Test 1: bone plates Flashcards
bone plates counteract what forces
bending, rotation, tension, compression and shear
advantages of bone plate
allows early return to function
less rechecks than other methods
avoids bandage morbidity
what kind of fractures can not be healed with bone plating
physeal
high grade open fracture
disadvantages of bone plating
Open reduction and stabilization
* Disrupts soft tissues and blood supply
Expense of equipment and supplies
Training and experience necessary
what are bone plates made of
316L stainless steel
titanium alloy
1.1-4.5 mm
anatomic vs biological fixation
anatomic- put all the pieces back together, rigid stabilization, direct bone healing, used for simple and articular fractures
biological- allow bone to heal by indirect bone healing, just line up the joints and leave middle alone
what is load sharing for anatomic reconstruction
bone is reconstructed in a way that weight of animal is distributed between bone and the implant- can use weaker implant
have rigid stabilization- direct bone healing
when to use anatomic reconstruction
simple fracture (only 2 pieces)
articular or per-articular fracture (joint surface)
army navy retractor
goal of biological fixation
restore joint alignment and limb length
do not put all the pieces back together, work by indirect bone healing
less invasive then anatomic reconstruction
name 3 bridging implants used for biological fixation
plate-rod
locking plate
double plate
plate screws
hold the plate to the bone
may serve as lag or position screws depending on how they were placed
— screw hold fragments in place
position screw
no compression
thread hole drilled in each fragment
how does lag screw work
drill hole as big as thread= glide hole
second piece has thread hole which is slightly smaller then screw shaft
second piece is then pulled toward the first
used for fragment reduction= applies compression across fracture line
— screws are used for fragment reduction. Applies — to fracture line
lag
compression (pulls pieces together)
lag screws are placed — to the fracture line
perpendicular
how does non-locking plate work
Plate must be in contact with the bone
Screws must be tight
Friction between plate and bone= stability
2-4 screws per fragment
plate same length as bone
compression plating
non-locking plate
as you advance screw it shifts to the side= compression
compression plate should be positioned on which side of the bone
tension surface
neutralization plating
used for oblique fractures
fix fracture with cerclage wire or lag screw, then plate added to share the load
used for anatomic reconstruction
bridging plating
bone does not share the load
try to fix bone alignment and length, allow for secondary/indirect healing
when to use bridging plating
comminuted diaphyseal fracture (mid shaft many pieces)
mal-union/angular limb deformity- opening wedge osteotomy
locking plate vs non-locking plate
locking plate= screw locks into plate, plate does not touch bone
non-locking= plate and bone need to touch
what type of plate can use monocortical screws
locking plate
better to use bicortical screw, because stronger but not needed
plate should be same length as bone and as close to bone as possible, but does not have to touch to work
