Osteoarthritis

Background

Risk Factors

• Age
• Female versus male sex
• Obesity
• Lack of osteoporosis
• Occupation
• Previous injury
• Muscle weakness
• Genetic elements

Clinical Features

• Commonly affected joints
  • Cervical and lumbar spine
  • First carpometacarpal joint
  • Proximal interphalangeal joint
  • Distal interphalangeal joint
  • Hip
  • Knee
  • Subtalar joint
  • First metatarsophalangeal joint
• Uncommonly affected joints
  • Shoulder
  • Wrist
  • Elbow
  • Metacarpophalangeal joint

Differential Diagnosis

Monoarticular arthritis

Algorithm for Monoarticular arthralgia

• Acute osteoarthritis
• Avascular necrosis
• Crystal-induced (Gout, Pseudogout)
• Gonococcal arthritis, arthritis-dermatitis syndrome
• Nongonococcal septic arthritis
• Lyme disease
• Malignancy (metastases, osteochondroma, osteoid osteoma)
• Reactive poststreptococcal arthritis
• Trauma-induced arthritis
  • Fracture
  • Ligamentous injury
  • Overuse
• Avascular necrosis
• Decompression sickness
• Spontaneous osteonecrosis
• Hemorrhagic (e.g. hemophilia, systemic anticoagulation
• Seronegative spondyloarthropathies (ankylosing spondylitis, IBD, psoriatic arthritis, reactive arthritis
• RA, SLE
• Sarcoidosis, amyloidosis
• Periarticular pathology
  • Cellulitis
  • Tendonitis
  • Bursitis
• Transient (Toxic) Synovitis (Hip)
• Slipped Capital Femoral Epiphysis (SCFE)
• Legg Calve Perthes Disease

Polyarthritis

Algorithm for Polyarticular arthralgia

• Fibromyalgia
• Juvenile idiopathic arthritis
• Lyme disease
• Osteoarthritis
• Psoriatic arthritis
• Reactive poststreptococcal arthritis
• Rheumatoid arthritis
• Rheumatic fever
• Serum sickness
• Systemic lupus erythematosus
• Serum sickness–like reactions
• Viral arthritis

Diagnosis

• Greater than 50 years of age
• Morning stiffness for less than 30 minutes
• Crepitus on active motion of the knee
• Bony tenderness
• Bony enlargement
• No palpable warmth