Long Bone Fractures: Metacarpal/tarsal Flashcards
sequelae to condylar fractures of MCIII/MTIII in equine
sclerosis of parasagittal groove
Treatment options for diaphyseal MC/MT III and IV fractures in adult bovines (2)
- double plate fixation (G.S)
- dorsal and lateral
-transfixation pin cast
signs of condylar fractures of MCIII/MTIII in equine
nondisplaced: history of lameness with acute worsening
acute displaced: acute onset of lameness following intense exercise and effusion of MCPJ/MTPJ/Fetlock + pain on palpation
condylar fractures of MCIII/MTIII in equine is repaired using 2 transcortical lag screws 20 mm apart. where does the first screw go to ensure good articular alignment?
middle of epicondylar fossa
types of transfixation pin casts
often used to treat diaphyseal MC/MT III and IV fractures in adult bovine
- pins BOTH proximal and distal
- pins ONLY proximal (requires a full limb cast)
treatment of MCIII/MTIII diaphyseal fractures in equines
double plate fixation: dorsal and lateral
dorsal is tension side
second plate can also be placed on medial side but less common
treatment of MCIII/MTIII comminuted fractures in equines
- reduce into 2 fragments by replacing butterfly fragment using lag screws
- fixate with 2 compression plates (DCP or LC-DCP): dorsal and lateral
prognosis for fractures of MC/MT III and IV in calves
good 70-80%
forelimb (85%) better than hindlimb (45%) because hindlimb is more frequently open
type I > type II
when does distal MC/MT III and IV physis close in calves
2 years old
condylar fractures of MCIII/MTIII in equine: which is more commonly injured, the MCIII or MTIII?
depends on breed!
TB MCIII > MTIII
SB MCIII = MTIII
treatment for condylar fractures of MCIII/MTIII in equine
2 transcortical lag screws placed 20 mm apart
first screw is placed in middle of epicondylar fossa
indications for using a transfixation pin cast to treat diaphyseal MC/MT III and IV fractures in adult bovine (3)
- open fractures
- severely comminuted
- if double plate fixation (which is gold standard) is too expensive
what is the max pin diameter you can use for a transfixation pin cast
-20% diameter of bone
tension side of metacarpus/metatarsus
dorsal
prognosis for racing after condylar fractures of MCIII/MTIII in equine
non displaced/incomplete: FAVORABLE (70-80%)
displaced: 50%
joint involved: risk for OA
treatment for fractures of MC/MT III and IV in calves
usually salter harris type I or II
closed reduction and external coaptation (done under heavy sedation)
cast can be full limb OR half limb ****this is the only time you don’t have to include both adjacent joints in cast
keep cast for 6 weeks (change at 3 weeks)
where do you place pins for a transfixation pin cast?
- you can place pins only proximal or both proximal and distal
- place in metaphysis (exception: in calves it’s ok to place in DISTAL diaphysis- never mid)
how much compression do you get when using compression plates?
4 mm total: 2 mm each side of fracture (since you use 2 compression screws on each side, it’s 1 mm/compression screw)
remainder of screws are placed in neutral fashion
complications common with transfixation pin cast (9)
- pin tract infection
- pin loosening
- RING SEQUESTRUM
- osteomyelitis
- pin breakage
- pin tract fracture (never place in mid diaphysis)
- osteopenia
- non-union
which has a better prognosis: fracture of MCIII/IV or MTIII/IV in calves?
forelimb (85%)
hindlimb worse (45%) because more often open
what to remember when working up a case of condylar fractures of MCIII/MTIII in equine
ALWAYS take DP AND tangential views (in order to check for bone fragments that need to be removed)
how are pins placed for a transfixation pin cast?
- place pins medial to lateral with a 30 degree divergence from frontal plane
- ideal distance between pins: 6x diameter of pin
- place in metaphysis (exception: in calves it’s ok to place in DISTAL diaphysis- never mid)
steps for placing lag screws (6)
- drill glide hole so NEAR cortex is overdrilled
- drill thread hole in FAR cortex using smaller bit
- countersink/make depression for head of screw
- measure screw length w/ depth gauge
- tap threads in FAR cortex
- insert screw with screwdriver
most common cause of condylar fractures of MCIII/MTIII in equine and most common signalment
microtrauma/overuse from highly compressive load usually in young racehorses (2-3 years old)
the only time you don’t have to include both adjacent joints in cast
treatment for fractures of MC/MT III and IV in calves: closed reduction + full limb cast OR half limb cast
which condyle is more commonly affected in condylar fractures of MCIII/MTIII in equine
lateral (85%)
medial (15%)
ideal distance between pins in a transfixation pin cast?
6x diameter of pin
fractures of MC/MT III and IV in calves are usually what type of fracture?
salter harris type I or II (both are non-articular)
rules to remember when placing a transfixation pin cast to treat diaphyseal MC/MT III and IV fractures in adult bovine
- max pin diameter: 20% diameter of bone
- place pins medial to lateral with a 30 degree divergence from frontal plane
- ideal distance between pins: 6x diameter of one pin
- ideal location for pins: metaphysis (exception: in calves ok to place in distal diaphysis but NEVER in mid diaphysis- can lead to fracture)
- make cast span as proximal as possible
