Knee osteoarthritis (OA) is the most common form of arthritis affecting the knee, often resulting from the progressive loss of articular cartilage. It predominantly affects older adults and can significantly impact mobility and quality of life (1).
Symptoms
Knee OA typically develops gradually, with symptoms worsening over time. Common symptoms include:
– Knee pain that is gradual in onset and worsens with activity
– Stiffness and swelling, particularly after periods of inactivity or rest
– Reduced range of motion, making it difficult to bend or straighten the knee
– Creaking, clicking, or grinding sensations during movement
– Weakness or a feeling that the knee may buckle (1-2)
Causes and Risk Factors
Knee OA is primarily a degenerative condition, caused by wear and tear of the cartilage that cushions the knee joint. There are two types:
– Primary osteoarthritis: Occurs without any apparent underlying cause, typically associated with aging.
– Secondary osteoarthritis: Results from an abnormal concentration of force across the joint (such as after an injury) or from abnormal cartilage (as in rheumatoid arthritis) (1-2).
Key risk factors include:
– Increasing age
– Obesity, which increases mechanical load and inflammation in the joint
– Previous knee injuries (e.g., ligament or meniscus tears)
– Repetitive stress from certain occupations or sports
– Genetic predisposition and metabolic diseases such as diabetes (1-2).
Diagnosis
Diagnosis of knee OA involves a combination of:
– Clinical history and physical examination to assess pain, stiffness, and joint function
– Imaging studies, such as X-rays, to evaluate cartilage loss, joint space narrowing, and bone changes. MRI may be used in select cases to assess soft tissue involvement (1-3).
Treatment Options
Non-Surgical Approaches
– Lifestyle modifications: Weight loss and regular low-impact exercise (such as swimming or walking) can reduce pain and improve function.
– Physical therapy: Tailored exercise programs help maintain flexibility and strengthen the muscles around the knee.
– Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) provide short-term pain relief. Other options include acetaminophen and topical agents.
– Supportive devices: Knee braces or orthotics may help in certain cases (1-3).
Surgical and Advanced Interventions
Surgery, such as total knee replacement, is considered when conservative treatments fail and symptoms significantly impair quality of life. Emerging therapies, including cartilage regeneration and gene therapy, are under investigation but are not yet standard care (1-3).
Living With Knee OA
Managing knee OA involves a combination of medical treatment, self-care, and lifestyle adjustments. Regular exercise, maintaining a healthy weight, and using assistive devices when needed can all help improve quality of life and reduce symptoms (1-3).
References
1. Hsu H, Siwiec RM. Knee Osteoarthritis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan. PMID: 29939661.
2. Jotanovic Z, Mihelic R, Sestan B, Dembic Z. Knee Osteoarthritis: A Review of Pathogenesis and State-Of-The-Art Non-Operative Therapeutic Considerations. World J Orthop. 2020 Jul 18;11(7):437-454. PMID: 32722615.
3. Katz JN, Arant KR, Loeser RF. Diagnosis and Treatment of Hip and Knee Osteoarthritis: A Review. JAMA. 2021 Feb 9;325(6):568-578. PMID: 33560326.