Osteoarthritis (OA) Degenerative Joint Disease (DJD)

Question 1

General Comments - OA

Most common form of arthritis worldwide

Leading cause of pain and disability of lower extremity among older patients

Risk Factors: age (>55), female, obesity, occupations (repetitive motions or physical labor), genetic mutations (protein involved in bone or articular cartilage structure), joint loading, injury – trauma, malignant, injury is linked to future development of OA

non-inflammatory arthritis without systemic symptoms

Pain relieved by rest; morning joint stiffness is brief, oligoarticular

Answer 1

Pathophysiology:

Combination of multifactorial stressors including the following: consequences of aging,

hyaline articular cartilage loss (predominately type 2 collagen and proteoglycan – aggrecan), increasing thickness and sclerosis of subchondral bone plate, outgrowth of osteophytes at the joint margin,

joint injury,

extracellular matrix degeneration.

Synovial inflammation with hypertrophy and effusion, inflammatory cytokines such as interleukin – 1B and TNF alpha that drive tissue destruction

Question 2

pathophysiology

combination of aging, hyaline articular cartilage loss (predominantly type 2 collagen and proteoglycan (aggrecan). increased thickness and sclerosis of subchondral bone plate.

outgrowth of osteophytes at joint margin

synovial inflammation and effusion of IL-1B and TNF-alpha that drive the tissue destruction

Question 3

OA Characteristics

• Altered chondrocyte function
• Loss of cartilage – thinning
• Subchondral bone thickening – sclerosis
• Remodeling of bone
• Marginal spurs – osteophytes
• Subchondral bone – Cystic changes
• Mild reactive synovitis

Answer 3

Clinical manifestations of OA

affects weight bearing joints and frequently used joints; hips, knees, spine, hands (DIP, PIP, 1st CMC – thumb base)

Usually > 50 years of age

Pain worse with activity; alleviated with rest

Morning stiffness (about 30 minutes)

Crepitus, dec ROM, effusion (cool – not hot)

Heberdens and Bouchard nodes

Hip involvement manifests as groin pain

Knee symptoms – pain on walking, climbing stairs

Spondylosis – OA of spine, can lead to spinal stenosis

Joint instability

Question 4

Common OA sites

• Cervical spine
• Lumbar spine
• 1st CMC
• PIP
• DIP
• Hip
• Knee
• 1st MTP

Answer 4

Less Common

• Shoulder
• Thoracic spine
• Elbow
• Wrist
• MCP
• Ankle
• Subtalar

Question 5

Imaging Studies - Radiographs

Asymmetric joint – space narrowing

• Subchondral sclerosis – thickening
• Osteophytes and marginal lipping
• Bone cysts
• Joint mice (loose particles)

Answer 5

Classification of OA

Primary OA most common, no identifiable cause is recognized

• Joints affected DIP (distal interphalangeal), PIP (proximal interphalangeal) of fingers
• 1st carpometacarpal joint (base of thumb)
• Hip and knee joints, cervical and lumbar spine

Question 6

Erosive OA (inflammatory)

Affects DIP and PIP joints, more pain than typical hand OA

• More common in women

• Central erosions on radiographs (marginal erosions in RA) with “seagull” appearance in finger joints

Answer 6

Secondary OA

Underlying disorder; may be observed in joint not typically involved in primary OA

• Trauma, joint infection, surgical repair (ACL or meniscectomy), congenital joints (hips dysplasia), metabolic, endocrine

Example – Hemochromatosis (Fe overload), 2nd/3rd MCP joints and wrist

Calcium pyrophosphate deposits (pseudogout) MCP, wrist, knees, hips, shoulders

• Hyperparathyroidism – wrist, MCP

Question 7

Rheumatoid arthritis

Primary joints affected: Metacarpophalangeal, Proximal interphalangeal

Heberden’s nodes: Absent

Joint characteristics: Soft, warm, and tender

Stiffness: Worse after resting (eg, morning stiffness)

Laboratory findings: Positive rheumatoid factor, Positive anti‐CCP antibody, Elevated ESR and CRP

Answer 7

Osteoarthritis

Primary joints affected: Distal interphalangeal, Carpometacarpal

Heberden’s nodes: Frequently present

Joint characteristics: Hard and bony

Stiffness: If present, worse after effort, may be described as evening stiffness

Laboratory findings: Rheumatoid factor‐negative, Anti‐CCP antibody‐negative, Normal ESR and CRP

Question 8

Differential Diagnosis

Calcium pyrophosphate deposition (Pseudogout):

– Hands/knees

– X-rays show cartilage calcification (chondrocalcinosis)

Gout can coexist with OA, particularly in DIP joint

• Psoriatic arthritis can involve DIP; causes morning stiffness, joint swelling dactylitis and history of psoriasis
• Charcot Joint
• RA
• Osteonecrosis

Answer 8

DISH (Diffuse Idiopathic Skeletal Hyperostosis)

• Non-inflammatory condition
• Calcification and ossification of spinal ligaments (anterior longitudinal ligament) and enthesis (tendon and ligament attachments to bone)
• Men, back pain, stiffness, T-spine more often involved
• No SI joint involvement
• Ossifications of at least 4 contiguous vertebral levels, usually on right side of spine

Question 9

xray

aymmetric joint-space narrowing

subchondral sclerosis-thickening

osteophytes and marginal lipping

bone cysts

joint mice (loose particles)