SAPHO

• Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis
• soft tissue calcification between medial clavicle, anterior upper ribs, manubrium
• HLA-B27 positive

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Erosive Arthritis

• osteoarthritis with inflammatory symptoms
• middle-aged women
• gull-wing appearance of DIP

Reactive Arthritis

• Reiter syndrome = conjunctivitis, urethritis/cervicitis, arthritis
• RF negative, 80% HLA-B27 positive
• prior Chlamydia, Salmonella, Shigella, Yersinia, Campylobacter infection
• calcaneal erosive disease and spur formation
• M>F

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Psoriatic Arthritis

• asymmetric erosion
• bone production
• normal bone density
• 5 patterns
  • oligoarthritis (sausage digit)
  • polyarthritis (DIP>PIP/MCP) = DIP fusion, periostitis
  • symmetric
  • arthritis multilans (pencil-in-cup)
  • spondyloarthropathy (biltaeral SI)

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Ankylosing Spondylitis

• HLA-B27 positive
• M>F
• adolescents
• findings
  • bilateral SI erosion –> ankylosing
  • bamboo spine
  • large central joints > small peripheral
• SI findings similar in spondylitis of inflammatory bowel (UC > Crohn’s and Whipple’s)

Charcot’s Joint

• neuropathic arthropathy
• five D’s
  • normal bone density
  • joint distension
  • bony debris
  • joint disorganization
  • dislocation
• large effusions
• Lisfranc’s dislocation in diabetic foot
• knee = tabes dorsalis, DM
• shoulder = syringomyelia
• spine = DM, iatrogenic

Juvenile Rheumatoid Arthritis

• group of diseases
  • Still’s disease
  • Pauciarticular disease (MC)
  • Seronegative polyarticular disease
  • Seropositive polyarticular disease
  • Juvenile ankylosing spondylitis
• findings
  • soft tissue swelling
  • periosteal reaction
  • early bone maturation (early ossification, overgrowth of epiphyses)
  • carpal fusion
  • c spine ankylosis and “waisting” of the bodies
  • joint contractions
• knee, elbow, hips

Rheumatoid Arthritis

• inflammatory synovial proliferation (pannus) resulting in destruction of the joint
• F>M
• extra-articular disease: bursitis, pleural or pericardial effusions, pulmonary nodules, interstitial pneumonitis
• general findings
  • polyarticular
  • symmetric
  • axial and appendicular
  • diffuse soft tissue swelling
  • periarticular osteoporosis
  • subchondral erosions/cysts
  • NO bone proliferation = good negative predictorget PA and “ballcatchers” views of the hand, AP/lat feet, and lateral c spine
• hand/wrist
  • proximal to distal
  • radioulnar and radiocarpal joints early; DIP late
  • ligament and tendon ruptures –> instability patterns
  • Swan neck, boutonniere, hitchhiker’s thumb deformities
• elbow
  • synovitis, effusion
  • distal humerus erosion, radial head/neck
• shoulder girdle
  • distal clavicle erosion
  • rotator cuff injury; superior subluxation of humeral head
• foot
  • lateral deviation of MTP
  • hammer toe
  • cock-up deformity (hyperextended MTP joints)
  • retrocalcaneal bursitis
• knee
  • joint effusion and popliteal cyst
  • tricompartamental joint space loss, erosion, subchondral cyst
  • valgus deformity
  • patellar tendon rupture
• hips
  • axial migration of femoral head –> protrusio
  • anterior hip soft tissue mass = leaked synovial effusion into iliopsoas bursa
• c spine
  • antlantoaxial subluxation > 2.5 mm
  • antlantoaxial impaction = odontoid protrudes into foramen magnum
  • odontoid erosion

Robust RA = predominantly erosive change in men

Adult Still’s Disease = fever, rash, pleuritis, pericarditis, LAD, hepatosplenomegaly

CPPD

• Calcium Pyrophosphate Dihydrate Crystal deposition
• triad: pain, chondrocalcinosis, joint destruction
• Chondrocalcinosis in medial/lateral knee compartments, triangular fibrocartilage of the wrist, and symphisis pubis are diagnositc of CPPD
• joint destruction similar to DJD
• joint aspiration can confirm
• mimicks Charcot joint (pseudo-Charcot joint)
• associated with primary hyperparathyroidism, gout, and hemochromatosis

Gout

• hyperuricemia
• deposition of monosodium urate crystals; crystal-induced arthritis
• takes 4-6 years before radiographically evident disease
• Hallmarks
  • well-defined erosision (sclerotic margins)
  • soft tissue nodules
  • random distribution
  • no osteoporosis

High Riding Shoulder joint

high riding humeral head differential includes:

• Rheumatoid Arthritis
• CPPD
• torn rotator cuff

Arthritis Differential

By Location in the Hand

• Distal: Osteoarthritis, Psoriasis, Reiter’s
• Proximal: RA, CPPD

Bilateral and Symmetric

• Osteoarthritis
• RA

Monoarticular

• septic
• trauma
• Charcot’s joint (neuropathy)
• Gout
• Lyme
• Early Polyarticular arthritis

Large Joint Involvement

• OA
• RA
• CPPD
• Akylosing Spondylitis
• Pigmented Villonodular Synovitis
• Synovial Osteochondromatosis
• Infection

SI Joint Involvement

• Ankylosing Spondylitis
• Inflammatory Bowel
• Psoriasis
• Reiter’s Syndrome
• OA
• Infection
• Gout
• Hyperparathyroidism

Normal mineralization

• OA
• CPPD
• Gout
• Pigmented Villonodular Synovitis
• Synovial Osteochondromatosis