Lame - equine joint disease Flashcards
What is the presentation of asymptomatic synovitis?
Inflammation of the synovium
Effusion of the joint or sheath
No pain
No lameness
No radiological changes
What is the aetiology of asymptomatic synovitis?
Uncertain
May be conformation
May be minor trauma
Should you treat asymptomatic synovitis? How?
No - will resolve on its own
What is the name for joint flares?
Reactive synovitis
What is the presentation of reactive synovitis?
Acute onset joint flare 24 hrs after joint injection
How can you test to make sure it is a reactive synovitis and not a septic arthritis?
Synoviocentesis - should have a total nucleated cell count of <30x10^9 cells/litre
What are the clinical signs associated with a reactive synovitis?
Lameness variable
Effusion and heat
Resents palpation/flexion
When should a reactive synovitis resolve?
In 1-3 days
What is the aetiology of reactive synovitis?
Injection induces inflammation
Reaction to the chemicals in the injection - steroid induced arthropathy
Should you treat reactive synovitis? How?
Yes - oral NSAIDs
What is the usual presentation of a traumatic synovitis?
Can be any horse but usually a young horse in training
What are the clinical signs of traumatic synovitis?
Effusion
Pain on flexion
May be lame
What test should you do for a traumatic synovitis? What results will you get?
Synoviocentesis - total nucleated cell count normal (<10x10^9 cells/litre)
What is a haemarthrosis?
Blood in the synovial fluid
Whole fluid will be pink - if just a string of red then probably iatrogenic
What is the aetiology of traumatic synovitis?
Trauma - single or repeated
May be more trauma to the surrounding area too eg. cartilage damage, ligament injury
What are the consequences of traumatic synovitis?
May heal fine
Chronic thickening
May progress to osteoarthritis
What is the treatment for traumatic synovitis?
Box rest
NSAIDs
Rehab - exercise plan
Surgery?
Hyaluronic acid and glycosaminoglycans
What animals tend to get septic arthritis?
Foals with bacteraemia
Any horse with a penetrating injury - can be tiny
What are the clinical signs of septic arthritis?
Lameness - progressive to non weight bearing
Resent palpation/flexion
Effusion
Heat
How do you diagnose septic arthritis?
Synoviocentesis
Total nucleated cell count > 10x10^9 cells/litre (most are >30 neutrophils)
Gross appearance - dark yellow/brown/red fluid
Less viscous
How can you treat septic arthritis?
Arthroscopic lavage - best
Needle flush - good for acute case
Penicillin and gentamicin
What is the gold standard septic arthritis treatment?
Systemic antimicrobials - before and after surgery penicillin and gentamycin
Arthroscopic lavage with lots of hartmanns
Synovectomy
Analgesia - NSAIDs
What is the prognosis for septic arthritis?
If surgery <24hr - 90%
Delayed surgery - bad
If left a week - 0%
65% return to athletic function
When does osteochondrosis usually present in horses?
Young horse - 2 months to 2 years
What are the clinical signs of osteochondrosis?
Lameness
Effusion
How do you investigate cases of osteochondrosis?
Lameness exam
Positive flexion
Responds to joint block?
What is the treatment for osteochondrosis dissecans?
Surgical removal of fragments - arthroscopic guidance
What is the prognosis for osteochondrosis dissecans?
Depends on extent and joint
Good for hocks
Guarded for shoulder
What does osteochondrosis dissecans predispose to?
Osteoarthritis
Quick removal of bone fragments reduces this though
Where are subchondral bone cysts most commonly seen in horses?
Medial condyle of the stifle - larger than lateral
What are the treatment options for subchondral bone cysts?
Surgical debridement
Translesional screw - crosses the cyst and stimulates more normal bone growth
Intralesional corticosteroids
What is the prognosis for subchondral bone cysts?
Very dependent on age
Better prognosis for younger horses than older horses
What is osteoarthritis classified as?
A disease process involving a disturbed balance between synthesis and degredation in joint tissues
Characterised by focal loss of cartilage, subchondral bone sclerosis and marginal osteophyte formation
What is stage 1 osteoarthritis?
Synovitis
But no morphological changes to articular cartilage
What is stage 2 osteoarthritis?
Synovitis - less acute
Mild articular cartilage damage
What is stage 3 osteoarthritis?
Chronic synovitis
Cartilage damage severe
What is stage 4 osteoarthritis?
Chronic synovitis
Full thickness loss of articular cartilage
What is a primary cause of osteoarthritis?
Chronic repetitive trauma
What are some secondary causes of osteoarthritis?
Traumatic arthritis
Articular fracture
Osteochondrosis
Septic arthritis
What are the risk factors for osteoarthritis?
Inherent - breed, age, conformation
External - use
What is the joint at the top of the hock that is high range of movement?
Tibiotarsal
What are the joints in the middle of the hock called?
Proximal and distal intertarsal
What is the joint at the bottom of the hock joint called?
Tarsometatarsal
What joints of the hock communicate in horses?
TIbiotarsal and proximal intertarsal - always
Intertarsals - sometimes communicate with each other
Tarsometatarsal and distal intertarsal - sometimes communicate
How do you investigate osteoarthritis?
