Source: Buys LM, Elliott ME. Osteoarthritis.
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Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7997482.
Accessed June 22, 2012.
- Degenerative joint disease
- Progressive joint disorder caused by gradual loss of cartilage,
resulting in development of osteophytes and cysts at joint margins.
- Primary (idiopathic) osteoarthritis (OA) has no known
- Secondary OA may be associated with:
- Metabolic or endocrine disorders
- Congenital factors
- Damage to articular cartilage increases metabolic activity
of chondrocytes resulting in cartilage swelling, destruction, and
- Aggrecan destruction increases activity of matrix metalloproteinase
(MMP) 13, which destroys collagen.
- Subchondral bone releases vasoactive peptides and MMPs. Neovascularization
and increased permeability of adjacent cartilage contribute to further
- Joint space narrowing leads to painful, deformed joints.
- Remaining cartilage softens and develops fibrillations, splitting,
and exposure of underlying bone.
- Brittle, stiffer bone develops sclerosis and microfractures
and has decreased weight-bearing ability.
- New bone formations (osteophytes) appear at joint margins.
- Inflammation in joint capsule and synovium result in effusions
and synovial thickening.
- Prevalence and severity increase with age.
- 15% of Americans affected, including 50% of
those over age 65 and 85% of those age 75 or older.
- Before age 50, men are more likely to have OA than women.
- In older age groups, women have a higher prevalence of hip,
knee, and hand OA than men.
- Advancing age
- Repetitive use through work or leisure activities
- History of joint trauma
- Genetic predisposition
- Depends on duration and severity of disease and number
of joints affected.
- Localized deep, aching joint pain; limitation of motion,
stiffness, crepitus, and deformities.
- Upon arising, joint stiffness lasts <30 minutes and resolves
- Joints most commonly affected:
- Distal interphalangeal
(DIP) joints (Heberden’s nodes) and proximal interphalangeal
(PIP) joints (Bouchard’s nodes) of hands
- First carpometacarpal joints of wrist
- Cervical and lumbar spine
- First metatarsophalangeal joint of toes
- Patients with lower extremity involvement may report weakness
- Physical examination reveals tenderness, crepitus, and possibly
joint enlargement; presence of warm, red, tender joints suggests
Means of Confirmation
- Patient history, examination of affected joint(s), radiologic
findings, and laboratory testing.
- Criteria for classification of OA of hips, knees, and hands
- Presence of pain
- Bony changes on examination
- Normal erythrocyte sedimentation rate (ESR)
- Radiographs showing characteristic osteophytes or joint space
- No specific clinical laboratory abnormalities
- ESR may be elevated during inflammation.
- Rheumatoid factor negative.
- Synovial fluid analysis reveals high viscosity and mild leukocytosis
(<2000 white blood cells/mm3 [<2
× 109/L]) with predominantly mononuclear
- Changes often absent in early,
- With progression, potential joint space narrowing, subchrondral
bone sclerosis, and marginal osteophytes.
- In late OA, potential abnormal joint alignment and effusions.