OA Flashcards
Types (4)
- OA
- traumatic arthritis
- septic arthritis
- DOD: OCD/osseous cyst-like lesions
Arthritis definitions (3)
- progressive loss of articular cartilage, accompanied by changes in the bones an STs of the joint
- primary OA: chronic repetitive trauma: age/use is a risk factor
- secondary: due to other disease: traumatic/septic arthritis
Pathogenesis
mechanical and chemical insults –> proteoglycan depletion –> vulnerable to mechanical damage –> degradative cycle!
eventual cartilage disruption becomes irreversible and results in cartilage loss
joint capsule fibrosis –> decreased ROM
Approach (5)
- history (when last shod, previous episodes
- physical exam
- gait evaluation
- diagnostic local anaesthesia
- diagnostic imaging
Grading system of lameness
0: No lameness
1: Difficult to observe, not consistently apparent regardless of circumstances
2: Difficult to observe at the walk or trotting in straight line, consistently apparent under certain circumstances, e.g. lunging
3: Consistently observable at a trot under all circumstances
– Broken down again into mild, moderate and marked
– Most horses
4: Obvious lameness with marked nodding, hitching or shortened stride
5: Minimal weight bearing in motion and or/rest, inability to move
CS (3)
- Joint distension (may be difficult due to overlying structures/ST): may just see swelling
- reduced ROM
- positive response to flexion test
Investigation
- radiography
- MRI/arthroscopy
- bone scan (subchondral bone has increased cell turn over anyway)
Treatment (5)
- treat primary cause if secondary
- management: CEP, correct weight, improve foot conformation
- medicatate: NSAIDs
- I/A medication
- Feed supplements
I/A medication (6)
- triamcinolone acetonide
- methylprenisilone
- polysulphate proteoglycans
- hyaluronan
- pentosan polysulphate
- IRAP
Triamcinolone acetonide (3)
- DMOAD: promotes cartilage matrix production
- low dose infrequently repeated: benefit of reducing inflammation exveeds the negative effects it has on chonrdrocytes
- short acting: withdrawal 7 dyas
methylprednisilone (2)
- longer acting: withdrawal 42 days
- not DMOAD –> acts on low motion joints
polysulphate proteoglycans (3)
- DMOAD: inhibits cytokines and degradative enzymes, restores GAG content of cartilage and synovial fluid
- only I/M
- 7 injections, 4 days apart
hyluronan (2)
- for acute synovitis
- I/A, I/V, feed supplement
Pentosan polysulphate (2)
- DMOAD
- I/M
IRAP (1)
autologous conditioned serum: blood is taken using special syringe , spun down, altered and injected back in.
Feed supplements (4)
- stimulate matrix synthesis
- inhibit matrix degradation
- anti- inflammatory
- chondroitin sulphate, glucosamine, hyluronan, avocado and soya bean extracts
Bone Spavin
- what
- why
- CS (7)
- OA of distal hock joints: DIP > TMT > PIT
- due to uneven loading/ incomplete ossification
CS
- uni/bi lateral lameness
- swelling over seat of spavin
- gait abnormalities:
- -> shortened cranial phase: toe drag
- -> limb carried medially during protraction and then outward stab to land on lateral foot
- -> choppy/stilited gait
- -> positive proximal flexion test
Bone spavin
- investigation (2)
- Tx
- -> conservative (7)
- -> progressive (2)
Investigation:
- positive response to I/A anaesthesia
- radiographs: new bone at margins, ankylosis, fusion of DMT
Tx:
conservative
- CEP and NSAIDs –> promote ankylosis
- shoeing
- I/A medication (repeat at least every 3-6 months or no benefit)
-re- examine every 6-8 weeks, stopping NSAIDs 3 days before exam
-doing well: reduce NSAID dose
- little/no improvement: continue/consider alternatives
- worse: consider alternatives
progressive
- arthorodesis
- equidronate Iv infusion: reduces bone lysis and pain, targets osteoclasts
conservative
