Esternal Skeletal Fixator - ESF Flashcards
What are the three basic elements of ESF?
Per cutanous trans osseus pins (ESF pins or K-wires)
Connecting bars
Clamps
Advantages of external skeletal ficators?
- relative easy to apply
-faster surgical time - reduced infection rates
- faster healing times
- reduced incidence of delayed or non-union
- adjustable frame (can de-escalate)
- wounds can be managed
- implants can be easily removed
- generally the systems are economical
Disadvantages of external skeletal fixators include?
- Specliazed equipment
- less well tolerated by owners
- pins have to traverse soft tissues
- frame may fail
- soft tissue pin tract -> bacteria
- demanding aftercare
- ESF can injure patient, owner and environment
Indications for use of ESF?
1) open or infected fractures
2) comminuted fractures
3) mandibular fractures
4) fractures of the lower limb
5) correction of angular limb deformidies (hybrid, circular)
6) Immobilization of joints
7) Auxiliary fixation combined with internal repair
What are Ellis pins?
Negative threaded pins, with the junction of thread/smooth ending in the medullary canal -> less risk of pin failure
What clamps are available for ESF?
KE clamps
Maynard and JAM
IMEX SK
Securos Secur-U clamps
What are the disadvatages of the KE clamp?
Once they are assembled on the connecting bar, it is not possible to remove without entirely dissasembling the frame
It is not possible to place positive profile pins through an original KE clamp
What are the advatages of IMEX-SK and Securos Secur-U clamps?
Split clamp - allows clamps to be added and removed from ESF without disassembly
Positive profile pins can be placed
What is a Type Ia frame?
Unilateral uniplanar, halfpins
What is a Type Ib frame?
Unilateral biplanar, halfpins
What is a Type II frame?
Bilateral uniplanar, can use full or half pins
What is a Type III frame?
Biltaeral and biplanar
What kind of frame can be useful in angular limb deformities?
Circular frames - readily adjusted with hinged components and motors
Distraction at 1mm a day (0,5mm increments) untill desired length
At what rate should pins be inserted? what can minimize thermal damage?
<140 rpm power drill (if not handchuck)
Saline drip
how many pins should be placed in each fragment?
a minimum of two, three or four is ideal
Safe corridor of humerus?
Safe corridor of radius/ulna?
Safe corridor of femur?
Safe corridor of tibia?
What is wolffs law?
The internal architechture and external form of a bone is related to its function and change when that function is altered
What is the most common complication of ESF?
premature pin loosening
How to maximise rigidity with ESF?
1) 3 pins per fragment
2) largest pins possible (max 30% of bone diameter)
3) connecting bars close to patient
4) Place pins far-far near near, spacing
5) full pins for comminuted, bilateral, biplanar
6) tie-in intramedullary pin for prox limb fx
What is staged dissasembly?
conversion of a ridig initial fixation to less rigid, removing parts
What is optimal time of staged dissassembly+
6 weeks
Distance from fracture to pin?
half of bone width length away
Clamp distance from skin?
1cm
What can increase resistance to bending and axial compression in type I constructs?
Alternating the position of pins on either side of the connecting bar
Transarticular external skeletal fixators - useful for? types? consequence of prolonged fication?
Useful for periarticular injuries
may be rigid, hinged or flexible
prolonged rigid fication -> DJD
Can be used in emergency to rpevent ongoing trauma
What are key points of postoperative care of external fixators?
- careful monitoring of pin tract -> essential to minimise morbidity
- regular radiographic assessment (every 4-6w)
- dynamisation (destabilization) at 4-8w following if necessary
