162 DEGENERATIVE JOINT DISEASE
Harrison’s Manual of Medicine
DEGENERATIVE JOINT DISEASE
Degenerative joint disease, or osteoarthritis (OA), is a disorder characterized by progressive deterioration and loss of articular cartilage accompanied by proliferation of new bone and soft tissue in and around involved joint.
Primary (idiopathic) OA: no underlying cause is apparent.
Secondary OA: a predisposing factor is present such as trauma, repetitive stress (occupation, sports), congenital abnormality, metabolic disorder, or other bone/joint disease.
Erosive OA: term often applied to pts who have hand DIP/PIP OA associated with synovitis and radiographic central erosions of the articular surface.
Initial changes begin in cartilage, with change in arrangement and size of collagen fibers. Proteases lead to loss of cartilage matrix. Proteoglycan synthesis initially undergoes a compensatory increase but eventually falls off, leading to full-thickness cartilage loss.
OA is the most common form of joint disease. It can affect almost any joint, but usually occurs in weight-bearing and frequently used joints such as the knee, hip, spine, and hands. The hand joints that are typically affected are the DIP, PIP, or first CMC (thumb base); MCP involvement is rare.
Use-related pain affecting one or a few joints (rest and nocturnal pain less common)
Stiffness after rest or in morning may occur but usually brief (< 30 min)
Loss of joint movement or functional limitation
Joint crepitation (“crackling”)
Chronic monarthritis or asymmetric oligo/polyarthritis
Firm or “bony” swellings of the joint margins, e.g., Heberden’s nodes (hand DIP) or Bouchard’s nodes (hand PIP)
Mild synovitis with a cool effusion can occur but is uncommon
Crepitance—audible creaking or crackling of joint on passive or active movement
Deformity, e.g., OA of knee may involve medial, lateral, or patellofemoral compartments resulting in varus or valgus deformities
Restriction of movement, e.g., limitation of internal rotation of hip
Objective neurologic abnormalities may be seen with spine involvement (may affect intervertebral disks, apophyseal joints, and paraspinal ligaments)
Routine lab work usually normal.
ESR usually normal but may be elevated in pts who have synovitis.
Rheumatoid factor, ANA studies negative.
Joint fluid is straw-colored with good viscosity; fluid WBCs <2000/µL; of value in ruling out crystal-induced arthritis or infection.
Radiographs may be normal at first but as disease progresses may show joint space narrowing, subchondral bone sclerosis, subchondral cysts, and osteophytes. Erosions are distinct from those of rheumatoid and psoriatic arthritis as they occur subchondrally along the central portion of the joint surface.
Usually established on basis of pattern of joint involvement, radiographic features, normal laboratory tests, and synovial fluid findings.
DIFFERENTIAL DIAGNOSIS Osteonecrosis, Charcot joint, rheumatoid arthritis, psoriatic arthritis, crystal-induced arthritides.
Pt education, weight reduction, appropriate use of cane and other supports, isometric exercises to strengthen muscles around affected joints.
Topical capsaicin cream may help relieve hand or knee pain.
Acetaminophen, salicylates, or NSAIDs; consider Cox-2-specific NSAIDs for those at risk of GI toxicity.
Tramadol—may be considered in pts whose symptoms are inadequately controlled with NSAIDs; as it is a synthetic opioid agonist, habituation is a potential concern.
Intraarticular glucocorticoids—may provide symptomatic relief but should be performed infrequently as cartilage breakdown may be accelerated if performed too often.
Intraarticular hyaluronin—indicated in pts who have not responded to nonpharmacologic therapy and analgesics; consider when NSAIDs contraindicated or ineffective.
Tidal irrigation—invasive modality; role in treatment remains unclear.
Glucosamine and chondroitin—proof of efficacy has not been established.
Systemic glucocorticoids have no place in the treatment of OA.
Surgery may be considered in pts with intractable pain and loss of function who are unresponsive to other measures.
For a more detailed discussion, see Brandt KD: Osteoarthritis, Chap. 321, p. 1987, in HPIM-15.