- Clinical science
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, nonsteroidal anti-inflammatory drugs (NSAIDs) in particular, 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.
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- Most common joint disorder in the USA, affecting more than 20 million adults
- Incidence: increases with age
- Sex: ♀ > ♂, especially in patients older than 50 years
- Incidence rates in specific joints: knee > hip > hand
Epidemiological data refers to the US, unless otherwise specified.
|Modifiable risk factors|| |
|Nonmodifiable risk factors|
- OA can be generalized or nodal
- No identifiable, underlying cause
- Genetic factors of causation have been implicated, but not definitively proven.
- Secondary OA
- Early clinical findings
- Late clinical findings
- Heberden's nodes: Pain and nodular thickening on the dorsal sides of the distal interphalangeal joints (DIP), ♀ > ♂
- Bouchard's nodes: Pain and nodular thickening on the dorsal sides of the proximal interphalangeal joints (PIP), ♀ > ♂.
- Rhizarthrosis: Osteoarthritis of the first carpometacarpal joint (between the trapezoid and the first metacarpal bone)
- Hallux rigidus: Arthrosis of the first metatarsophalangeal joint (between the first metatarsal and the first proximal phalanx), characterized by hypertrophy of the sesamoid bones.
In contrast to osteoarthritis, rheumatoid arthritis does not affect the DIP joints.
Osteoarthritis is usually diagnosed on the basis of clinical and radiographic evidence of joint degeneration.
- Irregular joint space narrowing
- Subchondral sclerosis
- Osteophytes (also: bone spurs)
- Subchondral cysts
General radiological classification of osteoarthritis according to the Kellgren-Lawrence Grading Scale
|Grade||Conventional x-ray findings|
|Subchondral sclerosis||Joint space narrowing||Formation of osteophytes|
|II||Irregular articular surface suggested||Mild||Mild|
|III||Irregular articular surface visible||Severe||Severe|
|IV||Extensive degenerative changes to complete destruction of the articular joint. Deformation/necrosis of the joint visible.|
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!
See “Differential diagnoses” section in
The differential diagnoses listed here are not exhaustive.
- In severe courses: intraarticular glucocorticoid injections (not a long-term treatment!)
Surgical therapy: if conservative and interventional measures fail
- (joint replacement)
- In case of failure of endoprosthesis or in select OA subtypes (e.g., Heberden's OA): arthrodesis (operative ankylosis)
Pharmacotherapy should be used as acute and symptomatic therapy only; long-term NSAID therapy should be avoided due to its many side effects!