Musculoskeletal · Degenerative Joint Disease
The facts most likely to be tested
Osteoarthritis is characterized by asymmetric joint space narrowing, subchondral sclerosis, and osteophyte formation on plain radiographs.
Patients typically report joint pain that worsens with activity and improves with rest, accompanied by morning stiffness lasting less than 30 minutes.
Physical examination reveals bony enlargement of the distal interphalangeal (DIP) joints, known as Heberden nodes.
Involvement of the proximal interphalangeal (PIP) joints results in the formation of Bouchard nodes.
The first carpometacarpal (CMC) joint is a classic site of involvement, often presenting with thumb base pain and squaring of the joint.
First-line pharmacologic therapy for symptomatic relief is oral acetaminophen or topical nonsteroidal anti-inflammatory drugs (NSAIDs).
Weight loss and low-impact aerobic exercise are the most effective non-pharmacologic interventions to reduce joint loading and improve functional outcomes.
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A 68-year-old woman presents to the clinic complaining of chronic pain in both hands. She notes that the pain is worse after a long day of gardening and improves with rest. Physical examination reveals bony enlargement of the distal interphalangeal joints and proximal interphalangeal joints. There is no evidence of joint warmth, erythema, or systemic symptoms. Radiographs of the hands demonstrate asymmetric joint space narrowing and osteophytes.
What is the most likely diagnosis?
Osteoarthritis
The patient's presentation of activity-related joint pain, Heberden and Bouchard nodes, and classic radiographic findings of asymmetric narrowing and osteophytes is diagnostic of osteoarthritis.
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Etiology / Epidemiology
Primary OA is age-related wear and tear; secondary OA follows trauma or obesity.
Clinical Manifestations
Morning stiffness <30 minutes; Heberden nodes (DIP) and Bouchard nodes (PIP).
Diagnosis
Radiography is the gold standard; look for joint space narrowing and osteophytes.
Treatment
Acetaminophen (initial) or NSAIDs; avoid chronic systemic steroids.
Prognosis
Progressive disease; total joint arthroplasty is the definitive treatment for end-stage.
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Epidemiology & Etiology
Most common form of arthritis, primarily affecting patients >50 years. Major risk factors include obesity, repetitive joint use, and prior joint trauma. It is a non-inflammatory, degenerative process rather than an autoimmune condition.
Pertinent Anatomy
Affects weight-bearing joints (knees, hips) and the hands. Specifically targets the DIP and PIP joints, while typically sparing the MCP joints.
Pathophysiology
Progressive loss of articular cartilage leads to subchondral bone remodeling. This results in the formation of osteophytes (bone spurs) and subchondral sclerosis. The lack of cartilage cushioning causes bone-on-bone friction, resulting in pain and limited range of motion.
Clinical Manifestations
Patients report pain that worsens with activity and improves with rest. Physical exam reveals Heberden nodes at the DIP and Bouchard nodes at the PIP. Red flags include nocturnal pain, significant swelling, or systemic symptoms, which suggest inflammatory arthritis or malignancy.
Diagnosis
Radiography is the diagnostic modality of choice. Findings include joint space narrowing, osteophytes, and subchondral sclerosis. Laboratory markers like ESR and CRP are normal in primary OA.
Treatment
First-line pharmacotherapy is acetaminophen for mild cases, though NSAIDs are more effective for pain control. NSAIDs carry risks of GI bleed and renal impairment. Intra-articular corticosteroid injections provide temporary relief. Weight loss and physical therapy are essential non-pharmacologic interventions.
Prognosis
Disease is chronic and progressive. Total joint arthroplasty is indicated for patients with severe functional impairment and failed conservative management. Monitor for NSAID-induced nephrotoxicity in elderly patients.
Differential Diagnosis
Rheumatoid Arthritis: Morning stiffness >60 minutes and MCP involvement
Psoriatic Arthritis: Sausage digits and nail pitting
Gout: Acute monoarticular pain with needle-shaped, negatively birefringent crystals
Pseudogout: Rhomboid-shaped, positively birefringent calcium pyrophosphate crystals
Septic Arthritis: Fever, elevated WBC, and positive synovial fluid culture