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Osteoarthritis

Last updated: January 25, 2021

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Osteoarthritis (OA) is a disabling joint disease characterized by a noninflammatory degeneration of the joint complex (articular cartilage, subchondral bone, and synovium) that occurs with old age or from overuse. It mainly affects the weight-bearing and high-use joints, such as the hip, knee, hands, and vertebrae. Despite the widespread view that OA is a condition caused exclusively by degenerative “wear and tear” of the joints, newer research indicates a significant heterogeneity of causation, including pre-existing peculiarities of joint anatomy, genetics, local inflammation, mechanical forces, and biochemical processes that are affected by proinflammatory mediators and proteases. Major risk factors include advanced age, obesity, previous injuries, and asymmetrically stressed joints. In early-stage osteoarthritis, patients may complain of reduced range of motion, joint stiffness, and pain that is aggravated with heavy use. As the disease advances, nagging pain may also occur during the night or at rest. Diagnosis is predominantly based on clinical and radiological findings. Classic radiographic features of OA do not necessarily correlate with clinical symptoms and appearance. If lifestyle changes (moderate exercise, weight loss) and physical therapy fail to improve symptoms, analgesics are used for the management of active osteoarthritis. If medical interventions fail to improve the patient's quality of life, surgical procedures such as joint replacement may become necessary.

See “Osteoarthritis of the hip and knee.”

Epidemiological data refers to the US, unless otherwise specified.

Osteoarthritis can be classified according to the underlying cause: [2]

Chronic mechanical stress on the joints and age-related decrease in proteoglycans cartilage loses elasticity and becomes friable → degeneration and inflammation of cartilage ; joint space narrowing and thickening and sclerosis of the subchondral bone [3][4]

In contrast to osteoarthritis, rheumatoid arthritis does not affect the DIP joints.

Osteoarthritis is usually diagnosed on the basis of clinical features. Radiographic evidence of joint degeneration supports the diagnosis of OA. [1]

Radiological signs of osteoarthritis [1]

  • Irregular joint space narrowing
  • Subchondral sclerosis: dense area of bone (visible on x-ray) just below the cartilage zone of a joint, formed due to a compressive load on the joint
  • Osteophytes (bone spurs); : bony projections that develop on joint surfaces as spurs or densifications; Osteophytes develop on the edges of the joint and thereby increase the joint surface
  • Subchondral cyst: fluid-filled cyst that develops at the surface of a joint due to local bone necrosis induced by the joint stress of osteoarthritis

The patient's history and clinical diagnosis are essential for the assessment and treatment of osteoarthritis. Radiographic signs often do not correlate with the patient's perception and clinical findings.

Other tests

See “Differential diagnoses of inflammatory arthritis.”

The differential diagnoses listed here are not exhaustive.

Pharmacotherapy should be used as acute and symptomatic therapy only; long-term NSAID therapy should be avoided due to its many side effects.

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  2. Altman R, Asch E, Bloch D, et al. Development of criteria for the classification and reporting of osteoarthritis: Classification of osteoarthritis of the knee. Arthritis & Rheumatism. 1986; 29 (8): p.1039-1049. doi: 10.1002/art.1780290816 . | Open in Read by QxMD
  3. Liu-Bryan R, Terkeltaub R. Emerging regulators of the inflammatory process in osteoarthritis. Nat Rev Rheumatol. 2014 . doi: 10.1038/nrrheum.2014.162 . | Open in Read by QxMD
  4. Lane NE, Brandt K, Hawker G et al . OARSI-FDA initiative: defining the disease state of osteoarthritis. Osteoarthritis Cartilage. 2011 . doi: 10.1016/j.joca.2010.09.013 . | Open in Read by QxMD
  5. Treatment of Osteoarthritis of the Knee, 2nd edition - Summary of Recommendations.
  6. Hochberg MC, Altman RD, April KT, et al. American College of Rheumatology 2012 recommendations for the use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip, and knee. Arthritis Care Res. 2012; 64 (4): p.465-474. doi: 10.1002/acr.21596 . | Open in Read by QxMD
  7. Ayhan E, Kesmezacar H, Akgun I. Intraarticular injections (corticosteroid, hyaluronic acid, platelet rich plasma) for the knee osteoarthritis. World J Orthop. 2014; 5 (3): p.315-361. doi: 10.5312/wjo.v5.i3.351 . | Open in Read by QxMD