or trauma can accelerate wear.
- Obesity: Extra weight adds stress to the knee joint.
- Genetics: Family history can increase risk.
- Other joint conditions: Such as rheumatoid arthritis or gout.
- Joint malalignment: Such as bowlegs (varus) or knock knees (valgus) can increase risk.
Signs and Symptoms of Knee Osteoarthritis
Common symptoms of knee osteoarthritis include:
- Pain: Worsens with activity and improves with rest.
- Stiffness: Especially after resting or in the morning.
- Swelling: Due to inflammation or fluid buildup.
- Limited movement: Difficulty bending or straightening the knee.
- Grinding or clicking sounds: Felt or heard during movement.
- Weakness or instability: The knee may feel like it could give out.
Diagnosis of Knee Osteoarthritis
The diagnosis of knee osteoarthritis is typically based on a combination of clinical evaluation and imaging studies. A physician will begin with a detailed medical history and physical examination, assessing symptoms such as joint pain, stiffness, swelling, and reduced mobility. During the physical exam, the doctor may check for tenderness, crepitus (a grinding sound), and joint instability. Imaging studies, especially X-rays, are commonly used to confirm the diagnosis by revealing characteristic changes like joint space narrowing, bone spurs (osteophytes), and changes in bone shape. In some cases, an MRI may be ordered to evaluate soft tissue structures such as cartilage and ligaments, particularly if the diagnosis is unclear or other joint issues are suspected. Laboratory tests may also be conducted to rule out other conditions like rheumatoid arthritis or gout.
Treatment for Knee Osteoarthritis
Treatment for knee osteoarthritis aims to reduce pain, improve joint function, and slow the progression of the disease. Non-surgical options are typically tried first and include lifestyle modifications such as weight loss and regular low-impact exercises to reduce stress on the knee. Medications like acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs) can help relieve pain and inflammation, while physical therapy focuses on strengthening the muscles around the knee and improving flexibility. In some cases, patients may benefit from corticosteroid or hyaluronic acid injections to reduce inflammation and enhance joint lubrication. Emerging therapies like platelet-rich plasma (PRP) or stem cell injections are also being explored. Supportive devices such as knee braces or orthotics can help offload pressure from the affected area. When conservative treatments are no longer effective and symptoms become severe, surgical options such as arthroscopy, osteotomy, or partial or total knee replacement may be considered to restore mobility and reduce pain.