Full lameness workup
What signs of osteoarthritis will you find on a lameness workup?
Reduced range of motion
Thickened joint
Crepitus
Positive flexion test and positive response to intraarticular block
What can you see on radiography of osteoarthritis in horses?
Periarticular new bone
Subchondral bone schlerosis
Narrow joint space
What are the treatment options for osteoarthritis?
Treat/limit synovitis
Cant reverse bone pathology
Arthrodesis
What is arthrodesis?
Fixing/fusing the joints so they dont hurt anymore - for low motion joints
What is the prognosis for osteoarthritis? What does it depend on?
Management rather than solution
Depends on:
Location
Severity
Treatment
Rehabilitation program
What management factors affect OA associated lameness?
Exercise routine
Box rest
Cold weather
Body weight - obesity
Farriery
What is the optimum exercise routine for horses with OA associated lameness?
Regular controlled exercise
Warm up and cool down
Water treadmills beneficial
What farriery can help horses with OA associated lameness?
Regular shoeing with optimal balance
What joint conditions is surgery beneficial for in horses? What conditions is it not beneficial for?
OCD - remove fragments
Fracture cases - stabilise, restore congruity
Not beneficial for most osteoarthritis cases - lavage better
What NSAIDs can you use to treat joint conditions in horses?
Phenylbutazone
Flunixin
Meloxicam
How do NSAIDs work?
COX inhibitors reduce prostaglandin production
When can you not use NSAIDs in horses?
Performance horses - are performance enhancing
Phenylbutazone - not for use in animals for human consumption
What are the two intraarticular corticosteroids used in horses?
Adcortyl (triamcinolone acetonide)
Depo-medrone (methyl predisolone acetate)
How do intraarticular corticosteroids work?
Phospholipase A2 inhibitors
Reduce arachidonic acid production
Reduce inflammation mediators for synovium
What is the cumulative max dose for triamcinolone acetonide?
Less than 18mg per horse
What is the cumulative max dose for Depo-medrone (methyl predisolone acetate) ?
Less than 200mg per horse
What is the safest corticosteroid to use intraarticularly? Why?
Triamcinolone - more chondroprotective so best in high motion joints
What are the complications of intraarticular corticosteroids?
Risk of joint sepsis/joint flare - sterile prep
Risk of laminitis if horse has equine metabolic disease or cushings
What is intraarticular hyaluronate?
Glycosaminoglycan
What are the functions of intraarticular hyaluronate?
Lubricant
Anti-inflammatory
Some analgesia
What is intraarticular interleukin-1 receptor antagonist protein (IRAP)?
Blocks interleukin receptors so less immune response
Taken from blood serum
What is the risks of intraarticular interleukin-1 receptor antagonist protein (IRAP)?
High risk of joint sepsis - blood serum is a good culture medium
What is pentosan also known as?
Cartrophen
What is pentosan used for?
Used prophylactically to support cartilage recovery and so improve joint function
How is pentosan administered?
4 weekly intramuscular injections
What is adequan?
Systemic polysulphated glycosaminoglycans treatment
What does adequan do to improve joint function?
Inhibits matrix metaloproteases - inhibits catabolic enzymes
Reduces inflammation
Lubricates
Repairs cartilage
How is adequan administered?
Every 4 days for 7 treatments
Given IM
What are the side effects of adequan?
Haemorrhage
What is the method of action of bisphosphonates?
Reduce osteoblast activity
What conditions are bisphosphonates used for?
Hock OA
Navicular syndrome
Diseases with excessive bone development
What are the side effects of bisphosphonates?
Binds to circulating calcium at injection so may cause GI dysfunction - colic
How are bisphosphonates administered in horses?
IV - through drip over 1 hour
With concurrent NSAIDs
How does intraarticular polyacrylamide gel (arthramid) work?
Take up into synovial lining - local effect
Non-absorbable - long duration
What improvements to synovial joints do intraarticular polyacrylamide gel have?
Shock absorption
Increases elasticity of joint capsule
Improves synovial fluid quality
What are the side effects of intraarticular polyacrylamide gel?
Minimal
Soreness
Oedema at 1-2 weeks post injection
What is intraarticular protein rich plasma?
Blood derived product containing growth factor cells and cytokines
When is protein rich plasma used in horses??
Mostly in tendon and ligament injuries
Now administered into joints
What is the situation with mesenchymal stem cells?
Still in early research/early clinical phase
But seems to be improving lameness, cartilage and synovial fluid in horses with surgically induced osteochondrosis fragments in trials
What are shock waves used on?
Most commonly used in soft tissue injuries
Can be used on joints - usually lower motion ones
What are shock waves? What is the treatment plan?
1500-2000 pulses per joint
Done once a week for 3 weeks
Why is there limited evidence for oral joint supplements?
If evidence then becomes a licensable product as so price increases reducing takeup - price themselves out of the market
How many horse owners feed joint supplements?
50%
What ingredients are in oral joint supplements?
Glucosamine
Chondroitin
Hyaluronic acid
Omega 3 fatty acids
Green lipped mussel extract
Minerals
Vitamins
