Bone Growth and Fracture Healing Flashcards
Cortical bone is located where?
Diaphysis of bone
Cortical bone resists what?
Bending
Torsion
Cancellous bone resists what?
Compression
What type of bone is most biologically active?
Cancellous bone
Why do bones fail?
High energy transfer (normal bones)
Repetitive stress in normal bones
Low energy in abnormal bones
What are the stages of fracture repair?
1 - Inflammation
2 - Soft callus
3 - Hard callus
4 - Bone remodelling
What is the inflammatory stage of fracture repair?
Hematoma + clots
Platelets, WBC
Fibroblasts
Angiogenesis
What is the soft callus stage of fracture repair?
Starts after pain/swelling subsides
Until bony fragments united
Some stability
Increased vascularity
What is the best bone graft?
Autogenous Cancellous bone graft
What is the hard callus stage of fracture repair?
Cartilage -> woven bone
Increased rigidity
What is the bone remodelling stage of fracture repair?
Conversion of woven bone -> lamellar bone
Medullary canal reconstituted
What is delayed union?
Failure to heal in expected time
What are the potential causes of delayed union?
High energy injury Distraction Instability Infection Steroids Immune suppressants Smoking Warfarin NSAIDS
What is non-union?
Failure to heal
What are the alternative managements in delayed healing?
Different fixation
Dynamisation
Bone grafting
