Bone Spavin-P1 fractures Flashcards
What is one of the most common causes of hindlimb lameness in the horse?
Bone Spavin
What is Bone Spavin?
DJD of the distal tarsal joints specifically:
- Distal intertarsal (DIT)
- Tarsometarsal (TMT)
- if severe enough it will be visible on the medial aspect of the joint
- May see significant osteophyte formation
How do you Diagnose Bone Spavin?
- history
- PE
- Lameness evaluation
- Blocks
- radiographs
- nuclear scintigraphy
- MRI
How many joints are there in the HOCK?
the hock is not a joint!!! it is comprised of 5 joints:
1) tibiotarsal joint
2) Proximal intertarsal joint
3) Distal intertarsal joint
4) tarsometatarsal ojint
5) talocalcaneal joint
What does poor conformation predispose to ?
OSTEOARTHRITIS
Where would Bone spavin be visible on a horse if it was severe enough?
on the medial aspect of the hock
What type of conformation is typically associated with Bone spavin?
Sickle hocked
When evaluating a horse for conformation what should you make sure to check/ do so that you do not get an artifact conformation?
- horse should be standing on even ground
- horse should be standing square
What is a Cow hocked horse?
KNOCKING
-hocks are more axially placed under the limb
What breed of horse tend to have abnormal conformations?
Western performance horses used for:
- cutting
- reining
- roping
- barrel racing
*bone spavin is commonly seen in these horses
GO through YOUR radiographic views
cant put pics :(
DLPMO = macdonalds sign or old man on a ledge
DMPLO =
Lateral = no separation of trochelar ridges, talocalcaneal joint visible
When evaluating bone spavin in a horse how many grades are there?
4 grades
What are the causes of Bone Spavin?
1) poor conformation
2) chronic repetitive
- compression
- torsion
- shear strains
What are the qualities of Nuclear scintigraphy that make it useful in diagnosing Bone Spavin?
1) sensitive
2) non specific
3) details cortical bone disease and stress fracture
What are the qualities of MRI that make it useful in diagnosing Bone spavin
Sensitive and Specific for examination of soft and hard tissue in joints!!!!!
*can be as good as arthroscopy for detecting subchondral lesions
What is the most common form of treatment conservative or surgical ?
Conservative- medial management
What surgical treatment can be done for Bone Spavin?
- Ankylosis of the TMT and DIT joints
- Cunean tenectomy (good outcome (83%)
What does medical management as a treatment for Bone spavin involve?
1) IA injections
- corticosteroids
- chondroproteectants
- autologous anti-inflammatories
2) Phenylbutasone (systemic)
3) exercise adaptation
4) corrective shoeing
*Olden days: Bute em and Ride em !
What is a Cunean tenectomy used to treat?
How does it work?
What is the prognosis?
- Bone Spavin
- decreases rotational and shearing on the distal tarsal joints, providing comfort for the patient.
- REALLY GOOD (83% in a large study)
What are the two methods of Ankylosis for Bone Spavin?
Ankylosis of the TMT and DIT joints
1) Mechanical
- drill out joints using drill bit
- Nd: YAG or Diode laser
2) Chemical
- 70% ethanol
- MIA (monoiodoacetate) NO LONGER DONE…. DONT do it…its causes severe pain
Why can you not use chemical ankylosis in the pastern joint?
there is too much movement!!!!
Which joint can you use Chemical ankylosis in and why?
TMT and DIT joints!!!!!
- this is because their primary job is absorption of compressive forces so there is not alot of movement in the joint
- they respond really well to Ethanol (70%) injections
unlike the PASTERN!!!!
MIA (monoiodoacetate) can be used to chemically ankylose a joint?
it can but it should NOT
When mechanically ankylosising a joint what function drilling have?
- a method for getting rid of cartilage
Describe Transarticular drilling
-Medial approach, distal to cunean tendon
-3.2mm, then 4.5mm drill bit
-create 3 drill tracts at 30 degree diverging angles
(one entry site, 3 different directions)
spot welding, to stabilise site
What diagnositc tools can and should be used during Transarticular drilling?
-Fluroscopy or Radiographs
What post-operative care should be taken when drilling?
1) phenylbutazone
2) bandaging x2 weeks
3) hand walking 2 weeks post op
4) light riding 3-4 weeks post op
5) most improved 4-5 months post op (back to work)
What is the return to soundness after surgical ankylosis? (DRILLING)
59-85%
ave 7.5 months
How does laser facillitated ankylosis work?
What benefit does it have compared to drilling
destroys cartilage by superheating and vaporizing synovial fluid
- less pain/ discomfort post op
- promotes partial ankylosis
But significantly less fusion of the distal tarsal joints compared with other techniques!!!
What is the prognosis after treatment with Ethyl alcohol?
- lameness resolved in 86% of horses with Bone spavin within 3 months
- lameness improved in 52% of horses evaluated after TMT injection of ethanol
How much ethyl alcohol can be injected for chemical ankylosis?
- 3ml 70% ethyl alcohol
- lameness eliminated within 3days to 3months
What joint always communicates with the Tibiotarsal joint?
Proximal intertarsal
Why dont we want to chemically ankylose the PIT or TT joint?
- Tibiotarsal has the most movement
- PIT joint communicates with the TT joint
Fractures of the first phalanx are common in which breed of horse? WHY
Race horses: 3 yr TB, acutely lame (grade 5/5)
-Torsion with axial weightbearing!!!!
Why should you not block a horse with P1 fracture?
- horse usually presents acutely lame (grade 5/5)
- Painful
- Likely to make it worse!!!!
How Do you Diagnose a P1 fracture?
Radiographs!!!
- complete/incomplete
- closed / open (would see gass opacity)
- sagital etc…
How do you treat a P1 Fracture?
Internal fixation with screws and cast
- first screw proximally in order to align the articular surface!!!!!!! (within 5mm of sagittal groove)
- rest of the screws should be 2 cm apart
- LAG screw placement
How long should a distal limb cast for a P1 fracture stay on?
What is the prognosis?
2-6 weeks
prognosis dependent upon resultant fetlock and pastern DJD
Why is the prognosis for P1 dependent on DJD?
How well did you realign the articular surface, because there is a lot of movement here
ITS an articular surface!!!!!!
What would conservative treatment of a P1 fracture include?
STRICT stall rest
-short incomplete sagittal fractures
but if they dont do well need to go back and put lag screws and cast
What is the return to function for Comminuted P1 fractures in a horse?
Why?
POOR
- significant articular damage
- worry about contralateral limb laminitis
- OA
When would you do Fetlock Arthrodesis?
Why?
SALVAGE procedure
- complete rupture of SDF, DDF and SL
- septic arthritis
- Fractures: medial and lateral sesamoid, cannon bone and P1
To keep a breeding (valuble) horse, to maintain genetics!
Why is the prognosis for fetlock arthrodesis and pastern joint arthrodesis different?
fetlock = POOR Pastern = GOOD
due to motion in the fetlock, its an articular surface
-huge range of flexion and extension
What are the indications for Fetlock Arthrodesis?
1) complete rupture of SDF, DDF, SL
2) septic arthritis
3) fractures: medial and lateral sesamoid, cannon bone and P1
