Coffin OA Flashcards
What is OA
degenerative joint disease
what aged horses do we typically see OA in
middle aged –> older horse
T/F we won’t see OA in a young horse
False
Describe the typical signalment for coffin OA
common
all types of horses
front feet more than hind
Describe the typical signalment for pastern joint OA
Uncommon
Heavier breeds – cobs & hunters
Hind feet more commonly affect than front
List 7 predisposing factors for OA
genetic predisposition
work load (repetitive impacts)
work type (faster gait, landing after jumps)
work surface
hoof imbalance/conformation
nutrition In early life
previous injury
in terms of predisposing factors what does:
- workload (repetitive impacts), work type (faster gait, landing after jumps) and work surface (hard vs cushioned) come under
concussion
why does hoof imbalance/conformation lead to OA?
abnormal forces in joint area
what typical hoof conformation/imbalance results in OA?
Long Toe Low Heel conformation (broken back)
Describe a typical history for OA
low grade lameness
often bilateral FL lameness
often insidious onset, can be sudden
reduced performance w/o obvious lameness
Describe what is typically seen on clinical exam with coffin OA
effusion in coffin joint (palpate just proximal to coronary band -> squishy)
broken back hoof pastern axis (w/ long toe low heel conformation)
Describe what is typically seen on dynamic exam with coffin joint OA
sound at walk
mild lameness at trot (may be bilateral)
more obvious when lunged with lame limb to inside
worse on hard ground
moderate response to distal limb flexion
why would horses with OA be more lame on hard ground than soft?
more concussive forces
if we suspect coffin OA, how would we isolate the source of the lameness?
Palmar digital nerve block
distal interphalangeal (coffin) joint block
after doing the PDNB (palmar digital nerve block) - how long should we wait before looking at the horse again?
10-15 mins
after doing the coffin joint block, how long would we wait before looking at the horse again?
5 mins
if we suspect OA, once we have localised our lameness to the foot area what would we do next?
Radiography - LM view
List 4 possible findings we may see on rads with OA of coffin joint
- osteophytes @ extensor process (spiky bone) and palmar aspect (near to lateral condyle)
- new bone growth where joint capsule attaches to P2
- loss of roundness of joint surfaces
- mineralised opacity in joint space
T/F MRI or CTs are needed for diagnosis of coffin OA
False
When would MRI be useful for in diagnosisng coffin OA
allows diagnosis of additional pathology e.g. oedema in P3
What are the 2 main treatment options for coffin OA
NSAIDs
Intra-articular corticosteroids
which NSAIDs could we give for OA
Phenylbutazone or Suxibuzone
when would NSAIDs be given for OA
each day ‘or
can be used as required
List 2 advantages of using NSAIDs for treating OA
cheap and easy to give (in food)
-treats entire horse (good if multiple joints affected)
List 3 disadvantages of using NSAIDs to treat OA
systemic side effects:
gastric ulceration
RDC- right dorsal colitis
liver and kidney inflammation
Name 2 intra-articular corticosteroids that can be used to treat OA
Triamcinalone or Methylprednisolone
List 3 advantages of intra-articular corticosteroids to treat OA
Very potent
focuses on the joint
lasts for approax 6 months (can be repeated)
List 3 disadvantages of using intra-articular corticosteroids to treat OA
requires skill to administer
will only treat one joint
rare side effects: laminiatis + joint sepsis
aside from corticosteroids, List 6 other intra-articular medications can we give for OA?
Hyaluronic acid
Polyacrylamide gel (Arthromid)
Chondrogenically primed stem cell allograft (Articell)
Platelet Rich Plasma (PRP)
Interleukin 1 receptor antagonist protein (IRAP)
Bone Marrow Aspirate Concentrate (BMAC)
Describe how does hyaluronic acid joint injections work for OA?
lubricates the joint, reduced friction
(tend to give alongside steroids in high motion joints)
Describe how does polyacrylamide gel joint injections work for OA?
hydrogel filler to lubcricte the joint + give cushioning effect
Describe how do chondrogenically primed stem cell allograft joint injections work?
stem cells from another horse - stimulates chondrocyte repair
Describe how do platelet rich plasma joint injections work?
horses own plasma- releases nutrients and growth factors
Describe how does interleukin 1 receptor antagonist protein joint injections work?
anti-inflammatory protein - normally present in joint from blood autograft
Describe how do bone marrow aspirate concentrate joint injections work?
taken from sternum or tuber coxae and injected into joint
in addition to joint injections and NSAIDs, what further medication types do we have for OA?
slow acting disease modifying OA agents (SADMOD) - many exist but lack evidence
- oral joint supplements (glucosamine, chondroitin, hyaluronic acid) - doesn’t do any harm to give
- pentosan polysulphate
why might it be a good idea to use SAMODs even though there is not a lot of evidence for their efficacy?
doesn’t do any harm
Describe how does pentosan polysuphate (cartorophen) work?
accelerates chondrocyte and synoviocyte metabolism
reduces MMP production -> anti-inflammatory and cartilage repair effects
Aside from medications, what other form of tx is needed for coffin OA?
corrective farriery
List 3 farriery considerations would we typically use for OA
shorten toe
support heels (bar shoes)
add cushioning ( rubber pad or sole packing under shoe)
what other option is there for managing OA aside from medications + farriery
surgery
Name 2 possible surgies could we perform to manage OA
arthroscopy
palmar digital neurectomy
List 2 situations can we use arthroscopy to treat OA
If osteochondral fragment present
To debride necrotic cartilage
Describe palmar digital neurectomy
Section of nerves removed
Long term desensitisation of the foot
Only if other therapies are unsuccessful
What is a possible problem with performing a palmar digital neuroectomy
if something else occurs like an abscess then you won’t know until it has progressed
T/F it isn’t possible to get ris of OA
true
Describe possible future managements of OA
manage workload
careful what surfaces you work them on
ongoing vet treatment and farriery- repeat injections every few years
