Lecture 18 & 19 - Common Surgical disorders of the forelimb and hindlimbs in the horse Flashcards
what are the most common causes of lameness?
OA and soft tissue injuries
what is another saying for navicular syndrome
palmar foot pain
what is palmar foot pain and what is its etiology
lameness originating from the podotrochlear apparatus of the forelimb (navicular bone, DDFT, navicular bursa digital cushion
abnormal, non-physiological biomechanical loading of structures (specifically long toe, under-run heels)
palmar foot pain is most common in which breeds of horses
quarter horses, thoroughbreds and warmbloods
what is the classical clinical signs of palmar foot pain?
unilateral or bilateral (bilateral is more common) forelimb lameness. it is noticed most often on hard ground or when circling on the inside limb
(going clockwise, inside foot is lame = right foot with palmar foot pain)
what is the treatment for palmar foot pain
management since its a degenerative problem
gold standard: hyaluronic acid with a low dose corticosteroid
name the 7 types of 3rd phalanx fractures:
Type 1 = abaxial/wing fracture non-articular - good px
type 2 = abaxial/wing fracture, articular - fair px, OA likely
type 3 = axial/saggital fracture, tx: screw fixation, guarded px unless young animal, OA develops
type 4 = extensor process fracture, form of OC?, tx: fragment removal, px: good
type 5 = comminuted fracture, poor px
type 6 & 7 = solar margin fracture good px (type 7 occurs in a foal)
2nd phalanx fracture - which leg is most common? what breed is most common? which tx has best px?
hindlimb > forelimb
seen most often in quarter horses
plantar/palmar eminence fractures, plating combined with PIP arthrodesis have better px
what are the two categories of first phalanx fracture?
- OCFs of the metacarapal or metatarsal joints
- common in race horses
- due to hyperextension injury
- diaphyseal fractures
- result from torsional & axial forces - aka “screwdriver” fracture
- most require internal fixation (lag screw repair)
- severe diaphyseal fracture has poor px and ends w/ euthansia
what are the two conditions we see with metacarpo/metatarso phalangeal joings (fetlock) joints?
- “POD” - palmar/plantar osteochondral disease
2. condylar fractures of MC3 / MT3
what is “POD”? what does it lead to? what does it preidspose to? which horses are most commonly affected? how is dx? how is it tx?
POD is a repetitive stress injury that results in maladaptive bone remodeling.
it leads to OA
it predisposes to MC3/MT3 condylar fractures
TB racehorses most affected
dx: bone scan, MRI and CT
tx: Rest! continued training worsens and may lead to catastrophic failure
condylar fractures of MC3/MT3: common in which horse? what do the fractures typically look like?
common in racehorses
vertrical fracture that propagates proximally and sagitally from the joint
**where do condylar fractures of MC3 / MT3 usually occur?
what types of fractures are they?
in which jiont do they occur **
lateral condyle: short and complete, more common in MC3
medial condyle: spiral, more common in MT3
what is a bucked shin? and where does it occur? what does it predispose to?
a bucked shin is a lameness from dorsal cortex maladaptive remodeling of MC3 (cannon bone)
it does not occur in MT3
it predisposes to dorsal cortical fractures
what is the most commonly incomplete “stress” fracture
dorsal cortical fracture of MC3 (aka cannon bone)
if you have a horse with an INCOMPLETE dorsal condylar fracture, what is your tx?
JUST osteostixis
what is osteostixis?
if you just have a stress fracture you take a small drill bit and make holes thru the cortex and it allows bone marrow and blood to heal the fracture
splint bone fractures - MC2&4 and MT2&4 etiology
direct trauma and exercise
they are held onto the cannon bone by the intraosseus ligament –> over exercise and stress causes a desmitis and they can pop a splint
what is the tx of splint bone 2& 4 fractures
closed fractures - rest. healing can result in a large exostosis (callus) bc these bones have a “weird” periosteum which can impinge on the suspensory ligament.
removal (partial splint ostectomy) - generally up to 2/3 of the distal aspect of either MC/MT2 or MC/MT4 without risk of destabilization of the carpus or tarsus.
osteochondral fragmentation (aka chip fractures) where are they most common and incorporating which bones?
more common on the medial side
incorporating:
- distomedial radius
- proximal/distal RCB (on exam) and ICB
- proximal 3rd CB
what is the most common site of a fracture in the carpus?
a slab fracture of the radial facet of carpal bone 3.
where are bi-articular fractures most commonly seen in the carpus?
frontal plane, rarely the sagittal plane
which joints in the tarsus communicate?
the tibiotarsal joint and proximal intertarsal joints communicate (top two)
the distal intertarsal joint and tarsometatarsal joints communicate (bottom two)
which joints communicate in the carpus?
the radiocarpal joint has no communication
the middle and carpometacarpal joints communicate
what is the most common disorder of the tarsus (aka hock)
OA
where does OA typically occur in the tarsus and what is it called?
where does the bone proliferation typically occur?
most commonly in the distal intertarsal jiont and tarsometatarsal joint - its called “bone spavin”
medial bone proliferation
what is one of the treatments for OA in the tarsus and what must you confirm before doing this tx?
chemical facilitated ankylosis: you put 70% ethyl alcohol in the tarsometatarsal joint and distal intertarsal joint. BUT you first must confirm that the distal intertarsal joint and proximal intertarsal joint do not communicate.
if you confirm that your tarsometatarsal joint and distal intertarsal joint communicate, how do you treat?
ethyl alcohol - no big deal: those joints are supposed to communicate.
when is PSD (proximal suspensory desmitis) of the forelimb worse?
lameness worse on soft ground, limb on outside of circle
what nerves do you try to localize in PSD of the forelimb?
deep br. lateral palmar n.
lateral palmar n.
med and lat. metacarpal nn.
direct infiltration
how do you treat PSD (proximal suspensory desmitis) of the forelimb?
REST AND ICE!!
sometimes surgery: fasciotomy and neurectomy
PSD of the hindlimb is common in which type of athletic horse?
english sport horses
PSD of the hindlimb is worse when _______
lameness worse on SOFT ground, limb on outside of a circle
localization of PSD in the hindlimb is more challenging in which nerves?
deep b. lateral plantar n.
med and lateral metatarsal nn.
direct infiltration
distal hock joints/low 4-point
how do you diagnose PSD of hte hindlimb?
US - challenging
radiographs
MRI - gold standard
what is the tx of PSD in the hindlimb?
- REST AND ICE!
- foot balance shoeing
- surgery
what is the surgical procedure for tx PSD of the hindlimb?
you cut the retinaculum and the nerve to release the compression around the proximal aspect of the suspensory ligament via a fasciotomy +/- neurectomy
what improves the prognosis of PSD in the hindlimb?
fasciotomy +/- neurectomy aka surgery!
what is a tx option for superifical digital flexor tendonitis? what does it increase the risk for?
superior check desmotomy
it increases the risk of suspensory ligament injury
what does superior check desmotomy predispose the horse to?
suspensory ligament desmitis
is the forelimb or hindlimb more commonly affected by lameness? and which part of this limb is most effected?
80% forelimb
95% originates distal to carpus
