Lecture 13: Fractures of the Pelvic Limb II (Exam 2) Flashcards
What can cause tibial & fibular fractures beside trauma
- Neoplasia
- Metabolic dx
When can conservative management be used
- Diaphyseal fractures
- Casts/splints can be used for closed, nondisplaced, or greenstick fractures in immature animals
Why is cast/splint fixation appropriate
- Joint above & below fractured bone (stifle & hock) can be immobilized
- Fracture should heal rapidly
- Consider if the animal will bear weight on the other 3 limbs
Are bone grafts need if dealing w/ an open reduction of a fractured tibia
AC bone graft is indicated to enhance bone healing
What fixation systems can be used for dibial diaphysis
- Casts
- IM pins w/ cerclage wire or ESF support
- Interlocking nails
- ESF
- Bone plate
What should be done pre op
- Analgesics provided
- Concurrent injuries are managed
- Prophylactic antibiotics if there is an open wound
What is the positioning of the limb w/ a closed or limited open reduction & ESF
- Prep hip to below the hock
- Donor site should be prepped
What is the positioning of the limb w/ a open reduction & plate application
Can have the leg suspended
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How do IM pins help stabilize tibial diaphyseal fractures
- Provide excellent resistance to bending
- No resistance to rotational or axial loading
- Additional implants are used to provide rotational & axial support for most fractures
When should IM pins & multi cerclage wires be used
In spiral or oblique fractures where the length of the fracture line is 2 to 3 times the diaphyseal diameter
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What is critical to avoid interfering w/ the stifle joint
Correct placement of IM pins
Why should you just say no to retrograde pinning
Risks damage to intra articular structures in dogs & patellar ligs in cats
How do you estimate appropriate pin penetration into a distal bone segment
A 2nd pin equal in length to one in the marrow cavity is used for a point of reference
When should pin size be estimated
From pre op radiograph
A (smaller/larger) pin may be needed for the curve of the tibia
Smaller
How should pins be placed starting @ the proximal tibia
Must be placed in normograde manner & manipulate the hock to ensure the pin doesn’t interfere w/ the joint
Describe how to do normograding IM pin
- Insert the pin in the medial aspect of the proximal end of the tibia
- Penetrate the bone midway btw/ the tibial tubercle & medial tibial condyle on the right medial ridge of tibial platea
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What is essential w/ tibial fractures
Contouring the plate to match norm configuration of the tibial b/c failure to reproduce can result in valgus or varus angulation of the limb
What fractures are these used to stabilize
Transverse or short oblique tibial fractures
What fractures are these used to stabilize
Long oblique or reducible comminuted tibial fractures
What fractures are these used to stabilize
Nonreducible comminuted tibial fractures
What complications can occur w/ tibial & fibular diaphyseal fractures
- Osteomyelitis
- Implant migration
- Malunion
- Delayed union
- Nonunion
What is a complication that can occur w/ ESF of the tibia
Pin loosening & pin tract drainage
What are common errors w/ tibial & fibular diaphyseal fractures
- Poor decision making w/ implant choice
- Cats treated w/ rigid ESF may be @ risk for delayed healing or nonunion
What is the prognosis of tibial & fibular diaphyseal fractures
Generally good
What are the common fractures of the proximal tibial metaphysis & epiphysis
- Usually transverse or short oblique
- May be comminuted b/c of severe trauma
What do fractures of the distal tibia in mature animals usually involve
Malleoli
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What is the prognosis of metaphyseal fractures & why
- Heal quickly
- Due to large amounts of cancellous bone around the fracture
- Trabecular bone heals w/ min formation of callus
What are physeal fractures
Through cartilaginous growth plate of proximal or distal tibia or tibial tuberosity in immature animals
Cartilaginous physis (stronger/weaker) than surround bone & ligaments
Weaker
What salter are proximal tibial physeal fractures usually
Salter I or II
What salter are distal tibial physeal fractures usually
Salter I or II
Describe radiographs
- Compare to the opp limb (particularly w/ tibial tuberosity avulsions)
- Does not provide info about crushing injuries to physis or damage to physeal blood supply
- Difficult to give an accurate prognosis for growth w/ these fractures @ time of injury
Why are pins placed @ 90 degree angles
To allow for growth
What should be used when crossing the physis in animals w/ potential growth
Smooth implants
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Describe fractures through physis of the tibial tuberosity
- Results in proximal displacement of tuberosity
- Must be reduced & stabilized to restore quadriceps
- Use 2 K wires to stabilize
- Use figure 8 ortho wire in large breed dogs
What is the prognosis of tibial & fibular physeal fractures
- Excellent
- for continued function or growth - depends on amount of damage but prognosis is good
- for trauma that crushes the physis it is poor
What is seen w/ most trauma induced physeal fractures
They sustain damage to growing cells & have guarded prognosis for growth
What is seen w/ premature closure of the proximal or distal tibial physis
- Usually results in short but straight limb
- Animal compensates by extending stifle
What can occur w/ caudal malalignment of the proximal tibial epiphysis
Increased tibial platea
What can occur w/ premature closure of tibial tuberosity physis
- Can alter conformation of the proximal tibia
- Results in impaired function & stifle DJD
