Final: Fracture fixation- pins, ESF, screws, plates, interlocking nails Flashcards
Which of the following is not a commonly used descriptor for fractures?
Displacement
Reparability
Communication with external environment
Reparability
What are the indications for external coaptation (closed reduction) of a fracture?
Below elbow or stifle
Bone will be stable after reduction
Fracture expected to heal quickly and without disease (i.e. young patient)
Small dogs or cats
E.g. Greenstick, Intact periosteal sleeve, Impaction fractures
What type of ESF is unilateral and uniplanar? What aspect of the tibia is this placed? Femur? Humerus? Radius?
Type 1A
Tibia= Medial
Femur, Humerus= Lateral (usually w/IM pin)
Radius= Cranial and medial
How long does an oblique fracture have to be for it to be considered ‘long’?
>2 x diameter of bone
Under which forces is an oblique fracture stable and unstable?
Unstable in compression
Less unstable than transverse in bending, rotation
Stable in torsion
What classification of open fracture involves a lot fo soft tissue trauma but with enough tissue for closure?
Type 3A
Classify this fracture
Simple mid-diaphyseal transverse fracture of the femur
What are postitive profile threaded pins?
The threads of the pins stick out beyond the core/base of the pin
What are the indications for full cerclage wire? When is the use counterindicated?
Long oblique or spiral fractures (fx line at least 2x bone diameter)
C/O’d: Short oblique fractres, fractures with more than 3 segments, unreducible fractures
What functions do these plates serve?
A= Compression
B= Neutralization
C= Holding collpased epithysis in position
What are advantages and disadvantages of closed reduction?
(+): Preserves soft tissue and blood supply, less risk of infection, decreased operating time
(-): Difficult to obtain accurate reduction
What types of fractures can be compressed by a plate?
Transverse
Nearly transverse
Any other type will shear
In what fashion must interlocking pins be placed? What type of fracture can they be used for? What forces do they resist?
Normograde
Mid-diaphyseal fractures of humerus, femur and tibia
Resist bending, shearing and rotation
3 or more pieces upgrades a simple fracture to a _____ fracture.
Comminuted
What is the most common cause of fractures in small animals?
HBC
T/F: The Salter Harris fracture classification system can only be used in the bones of young patients.
True
What type of plate is used here?
Bridging (Buttress)
What are the 3 methods to obtain fragment apposition and potentially compression of a short oblique fracture?
Lag screws
Skewer pin
Hemicerclage wire
In addition to something else, not alone!
What complication fo you risk if you were to place an ESF into the humeral diaphysis blindly?
Nerve or vessel damage (Specifically the radial nerve)
Which is why you don’t do that
T/F: ESF can only be used for open fractures.
False
What type of fixation is ideal for this situation?
Interlocking pins
What type of plate is this?
LC-DCP
Which type of plate as a neutralizing or bridging application but does nnot compress a fracture? What is it often combined with?
String of Pearls
Rods/IM pin
What type of pin is a Steinmann pin?
Intramedullary
What classification of open fracture involves exposed bone and stripped periosteum but no damage to arterial blood supply?
Type 3B
What type of plate can you place on an oblique or comminuted fracture?
Neutralizing plate
All screws neutrally positioned and same diameter
Does compressing a fracture using a bone plate stimulate bone healing and provide osteoinduction?
No
It provides a stable mechanical environment
_______ fractures go in the same direction as the long axis of the bone.
Fissure
What type(s) of plate(s) can be used as an alterative to cross pinning in some fractures?
L or T plates
What are advantages to open fracture reduction? Disadvantages?
Direct visualization of the fracture to facilitate reconstruction
Allows placement of implant
Allows load sharing
Bone grafts
(-): Increased surgical time, increased soft tissue trauma and compromised blood supply, increased risk of infection
What type of fracture is this? Does it require surgical repair? If so what kind?
Greenstick or Incomplete
No, inherrently stable
What screws are meant to lock into a LCP?
Locking head screw
LCP= locking compression plate
On which bones can a tyoe 2 ESF be placed? On which bones is it counterindicated?
