Osteoarthritis

Question 1

What is the epidemiology of osteoarthritis?

Answer 1

Most common joint condition

F>M at 3:1

Very common to show some radiographic features aged >60yrs but only 1/4 of these will be symptomatic

Hips (11%) + knees (24%) are some of the most common

Question 2

What are some risk factors for OA?

Answer 2

Heritability for hand knee and hip OA = c.40-60%; polygenic and genes largely unknown

Ageing, female sex, obesity

High bone density = risk factor for development
Low bone density = risk factor for progression of knee and hip OA

Joint injury 
Occupational and recreational stresses on joints 
Reduced muscle strength 
Joint laxity 
Joint malalignment

Question 3

What is the pathophysiology of OA?

Answer 3

Focal destruction of articular cartilage:

• Balance between cartilage repair and damage breaks down
• Chondrocyte proliferation > excess cartilage creation > erosion of these excesses by movement . massive, non-copensatable destruction, chondrocyte death > no matrix synthesis > roughening (fibrilation of cartilage surfaces) > no bone protection > potential bone microfracture + osteophyte formation (bony spurs forming on joint margins)

Non-inflammatory

Bone changes = variable, some have massive new bone formation, some none

Pain - from the rubbing of the condyles of bones after the protection of the cartilage has been removed

Question 4

How does OA present?

Answer 4

Joint pain:

• Provoked by movement and relieved by rest; can progress to pain at rest and at night
• Knee pain = often bilateral and felt around knee
• Hip pain = felt in groin and anteriolateral thigh; also referred to the knee (and ipsilateral testicle in males)
• Is insidious, can be over years
• Periarticular tenderness

Joint stiffness:
- Morning stiffness <1hr then returning towards the end of the day or after a period of heightened activity or prolonged immobility

Joint instability + loss of function

Muscle wasting

Crepitus (grating sensation produced by friction between bone + cartilage or bone + bone)

Synovitis:

• Possible
• Swelling, warmth
• Inflammation of synovial membrane > fluid volume increase > joint swelling (though often not pronounced) +/- nodule formation

Nodes:

• Due to osteophyte formation
• Heberden’s = DIP joints
• Bouchard’s = PIP joints
• Also hips and knees

There are no systemic signs e.g. fever, rash etc

Question 5

How do you investigate OA?

Answer 5

Diagnosis usually clinical

Bloods:

• Normal (possible very small raise in CRP)
• Check baseline FBC, creaatinine, LFTs before starting NSAIDs

BMI recorded

Joint aspiration:
- Can help if there is doubt, to exclude septic arthritis and gout etc.

X-rays

Question 6

What are the X-ray signs of OA?

Answer 6

LOSS:

• Loss of joint space
• Osteophytes
• Subarticular sclerosis (thickening)
• Subchondral bony cysts

Also:
- Chondrocalcinosis = accumulation of calcium salts within fibrous or hyaline cartilage; is radioopaque

Question 7

How do you holisitically manage osteoarthritis?

Answer 7

• ICE, existing knowledge about OA
• Support network?
• Current mood?
• Pain assessment - what drugs tried + regimens? Other treatable sources of pain?
• Sleep hygiene
• Comorbidity management
• Provide patient education
• Encourage exercise in all - to help aerobic fitness, encourage weight loss and build muscles - physio might be useful
• Thermotherapy (heat or cold) should be considered as an adjunct for core treatments
• Advice on footwear (shock absorbing properties) in lower limb OA; assistive devices e.g. walkers for specific problems with ADLs

Annual review for:

• Troublesome joint pain
• > 1 joint affected
• > 1 comorbidity
• Taking regular medications for OA

Question 8

What drug treatments are available for OA?

Answer 8

1st line:

• Paracetamol PO + topical NSAIDs
• (Topical capsaicin can be used as an adjunct)

2nd line:

• Addition of NSAIDs/highly selective COX-2 inhibitors PO
• Co-prescribed with a PPI

Intraarticular steroid injections:
- Should be considered as an adjunct to above for relief of moderate-to-severe pain in people with OA

Question 9

What are the indications for surgery?

Answer 9

Ensure person has been offered all of the non-surgical options before

Knee OA with clear history of mechanical locking

Symptomatic + significantly reduced QoL

Arthroplasty (joint replacement) is the mainstay of treatment

Can also have removal of problematic osteophytes, intraarticular washouts etc

Question 10

What are the preventative measures for OA?

Answer 10

Weight loss

Increasing physical activity

Avoiding injury

Education programmes (including patients as educators)

Optimal management of symptoms in primary care to reduce the need for secondary care involvement and increased disability

Question 11

What is the prognosis for OA?

Answer 11

Most people aren’t severely disabled

Knee = worst, most cases deteriorate over 10yrs

Hand = best