Fracture Repair Flashcards
(44 cards)
What two types of fracture healing can there be?
1) Indirect 2ndry - Natural, Callus formation.
2) Direct 1ry - Normally requires surgical intervention.
Outline the steps in Indirect Fracture Healing - Sequence of Increasing Stiffness
Inflammation, Haematoma, Granulation tissue, Connective Tissue, Fibrocartilage and cancellous bone, Bone.
When are growth factors released in fracture healing? What do they do?
Growth factors are released immediately. It is also further released when the bone ends get resorbed.
In callus formation, what is important when going from haematoma to callus?
Tissues have an increasing need for oxygen tension, and also more complex tissues need less movement to form.
What size gap in a fracture will cause indirect healing?
Anything >1mm
What size gap in a fracture will cause direct CONTACT healing?
Fragments have to be in contact with a tiny (<0.01mm) gap
What size gap in a fracture will cause direct GAP healing?
Fracture has to be <1mm
Which of the 3 fracture healing possibilities will tolerate some movement, and which will tolerate none?
Indirect tolerates some, both direct will not tolerate any.
What two categories can Direct (Primary) healing be split into?
Contact healing and Gap healing.
What is the difference between Contact healing and Gap healing?
Contact healing requires a smaller gap, and the fragments have to be in contact.
How does Direct Contact healing work?
Direct migration of Osteones (haversian system) over the fracture line.
How does Direct Gap healing work?
Layered bone forms across fracture gap. They are weak. Osteones can then cross the fracture gap.
Which of direct or indirect is weaker? Which takes longer?
Direct unions are weaker, and usually take longer.
What is a Malunion in fracture healing?
Bone unites correctly but in the wrong position.
What is a Non-union in fracture healing?
Failure or delay in bone healing.
What is a Viable and Non-viable Non union?
1) Viable - Physiology still works. Healing is happening but may be too slow etc.
2) Non viable - Healing is not occuring.
Where is a diaphyseal fracture?
In the middle of a long bone.
What are the most important forces acting on a diaphyseal fracture?
Compression, Tension, Shear and Torsion.
What are some problems associated with Co-aptation of a Diaphyseal fracture?
Gives little stability, can result in fracture malalignment, cannot apply to fractures proximal to stifle/elbow.
What different ‘modes’ can implants take in fracture repair? Explain them.
Compression - squeezes fracture together, Neutralisation - resconstruct fracture, used to protect. Buttress - Implant takes all forces.
What three implant systems can be used in diaphyseal fractures?
Plates and Screws, External Skeletal Fixator or the Interlocking Nail.
What does the External Skeletal Fixator (ESF) consist of?
Pins driven into bone that exit the skin, clamps connecting pin and connecting bar. Connecting bar runs length of bone. Normally indirect bone healing.
What are the advantages and disadvantages of ESF?
Adv - Quick, relatively cheap, can do ‘closed’, can be adjusted. Disadv - Pins can loosen, difficult to compress.
How do plates and screws work?
Metal plates attached to either side of the fracture with bone screws. Generate primary or secondary bone union.
