Long Bone Fractures: Metacarpal/tarsal

Question 1

sequelae to condylar fractures of MCIII/MTIII in equine

Answer 1

sclerosis of parasagittal groove

Question 2

Treatment options for diaphyseal MC/MT III and IV fractures in adult bovines (2)

Answer 2

• double plate fixation (G.S)
  
  • dorsal and lateral

-transfixation pin cast

Question 3

signs of condylar fractures of MCIII/MTIII in equine

Answer 3

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

Question 4

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?

Answer 4

middle of epicondylar fossa

Question 5

types of transfixation pin casts

Answer 5

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)

Question 6

treatment of MCIII/MTIII diaphyseal fractures in equines

Answer 6

double plate fixation: dorsal and lateral

dorsal is tension side

second plate can also be placed on medial side but less common

Question 7

treatment of MCIII/MTIII comminuted fractures in equines

Answer 7

1. reduce into 2 fragments by replacing butterfly fragment using lag screws
2. fixate with 2 compression plates (DCP or LC-DCP): dorsal and lateral

Question 8

prognosis for fractures of MC/MT III and IV in calves

Answer 8

good 70-80%

forelimb (85%) better than hindlimb (45%) because hindlimb is more frequently open

type I > type II

Question 9

when does distal MC/MT III and IV physis close in calves

Answer 9

2 years old

Question 10

condylar fractures of MCIII/MTIII in equine: which is more commonly injured, the MCIII or MTIII?

Answer 10

depends on breed!

TB MCIII > MTIII

SB MCIII = MTIII

Question 11

treatment for condylar fractures of MCIII/MTIII in equine

Answer 11

2 transcortical lag screws placed 20 mm apart

first screw is placed in middle of epicondylar fossa

Question 12

indications for using a transfixation pin cast to treat diaphyseal MC/MT III and IV fractures in adult bovine (3)

Answer 12

• open fractures
• severely comminuted
• if double plate fixation (which is gold standard) is too expensive

Question 13

what is the max pin diameter you can use for a transfixation pin cast

Answer 13

-20% diameter of bone

Question 14

tension side of metacarpus/metatarsus

Answer 14

dorsal

Question 15

prognosis for racing after condylar fractures of MCIII/MTIII in equine

Answer 15

non displaced/incomplete: FAVORABLE (70-80%)

displaced: 50%

joint involved: risk for OA

Question 16

treatment for fractures of MC/MT III and IV in calves

Answer 16

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)

Question 17

where do you place pins for a transfixation pin cast?

Answer 17

• 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)

Question 18

how much compression do you get when using compression plates?

Answer 18

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

Question 19

complications common with transfixation pin cast (9)

Answer 19

• pin tract infection
• pin loosening
• RING SEQUESTRUM
• osteomyelitis
• pin breakage
• pin tract fracture (never place in mid diaphysis)
• osteopenia
• non-union

Question 20

which has a better prognosis: fracture of MCIII/IV or MTIII/IV in calves?

Answer 20

forelimb (85%)

hindlimb worse (45%) because more often open

Question 21

what to remember when working up a case of condylar fractures of MCIII/MTIII in equine

Answer 21

ALWAYS take DP AND tangential views (in order to check for bone fragments that need to be removed)

Question 22

how are pins placed for a transfixation pin cast?

Answer 22

• 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)

Question 23

steps for placing lag screws (6)

Answer 23

1. drill glide hole so NEAR cortex is overdrilled
2. drill thread hole in FAR cortex using smaller bit
3. countersink/make depression for head of screw
4. measure screw length w/ depth gauge
5. tap threads in FAR cortex
6. insert screw with screwdriver

Question 24

most common cause of condylar fractures of MCIII/MTIII in equine and most common signalment

Answer 24

microtrauma/overuse from highly compressive load usually in young racehorses (2-3 years old)

Question 25

the only time you don’t have to include both adjacent joints in cast

Answer 25

treatment for fractures of MC/MT III and IV in calves: closed reduction + full limb cast OR half limb cast

Question 26

which condyle is more commonly affected in condylar fractures of MCIII/MTIII in equine

Answer 26

lateral (85%)

medial (15%)

Question 27

ideal distance between pins in a transfixation pin cast?

Answer 27

6x diameter of pin

Question 28

fractures of MC/MT III and IV in calves are usually what type of fracture?

Answer 28

salter harris type I or II (both are non-articular)

Question 29

rules to remember when placing a transfixation pin cast to treat diaphyseal MC/MT III and IV fractures in adult bovine

Answer 29

• 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