Term
| What are the types of implants used for internal skeletal fixation? |
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Definition
-intramedullary pins
-cross pins
-cerclage wires
-bone plate and screws
-interlocking nail
-tension band |
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Term
| What fracture forces are controlled by intramedullary pins? |
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Definition
-bending
-NOT rotation or axial loading |
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Term
| What is the formula for strength of intramedullary pins? |
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Definition
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Term
| Intramedullary pins must be used with an adjunct device. What are some examples? What is the exception to this rule? |
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Definition
-plate/screws, cerclage wire, external fixator
-exception: physeal fracture in young dog |
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Term
| What size must an intramedullary pins to be considered a parimary stabilizer? |
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Definition
| -60-70% of medullary canal |
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Term
| What size must an intramedullary pins to be considered an adjunct stabilizer? |
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Definition
| -30-40% of the medullary canal |
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Term
| Regarding which bones is it appropriate to consider using an intramedullary pins? |
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Definition
| -femur, tibia, ulna, and humerus |
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Term
| Which bone can we never, ever, ever use an intramedullary pin on? |
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Definition
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Term
| What are the two types of intramedullary pins? |
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Definition
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Term
| What are the two insertion methods for intramedullary pins? |
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Definition
-Retrograde insertion
-Normograde insertion |
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Term
| What is retrograde insertion of an intramedullary pin? |
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Definition
| -insert at fracture, pull through epiphysis past fracture, reduce fracture, pull backward |
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Term
| What is normograde insertion of an intramedullary pin? |
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Definition
| -insert pin at proximal end of bone, advance pin through medullary canal, cross fracture line and place |
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Term
| In which bones do we use a retrograde insertion method regarding intramedullary pins? |
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Definition
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Term
| In which bones do we use a normograde insertion method regarding intramedullary pins? |
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Definition
| -femur, humerus, tibia, metacarpals/tarsals |
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Term
| Which insertion method for intramedullary pins is preferred in the femur? Why? |
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Definition
-normograde into the trochanteric fossa
-less risk to sciatic n and physis |
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Term
| Which insertion method is used for intramedullary pins in the tibia? Why? |
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Definition
-normograde on hte medial aspect of the tibial crest
-retrograde destroys CrCL or meniscus |
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Term
| Which insertion method is used for intramedullary pins in the humerus? |
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Definition
-normograde OR retrograde
-proximolateral to distomedial direction |
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Term
| Which insertion method is used for intramedullary pins in th eulna? |
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Definition
| -retrograde insertion but cnal is very narrow distally |
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Term
| What is the indication for cross pins? Where are they used most commonly? |
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Definition
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Term
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Definition
| -stainless steel wire that completely encrompasses the bone but is used in conjection with otehr devices |
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Term
| What kind of fractures call for cerclage wire? |
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Definition
-long oblique
-lenght is 2X diameter of bone at fracture site |
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Term
| How many cerclage wires must you have? What is the only exception to this rule? |
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Definition
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Term
| Describe where exactly cerclage wire is placed in relation to the fracture. |
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Definition
-wire must be placed perpendicular to fracture with the closest wire to the fracturel ine 3-5mm
-wires are placed 1cm apart ish |
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Term
| What is hemicerclage wire? What kind of fractures call for these? |
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Definition
-wire is placed through the bone
-best for transverse fractures |
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Term
| What is the purpose of oval holes in bone plates? |
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Definition
| -oval hole allows compression of hte fracture line |
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Term
| What are the characteristics of locking plates? |
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Definition
-provide a rigid screw/plate interface
-less demand on unstable bone quality
-allows less contouring of bone plate to bone |
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Term
| What are screws used for? |
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Definition
-placement of plates
-individual use for specific fractures: lag screw |
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Term
| Describe the different types of screws available. |
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Definition
-stainless steel or titanium
-named for their outer diameter
-partially or fully threaded
-locking or non-locking
-self-tapping vs on self-tapping |
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Term
| How do standard screws stabilize implants? |
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Definition
| -they are non-locking screws that use bone/plate friction to stabilize implants |
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Term
| How do locking screws stabilize implants? |
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Definition
| -use plate/screw interface to stabilize implants with threads on screw head that lock into the plate |
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Term
| On which side of the bone do we put plates? HOw many screws do we need? |
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Definition
-plat on tension surface
-need at least 6 corticies engaged on both sides of fracture |
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Term
| For what kind of fractures do we use a compression plate? |
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Definition
| -simple transverse fractures |
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Term
| How do we add neutralization to a plate? |
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Definition
| -plate with screws with lag screws or cerclage wire added |
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Term
| What is a buttress plate? |
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Definition
| -plate carries the full load due to the fracture type |
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Term
| What is an interlocking nail? |
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Definition
-intramedullary pin with locking bolts proximal and distal
-intramedullary pin still controlls bending but locking botls control shear and rotation
0pin is larger diameter |
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Term
| On which three bones can we use interlocking nails? |
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Definition
| -femur, tibia, and humerus |
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Term
| What are the disadvantages of interlocking nails? |
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Definition
| -technically demanding and expensive |
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Term
| Why would we use a tension band? Give some examples. |
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Definition
-fracture type that has msotly distractive forces
-ex: patellar fracture, traction physeal fractures (tibial crest or olecranon) |
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Term
| What implants do we use with tension bands? |
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Definition
-kirschner wires
-rolled wire in figure eight pattern |
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