Radius and tibia (medial to lateral)
Cannot use on femur or humerus (no room to go through whole bone due to axilla or groin)
Which type of Salter Harris fracture can cause angular deformities because it can result in the eventual cessation of physeal function (which may not be radiographically evident immediatly)?
Type V (5)
Which of the most commonly used bone screws has a larger pitch and deeper thread? What type of bone are these for?
Cancellous
Metaphyseal or epiphyseal bone (softer bone)
What classification of open fracture involves an external object having penetrates soft tissue with mild soft tissue trauma?
Type 2
What is stack pinning? Does it imporve the resistance to bending forces?
2 or more IM pins used to fill medullary cavity
No advantage found
If a fracture runs through the physis and a portion of the metaphysis what Salter Harris classificaiton is it?
Type II (2)
What type of force do Steinmann pins resist?
Bending (only)
What type of fracture is caused by torsion forces?
Spiral
What type of screw is fully threaded and used in diaphyseal bone?
Cortical screw
Also smaller pitch and shallow dense threads
Which cortex is engaged when placing a lag screw?
The far cortex
What plates are commonly used in areas where there is very little soft tissue coverage?
Tubular plates
A Salter Harris Type 1 fracture is a slip fracture of which zone?
Hypertrophy
What is the post-op care protocol after the placement of an ESF?
Rads immediately post-op and then after 4 weeks and after 8 weeks
Leash walks
Clean pin ports and change bandage daily
Fractures cna be classfied by the direction of the fracture lines. The directional term is relative what?
The long axis of the long bone
What is the spherical gliding principle and to what does it apply?
Compression obtained by tightening screws down a ramped hole
Applies to compression plate placement- pushes the fracture together from either side
What type of ESF is this?
Type 3 (Bilateral-Biplanar)
Rarely used
What are the smallest Steinmann pins called?
Kirschner Wires
What is the lowest Salter Harris classification that can be called “articular”?
Type III (3)
What type of plate can sometimes be used as an alternative to tension banding?
Double hook plates
Classify this fracture
Simple mid-diaphyseal spiral fracture of the femur
The use of what instrument is indicated for the open reduction of an oblique fracture?
Self-retaining pointed reduction bone forceps
What type of screw has a central hollow core? What is it used for?
Cannulated screw
Fractures that are diffucult to stabilize (e.g. sacroiliac luxation)
Bone plates must be placed on the tension side of the bone. What are the tension sides of the femur, tibia, humerus, and radius?
Femur: Lateral
Tibia: Medial
Humerus: Depends on fracture, any side
Radius: Cranial
What type of fixation is indcated for avulsion fractures of tension physes and for the closure of an ostectomy?
Tension Band wire
What method of stabilization are used ofr Salter Harris type I fractures of the proximal humerus or femur? How many k-wires are placed?
Diverging pins
3 (in triangular fashion)
T/F: A spiral fracture is a simple fracture.
True
What type of cortical screw is partially threaded and what are they used for?
Shaft screw
For lag application in diaphyseal bone (avoids threads engaging cis cortex)
What pin angle do you need when using smooth pins? Treaded pins?
Smooth= 60-65deg
Threaded (positive profile)= 90deg
T/F: Circle/ring fixators can be placed open or closed if the fracture is adequately reduced.
True
Closed is desirable
On what bones and which aspects of those bones do you place a Type 1B ESF?
Radius- Craniomedial or Craniolateral
Tibia - Craniomedial
Provides more fixation than type 1A; Unilateral Biplanar
What is the problem with the placement of this IM pin?
It has been placed retrograde in the tibia and is thus piercing the articular surface
What is the advantage of using a LCP over a DCP?
Combi holes allow you to plate either conventional or locking head screws, eliminating the need for perfect countouring
Can be placed using MIPO (minimally invasive plate osteosynthesis) which does not require plate to bone friction (see pic)
How much of the meduallary cavity must a pin take up if you are using only a pin? What if you are using a pin and an ESF? Pin and bone plate?
70%
60%
50%
A fracture of the metacarpal area warrents external coaptation to the level of the _____.
Elbow joint
If you notice a wound above a fracture, what must you assume about this fracture?
