Bone Healing

Question 1

Field and Ruthenbeck, VCOT, 2018:
Pattern of optical density measures during fracture healing?
Correlation between optical density measures and the qualitative measure of bridging callus and the radiographic union score for tibial fractures (RUST)?

Answer 1

Field and Ruthenbeck, VCOT, 2018:
Optical density measures decreased through 4 weeks post-op (resorptive phase) and then gradually and consistently increased at 8-16 weeks post-op
Optical density measures showed strong correlation with measures of bridging callus and RUST

Question 2

Yeh JAVMA 2021

Time to fixator removal in cats

Factors associated with PO complications

Answer 2

Time to fixator removal in cats
-8 weeks

Factors associated with PO complications
-BW
-tibial fracture
-use of type 2 fix
-use of destabilization

Question 3

Guidelines for using locking plates

Answer 3

1. Spanning long segments of bone (3x the length of fractured segments)
2. Limiting screw-to-hole ratio to less than 0.5
3. Limiting distance between plate and bone to 2 mm
4. Leaving 2-3 screw holes empty over the fracture

Question 4

How to make a plate construct stiffer

Answer 4

1. Larger plate
2. Shortening working length (placing screws closer to fracture ends)
3. Adding implants (IM pin, second plate)

Question 5

Construct stiffness is maximized if screws are placed where?

Answer 5

At the end of the plate and near the fracture

Question 6

There is little mechanical advantage to placing more than _____ screws per fracture segment with respect to _________

Answer 6

3

Axial stiffness

Question 7

Placing a ______ screw per fragment increases ____________

Answer 7

4th

Torsional rigidity

Question 8

Screws should be omitted from holes closest to fracture gap in what size gap

Answer 8

1mm

Question 9

Star drives allows for how much greater torque than hex heads

Answer 9

65%

Question 10

Answer 10

a) SOP

b) ALPS

c) Fixin

d) PAX

Question 11

Bridging plate

Plate span ratio
-comminuted
-simple fractures

Screw density

Answer 11

Plan span ratio
-comminuted 2-3
-simple fractures 8-10

Screw density
0.5 to 0.4

Question 12

The addition of an IM pin to a bridging plate effect

Answer 12

Reduces strain = Fatigue life of plate increased

Improves overall stiffness = risk of plastic deformation decreases

Question 13

Minimal screw for plate rod

Answer 13

One bicortical
One monocortical