Osteoarthritis (MSK) Flashcards
What is osteoarthritis?
OA is a chronic degenerative joint disorder characterised by non-inflammatory degeneration of the joint complex; prevalence increases with age
Cartilage destruction exceeds repair –> pain and disability
What are the most commonly affected joints in osteoarthritis?
Knee > hip > hands > lumbar and cervical spine
What is the aetiology of osteoarthritis?
- mechanical and biological events that destabilise the normal process of degradation and synthesis of articular cartilage chondrocytes, ECM and subchondral bone
- involves the entire joint including the articular cartilage, subchondral bone, pericapsular muscles, capsule, and synovium
- leads to loss of cartilage, sclerosis and eburnation of subchondral bone, osteophytes and subchondral cysts
What is primary osteoarthritis?
Unknown aetiology, multifactorial causes
What is secondary osteoarthritis? (6)
- developmental abnormalities (e.g. hip dysplasia)
- trauma (e.g. previous fractures)
- inflammatory (e.g. rheumatoid arthritis, gout, septic arthritis)
- metabolic (e.g. haemochromatosis, acromegaly)
- obesity
- occupational
What happens to the chondrocytes in osteoarthritis?
Low yield
- chondrocytes are responsible for maintaining a balance between destruction and production of articular cartilage
- OA = irreversible loss of articular cartilage
- altered chondrocyte activity = increased destruction –> loss of joint volume
- chondrocytes eventually weaken and undergo apoptosis –> immune response –> patchy chronic synovial inflammation
- also fibrotic thickening of joint capsules
- eventually the bone becomes exposed = rubs with neighbouring bone
What are Heberden and Bouchard nodes in osteoarthritis and why do they occur?
Due to damage/inflammation, new bone formation on edges of bone with outward growth –> osteophytes known as Heberden (DIPJs) and Bouchard (PIPJs)
Occur due to osteophyte formation
What are the clinical features of osteoarthritis?
- pain during/after exertion, relieved by rest
- sparing of MCPJs but involves PIPs and DIPs (differentiates OA from RA)
- bony deformities
- Heberden nodes at DIPs
- Bouchard nodes at PIPs
- squaring at base of thumb
- varus deformity
- malalignment (causes varum and valgum deformities)
- crepitus
- asymmetric joint involvement
What bony deformities are seen in osteoarthritis? (4)
- Heberden nodes at DIPs
- Bouchard nodes at PIPs
- squaring at base of thumb
- varus deformity
How does osteoarthritis present (history)?
- joint pain and discomfort
- usually localised to knee, hip or spine
- use-related
- pain on movement (relieved at rest) and crepitus
- worse at end of day
- background pain at rest
- morning stiffness lasting <30 mins
- difficulty with certain movements
- feelings of joint instability
- restriction walking, climbing stairs, manual tasks
- no swelling
How does osteoarthritis present on examination?
- local joint tenderness
- bony swellings along joint margins
- Heberden’s nodes - DIP
- Bouchard’s nodes - PIP
- crepitus and pain on joint movement
- joint effusion
- restriction of range of movement
- antalgic gait (avoiding pain)
What are the risk factors for osteoarthritis? (8)
- age >50 (cartilage thinning)
- females
- obesity (excessive load, metabolic disorders)
- family history/genetic disorders (mutations in cartilage building)
- previous joint injuries
- infection
- neurologic disorders
- excessive joint loading - physically demanding job/sport
What are the 1st line investigations for osteoarthritis?
- X-ray of affected joints
- serum CRP
- serum ESR (erythrocyte sedimentation rate)
What bedside examination can be done for osteoarthritis?
MSK exam
What bloods are taken for osteoarthritis?
- CRP - may be slightly raised
- ESR - normal
- RF - if RA cannot be excluded clinically
- anti-CCP - negative
What is seen on a joint XR in osteoarthritis?
LOSS
- Loss of joint space
- Osteophytes
- Subarticular/subchondral sclerosis
- Subchondral cysts
What would CRP and ESR show in osteoarthritis?
Normal
What would RF and anti-CCP show in osteoarthritis?
Negative
What are some differential diagnoses for osteoarthritis? (6)
- bursitis - local tenderness and pain
- gout/pseudogout - more acute onset, erythematous, hot and acutely tender
- rheumatoid arthritis - small joints (MCPs), morning stiffness, ESR, CRP, RF, anti-CCP
- psoriatic arthritis - DIPs, enthesitis, tenosynovitis, erosions
- avascular necrosis - risk factor (corticosteroid use), subacute onset, localised bony tenderness, MRI
- internal derangements (e.g. meniscal tears) - acute and debilitating, preceding trauma, locking, MRI
What are the diagnostic criteria for osteoarthritis? (8)
- presence of risk factors
- pain
- functional difficulties
- knee, hip, hand or spine involvement
- tenderness
- crepitus
- stiffness
- shoulder, elbow, wrist or ankle involvement
What is the first line treatment for osteoarthritis?
Paracetamol + topical NSAIDs (only for knee and hand)
What is the second line treatment for osteoarthritis?
Oral NSAIDs
Opioids
Intra-articular corticosteroids
What is the medical management for osteoarthritis?
- analgesia
- 1st line: paracetamol + topical NSAIDs
- codeine
- 2nd line: oral NSAIDs
- weak opioids
- gastro-protection: PPI if on NSAIDs
- intra-articular corticosteroid injection
What needs to be prescribed along with oral NSAIDs for osteoarthritis?
PPI
What is the supportive management for osteoarthritis?
- patient education
- lifestyle changes (weight loss, exercise)
- physiotherapy
What is the surgical management for osteoarthritis?
- joint replacement (arthroplasty) - if patient experiencing persistent pain despite multiple treatment modalities
- joint fusion (arthrodesis)
- arthroscopic irrigation
- osteophyte removal
What treatment option is left if an osteoarthritic patient is experiencing persistent pain despite multiple treatment modalities?
Arthroplasty - complete or partial replacement of the joint
What are some complications of osteoarthritis? (3 + 6)
- effusion
- NSAID-related GI bleeding/renal dysfunction
- decline in ADL (activities of daily living)
- cystic degeneration of subchondral bone
- surrounding ligaments, neuromuscular abnormalities
- pain and disability
- nerve entrapment syndromes
- falls and fractures from reduced mobility
- spinal stenosis
Describe the prognosis of osteoarthritis.
- combination of treatment can provide adequate pain control and preserve function and QOL for many patients
- however, most patients continue to have some degree of pain and functional limitation affecting their desired activities and QOL