That it was once open
T/F: Salter Harris type VI (6) is more common than Type V (5) and involes partial physeal closures resulting from damage to a portion of the physis and causing asymmetric physeal closure,
True
What classification of open fracture requires arterial repair for limb salvage?
Type 3C
In lag screw application a ______ hole is drilled in the far cortex corresponding to the __________ of the screw, while a _____ hole is drilled in the near cortex corresponding to the __________ of the screw threads.
In lag screw application a SMALLER hole is drilled in the far cortex corresponding to the CORE DIAMETER of the screw, while a LARGER** hole is drilled in the near cortex corresponding to the **OUTER DIAMETER of the screw threads.
When placing a bone plate, you should span the entire ______ of the bone (if possible), at least ___ screws should be placed which should engage at least ____ cortices on each side of the fracture line.
When placing a bone plate, you should span the entire DIAPHYSIS/LENGTH of the bone (if possible), at least THREE (3) screws should be placed which should engage at least SIX (6) cortices, on each side of the fracture line.
What type of Salter Harris fracture runs through the epiphysis, across the physis and through the metaphysis?
Type IV (4)
What method of fixation involves pins that have a slight bend? How many points of contact does each pin have? What fractures is it indicated for?
Rush pinning
3
Very distal or very proximal longbone fractures (same indication as fro cross pins, but more technically difficult)
Classify this fracture.
Comminuted reducible mid-diaphyseal fracture of the femur with a butterfly segment
What wire technique is used for short oblique fractures?
Hemicerclage wire
(wire passed through pre-drilled holes and around IM pin)
A bone plate with oblong holes is referred to as a _______ because compression can be applied to the bone through the action of the screw being tightened.
Dynamic compression plate (DCP)
In a fracture that is on the distal end of a femur, cross pins should cross ____ to the distal segment of the fracture.
Proximal
In which of these bones can IM pins NOT be used?
Tibia
Ulna
Radius
Metacarpal
Metatarsal
Humerus
Femur
RADIUS
(because it is slighly bowed and location of articular surfaces)
Which forces to bone plates resist?
All of them!
How many pins are indicated per segment when placing an ESF? How far from the fracture must you place them?
At least 2
>/= 2 pin diameters from the fx
What is the goal of fracture repair in our small animal patients?
Early return of full function of the limb
Ambulation aids in bone healing and remodeling
What plate is used in areas that require complex plate contouring, like on the mandible? What is a disadvanage of using this plate rather than a DCP?
Reconstruction plate
Not as strong as DCP
In which bone can an IM pin only be placed in normograde fashion?
Tibia
Which direction in pin placement causes less damage to the blood supply at the level of the fracture site?
Normograde
Full cerclage wire must be placed at least ___cm from the fracture ends and ___cm apart.
0.5
1
When is a position screw used?
When placement of a lag screw will cause the bone fragment to collapse, to maintain the position of a fragment
Note- Same size hole drilled in both cortices, unlike lag technique
In addition to use with IM pins, ESF, and plates, what can orthopedic wire be used for?
Suturing flat bones together
____________ are manufactured so that there is limited contact between the plate and bone to minimize interruption of blood flow. This is accomplished by undercutting the bottom surface of the plate between the screw holes. Undercutting the screw holes also evenly distributes the stress on the plate, eliminating the effect of the plate hole as a stress concentrator.
LC-DCP
What classification of open fracture is associated with a small lacteration (<1cm) with bone penetrating through skin?
Type 1
What type of fracture is caused by bendig forces? What about bending and axial compression? What about axail compression alone?
Bending= Transverse + small butterfly segment
Bend+Compress= Comminuted + butterfly segment
Compress= Oblique (long, short)
A fracture of the tarsus warrants external coaptation that goes _________.
Beyond the stifle half way up the femur
Classify this fracture.
Simple mid-diaphyseal long oblique fracture of the femur
Under which forces is a transverse fracture stable and unstable?
Stable in compression
Unstable in bending and rotation
Ideal for load sharing
What type of ESF is indicated for complex fractures and angular deformities as well as for limb shortening or lengthening procedures (bone grafts, ?
Circular/ring Fixator
What is tapping?
Creating threads in the bone for a screw to engage into
Pic is of self-tapping screw
