Fracture biology Flashcards
What are the two micostructural levels of bone?
Woven bone and lamellar bone. Microstructure can also be described using the differentiation of primary bone (primary lamellar bone, primary osteons) v secondary bone (secondary osteons formed during remodelling).
What are the macrostructural levels of bone?
Cortical bone, cancellous bone.
What is the porosity of cancellous bone and cortical bone?
Cortical bone: 5%
Cancellous bone: 60-75%
What are the four functional bone envelopes?
Periosteal: Inner lining is cell rich (cambrium) with osteoprogenitor cells. Can form lamellar or woven bone.
Endocortical: Lined with lining cells that regular calcium exchange.
Cancellous: Similar to endocortical envelope but on trabecular struts. Involved in nutrient and ion exchance.
Intracortical: Cells lining the Haversian canal help to regulate nutrient exchange.
What are the two mechanisms of bone formation during skeletal development?
Intramembranous and endochondral ossification
Describe the process of intramembranous ossification
Describe the process of endochondral ossification
Describe the 5 layers of the physis
See page 634 Tobias for more in depth description
Describe the 5 different configurations of Salter Harris fracture
Describe the forces associated with various fracture configurations
See Tobias page 639 for more in depth description
What are the strain tolerances of various tissue types in the healing bone?
Granulation tissue: 100%
Fibrocartilage: 10-15%
Bone: 2%
What are the two types of bone healing that may be observed following fracture?
Primary/direct bone healing (contact and gap), secondary/indirect bone healing
What are the conditions for contact and gap healing to occur?
Contact: <0.01mm gap, functional elimination of strain
Gap: <1mm, functional elimination of strain
What are the five stages of secondary bone healing?
Inflammation
Intramembranous ossification
Soft callus formation
Hard callus formation
Bone remodelling
