Pins and Nails Flashcards
What are pins otherwise known as?
K-wires
what kind of point do K wires have?
trochar
What parts of the body are commonly pinned?
small bones upper limb long bones children foot and hand patella
What is flexible wire used to achieve?
compression
What is cerclage?
encircling or crossing the fragments, pushing them together so that the cleavage lines produced by a fracture are forced together
Other than cerclage, how can wire be used?
dynamically as a tension band - utilising the power of surrounding muscles to produce compression at a fracture site - i.e. patellar fractures
What sites of the body are wires used as tension bands?
patella
olecranon
medial malleolus
In tension banding, what happens the harder the muscles work?
the firmer the fracture is compressed and the more stable it becomes
What important aspect must be considered when using cerclage or crossing bony structures?
work beneath the periosteum so that the blood supply will not be damaged
why is wire becoming less popular than it used to be?
awkwardness to use
newer techniques more elegant in execution
What is antegrade technique in IM nails?
nail is inserted into the bone from one end whilst not disturbing the fracture site at all
What piece of imaging equipment is necessary for antegrade technique?
X-ray intensifier
What is retrograde technique?
the fracture site was opened by soft tissue dissection and the fracture end delivered into the wound for reaming and insertion of the nail
What is paring off the inner surface of the bone called?
reaming
What 3 factors determine effectiveness of a nail?
material
how much of the nail is in contact with the bone
dimensions and shape of the nail and wall thickness
Why are titanium nails not used?
it is more susceptible to weakening if a hole is drilled across it or if it is abraded - known as notch sensitivity
What material are most nails made from?
stainless steel
What is the working length of a nail?
the length of a nail that transmits load from one main fragment of a fractured bone to the other
what is the relationship between working length and relive movement at the fracture site?
longer length = greater relative movement
What is the advantage of having a somewhat flexible nail?
it has a little ‘give’ on insertion so that it is easier to put in and permits the nail to deform slightly to conform to the bone shape
What is a way of reducing stiffness in a nail?
longitudinal slot - makes it much more flexile but that the expense of some bending and torsional strength
Why are nails too stiff bad?
may damage the bone if there is any discrepancy between shape of nail and bone
list some uses of IM nails
Transverse and short oblique fractures of the tibial and femoral shafts,
comminuted fractures of tibia and femur, provided cross locking capabilities are
available,
pathological shaft fractures, especially in osteoporotic bone,
delayed or non-union of the shafts of the femur or tibia,
selected open fractures, in the hands of surgeons experienced in the management of trauma.
How can the effective working length of a nail be increased?
by adding cross screws
Give an example of a plate being used together with an IM nail
fixing of a femoral neck fracture - lateral side is plated and an Im nail inserted - cross screw acts as a cantilever against the buttressed lateral femoral cortex
What are the main functions of cross screws?
maintain rotatory control
increase working length
