SA Othro- Internal Fracture Repair

Question 1

Factors for fracture decision making

Answer 1

Info abt the patient
Info abt the fracture
Knowledge of fracture biomechanics and healing
Knowledge of fixation devices

Question 2

Movement for fracture decision making

Answer 2

Bending
Torsional, rotational
Compressional (axial load)
Distraction

Question 3

How to make fixation surgery easier

Answer 3

Pre op planning
Measuring, placement, pre and post op X-ray
Use contra lateral limb as a reference map

Question 4

General rules for fixations

Answer 4

Vascularity !!! Makes bone more viable
Avoid stripping periosteum - they will increase blood supply
Your tools should be delicate to protect bone fragment/periosteum
Reconstruction should be not 110%, only fix what is mechanically necessary

Question 5

Stages for bone healing

Answer 5

Osteogenesis - Cells surviving in the transplant
Osteoinduction - induces bone formation
Osteoconduction - scaffolding
Osetopromotion - enhance cells, platelet-rich-plasma

Question 6

Places to collect for bone graft

Answer 6

Proximal humerus (want cancellous bone)
Wing on ilium
Distal femur
Proximal

Question 7

Chemicals from bone grafts to stimulate bone formation

Answer 7

BMP 2, 4, 7
TGF - B

Question 8

What splint could you consider as management of a GSW fracture until surgery?

Answer 8

Spica splint - could increase pain and swelling
Cage rest is ideal

Question 9

Causes of fixation failure

Answer 9

Stress= force/unit area
Strain = change in length / original length

Question 10

Plate rod fixation

Answer 10

Plate + rod reduces sliding/instability (rotation/compressive forces)

Question 11

Bending moment

Answer 11

Force x distance (from force to implant)
Bending moment for plate greater due to force being applied over larger distance

Question 12

Best feature of external fixators

Answer 12

Preserves extra osseous blood supply
Versatile, adjustable, open or closed applications

Question 13

Types of external skeletal fixators

Answer 13

Type I - uniplanar
Type II - biplanar
Type III - uniplanar + biplanar
Hybrid

Question 14

Type Ia of fixations

Answer 14

One sided, single construct on side, w pins

Question 15

Type Ib

Answer 15

Two fixators typically 90* from each other, screws coming into bone at both sides

Question 16

Maximal type II

Answer 16

180* apart rods (2)
Screw and pins go all the way across instead of ending in the bone

Question 17

Minimal type II

Answer 17

Two rods with two fixators going all the way through and middle screws end in bone

Question 18

Tie - in fixator

Answer 18

Rod enters bone with external fixators and screws enter one side

Question 19

Type III

Answer 19

Type I and II together, rod create a triangle around the bone w screws entering in 3 different places

Question 20

Hybrid ESF

Answer 20

Ring (partial or complete) surrounds bone, wire or pins fixation secure to ring
Screws can enter at angles
Linear components - sk clamps, fixation pins

Question 21

Hybrid benefits

Answer 21

Minimizes morbidity by avoiding placement of wires through prominent muscle masses

Question 22

Hybrid ESF

Answer 22

Load deformation curves display linear stiffness
Biplanar fixation improves construct stability
Less stiff than circular constructs in axial and torsional

Question 23

Femoral fractures

Answer 23

Adjunctive fixation
Avoid placing pins in central diaphysis through larger muscles
Open section of ring should face caudal
Type 1B preferable