22 - Osteoarthritis Flashcards
1
Q
Definition of OA
A
- ACR (American College of Rheumatology) -> joint pain that occurs for most days of the prior month plus radiographic changes in the symptomatic joint
- Impacts any joint, but typically in spine (cervical or lumbar), hands, hips, and knees
2
Q
Difference between primary and secondary OA
A
- Primary OA = idiopathic (often in the elderly)
- Secondary OA:
- Joint insults (trauma, infection)
- RA, gout
- Congenital joint abnormalities
- Hematological genetic abnormalities (leukemia)
3
Q
What protects the joint?
A
- Synovial fluid -> reduces friction between articulating cartilage surfaces (physical protectant)
- Ligaments & tendons -> via mechanoreceptor sensory afferent nerves fire during movement; allows for the right tension in joints for maximal protection
- Bone -> shock-absorbing effects
- Cartilage:
- 2-3 mm thin coating of tissue at the ends of 2 opposing bones
- Lubricated by synovial fluid to create frictionless surface for the opposing bones
- Compressible characteristics yields impact-absorbing quality
4
Q
Pathophysiology of OA
A
- Involves a complex interaction of many extracellular and intracellular molecules (metalloproteinases (MMPs), cytokines (IL-1, TNF-alpha), and growth factors)
- Cartilage destruction occurs faster than cartilage formation
- IL-1 and metalloproteases have been found to play an important role in cartilage destruction
- Local growth factors, especially transforming growth factor (TGF) are involved in formation of osteophytes
- Osteophyte = compensatory mechanism of new bone formation to stabilize the joint
- Characterized by joint pain, loss of motion, weakness, disability
5
Q
Risk factors for OA
A
- Ethnicity, age
- Gender and hormonal status
- Bone density, joint injury, joint biomechanics
- Nutritional factors
- Obesity (most modifiable risk factor), occupation
- Physical activity
- Muscle weakness
6
Q
Sx of OA
A
- Stiffness – morning or after periods of inactivity; lasts less than 30 mins
- Sx localized to affected joint
- Pain worse w/ activity (especially weight bearing) or prolonged use
7
Q
Signs of OA
A
- Often unilateral, occasionally symmetrical
- Joints not usually tender or inflamed
- Joint instability may be present
- No systemic sx
8
Q
What causes the pain of OA?
A
- Not related to destruction of cartilage
- From activation of nociceptive nerve endings within the joint by mechanical and chemical irritants
- May be due to distention of synovial capsule by increased joint fluid, microfracture, periosteal irritation, or damage to ligaments, synovium, or the meniscus
9
Q
Diagnosis of OA
A
- Clinical diagnosis = no further tests if -> > 45 y/o + activity-related joint pain + no morning joint-related stiffness or morning stiffness lasting < 30 mins
- Lab tests useful to rule out other causes of the sx
- Radiographs and joint aspiration (useful for red, hot, swollen joints)
10
Q
Physical exam of OA
A
- Pain, stiffness, and limitation of both passive and active movement of the joint
- Crepitus (grating, popping of joints), deformity, muscle atrophy, ligament tenderness in 1 or more of the affected joints
- Ligament and capsular laxity (looseness) + muscle atrophy = joint instability (later leading to deformity)
11
Q
X-ray for OA
A
- Imaging may not directly correlate w/ the clinical picture
- 2017 EULAR recommendations -> X-rays not needed for initial usual presentation of OA or follow-up
- Can help identify narrowing of joint space (due to loss of cartilage), osteophytes, and bone cysts
12
Q
Assessment of severity of OA
A
- No lab monitoring
- Assessment scales:
- Western Ontario and McMaster Universities (WOMAC) questionnaire has been widely used to assess pain, stiffness, and physical function in px w/ hip and/or knee OA
- Visual analog scale (VAS)
13
Q
Goals of therapy for OA
A
- *Relieve or eliminate pain (and stiffness)
- Improve or restore joint function and mobility
- Improve muscle strength to protect cartilage, ligaments, and joint capsule
- Prevent and reduce damage to the joint cartilage, bone, ligaments, muscles, and nerves
- Maximize QOL
- Educate the pt/caregiver to promote adherence
14
Q
Stepwise approach to OA tx
A
- Step 1 -> non-pharm (education, exercise, physiotherapy, assistive devices); acetaminophen
- Step 2 -> add topical diclofenac; advise on other topical therapies
- Step 3 -> assess risk of adverse GI events
- Low (no risk factors) = low dose nonselective NSAIDs
- Moderate (1-2 risk factors) = low dose nonselective NSAID + gastroprotection OR low dose COX-2 inhibitor
- High (multiple risk factors) = alternative therapy (ex: local injections, duloxetine, opioids) OR low dose COX-2 inhibitor + gastroprotection
- Step 4 -> if not adequate pain relief, full-dose nonselective NSAID or COX-2 inhibitor +/- gastroprotection
15
Q
Non pharms for hand OA based on ACR 2012 guidelines
A
- Evaluate ability to perform activities of daily living (ADLs) and provide assist devices
- Instruct in joint protection techniques
- Instruct in use of thermal modalities
- Provide splints for px w/ trapeziometacarpal joint OA