OA

Question 1

risk factors for OA

Answer 1

1) genetic predisposition
2) Age

• increase w age cuz wear and tear
• thinning of ECM, decreased hydration, increased brittleness of cartilage

3) anatomic factors

• varus alignment: bow-legged (knees out like penguin)
• valgus alignment: knocked-knee (knees in like need pee)

4) joint injury, mechanical stress
5) obesity

• increased load on weight bearing joints

6) gender

• < 50 yo: men > women
• > 70 yo: women > men

7) occupation
8) inflammation (IL-1, IL-6, TNF)

Question 2

pathophysiology for OA

Answer 2

• damage -> cartilage damage -> continue getting damaged
• DAMPS produced during damage -> activate immune system macrophage and pro-inflammatory cytokines -> Stimulate recruitment of other cells that stimulate complement pathway to induce inflammation
• chondrocytes activated around synovium and signals inflammation to occur -> MMPs produced -> oxidative stress

Question 3

clinical presentation of OA - number of joints

Answer 3

asymmetrical polyarthritis

Question 4

clinical presentation of OA - location

Answer 4

weight bearing joints

• knees, hip, cervical
• fingers: DIP (First part closest to fingernails), CMC (closer to base of wrist)

Question 5

clinical presentation of OA - pain characteristics

Answer 5

1) insidious
2) worse w joint use, relieved by rest
3) worse in afternoon/early evening (night pain for severe disease)
4) knees worse going down stairs/slope as compared to going up

Question 6

clinical presentation of OA - associated symptoms

Answer 6

1) inflammation
2) early morning stiffness < 30 mins, resolve w motion and recur w rest
3) crepticus on motion (popping, cracking, grating sound)
4) symptoms related to weather
5) functional limitation/instability
6) anxiety, depression, sleep disturbances

Question 7

clinical presentation of OA - deformities

Answer 7

enlarged joints

Question 8

stages of OA

Answer 8

1) stage 1

• predictable sharp pain w mechanical insult
• limit high impact activities and modest effect on function

2) Stage 2

• pain become more constant w unpredictable episodes of stiffness
• daily activities affected

3) Stage 3

• constant dull/aching pain punctuated by episodes of often unpredictable intense, exhausting pain
• severe limitations in function

Question 9

diagnostics for OA

Answer 9

1) history taking
2) physical examination
3) radiographic finding
4) lab finding

• ESR normal < 20 mm/h, significant inflammation > 20mm/h

Question 10

radiographic finding for OA

Answer 10

1) indication

• younger individuals
• presence of atypical symptoms that suggest other diagnosis
  ** recent trauma, rapidly worsening symptoms
  ** concern of infection/malignancy: unusual site, marked pain at rest, unintended weight loss

2) who dont need?

• ≥ 45 yo
• activity related joint pain in ≥ 1 joints
• morning stiffness < 30 mins

3) what is tested?

• joint space narrowing
• marginal osteophytes
• subchondral bone sclerosis
• abnormal alignment of joint

Question 11

when need urgent referral for OA

Answer 11

1) infection: septic arthritis, osteomyelitis
2) trauma: Fracture, dislocation, ligamentous injury, patella problem
3) malignancy-related causes: tumours

Question 12

non pharmaco for OA

Answer 12

1st line

1) Exercise

• reduce pain, improve physical function, increase support and stability
• low impact strengthening exercises (Swim, walk)
• neuromuscular training
• low impact aerobics or aquatic aerobics

2) Refer to physio
3) weight management

• reduce load on weight bearing joints and adipokines related inflammation

4) information and support

Question 13

surgical treatment for OA

Answer 13

total joint arthroplasty (Replacement)

• indication
  ** QoL substantially affected
  ** non-surgical treatment not effective/suitable
• post-operative rehab required for successful outcome
• CI: active infection, chronic lower extremity ischaemia

Question 14

1st line treatment for OA

Answer 14

1) knee: topical NSAID
2) hip: PO NSAID or celecoxib

Question 15

individual doses for hip OA 1st line

Answer 15

1) ibuprofen

• 400mg every 4-6 hrs or 600-800 mg every 6-8 hrs
• max dose 3200mg for acute, 2400mg for chronic

2) ketoprofen

• 50mg every 6 hrs or 75mg every 8 hrs
• max dose 300mg

3) naproxen sodium

• 275-550mg every 12 hrs or 275mg every 6-8 hrs
• max dose 1375mg for acute, 1100mg for chronic, 1650mg for disease flare

4) diclofenac

• 50mg every 8-12 hrs
• max dose 150mg

4) celecoxib

• 200mg PRN
• < 400mg/day
• use if ≥ 3 risk factor for GI toxicity

Question 16

alternative therapies for OA

Answer 16

1) paracetamol

• short term pain relief when all other treatment CI/not effective
• 500mg tablet PRN, no more than 4 tablets per day

2) tramadol

• short term pain relief when all other treatment CI/not effective
• PO 25-50mg TDS, max 400mg/day

3) OTC panadeine (paracet 500mg + codeine phosphate 8mg)

• short term pain relief when all other treatment CI/not effective
• 2 tablets each time

4) intraarticular (IA) glucocorticoid injection

• short term pain relief for moderate - severe when CI/failure w NSAIDs
• CI: periarticular infection, septic arthritis, joint instability, juxtaarticular osteoporosis

5) duloxetine

• moderate - severe symptoms when other treatment CI/not effective
• SNRI SE

6) topical capsaicin

• MOA: topical administration -> initial enhanced stimulation of TRPV1-expressing cutaneous nociceptive -> painful sensation -> reduction in TPRV1-exprssing nerve ending -> pain relief
• SE: application site reaction

7) intraarticular hyaluronic acid (HA)

• replace synovial fluid in joint
• shock absorption, traumatic energy dissipation, protective coating of cartilage, lubrication, reduce pain and stiffness
• induce biosynthesis of HA and extracellular matrix

Question 17

oral supplement for OA

Answer 17

1) glucosamine inconclusive evidence, GI SE so take w food
2) Fish oil slight anti-inflam, caution fishy taste and smell
3) Vit D can help with fall prevention