Fracture Healing Flashcards
What are the functions of bone?
Support, protection and movement Mineral storage (calcium and phosphate)
What type of bone makes up the majority of the skeleton?
Cortical bone
Describe the features of cortical bone?
Slower turnover rate and metabolic activity
High Young’s modulus and resistance to torsion and bending
Describe the features of cancellous bone?
Higher turnover rate
Undergoes greater remodelling
Lower Young’s modulus and is correspondingly more elastic
What components make up the matrix portion of. bone?
Collagen
Non-collagenous proteins
Mucopolysaccharides
Calcium Phosphorous
What cells are present in bone?
Osteoprogenitor cells
Osteocytes
Osteoblasts
Osteoclasts
What is the name for the shaft of the bone?
Diaphysis
What is the name for the end of the bone?
Epiphysis
What is the name for the mid region of the bone between the end and the shaft?
Metaphysic
What is the other name for the growth plate of a bone?
Physis
What is the function of the physis?
Responsible for skeletal growth and allows remodelling of angular deformities after fracture
What is the result of damage to the physeal blood supply?
Growth arrest which can be partial or complete
Indirect healing is an artificial situation. T/F?
False - direct healing is an artificial situation
What is indirect fracture healing?
Formation of bone via a process of differential tissue formation until skeletal continuity is restored
How long after fracture does a haematoma form?
6-8 hours
For how long in fracture healing does the soft callus persist?
3 weeks
What are the steps in indirect fracture healing?
Formation of fracture haematoma
Fibrocartilaginous callus formation
Bony callus formation
Remodelling
For how long in fracture healing does the bony callus persist?
3-4 months
Which cells lay down woven bone in the process of bony callus formation in fracture healing?
Osteoblasts
Describe the formation of the soft callus in fracture healing?
New capillaries organise the fracture haematoma into granulation tissue which is a pro callus. fibroblasts and osteogenic cells then invade the pro callus and make collagen fibres which connect the ends together. Chondrocytes then begin to produce fibrin cartilage and the soft callus forms.
What is direct fracture healing?
An artificial surgical situation in which there is direct formation of bone withthout the process of callus formation to restore skeletal continuity.
Describe the process of direct fracture healing
No callus forms and there is direct formation of bone via osteoclastic absorption and osteoblastic formation (cutting cones)
Cutting cones cross the fracture site and lay down new osteones directly
What vessels supply the inner two thirds of a bone?
Endosteal vessels
What vessels supply the outer third of a bone?
Periosteal vessels
Fractures at what sites are particularly prone to problems with union or necrosis because of potential problems with blood supply?
Proximal pole of scaphoid
Talar neck
Intracapsular hip
Surgical neck of humerus
What patient factors can inhibit fracture healing?
Increasing age Diabetes Anaemia Malnutrition Peripheral vascular disease Hypothyroidism Smoking Alcohol
Which medications can inhibit fracture healing?
NSAIDs
Steroids
Bisphosphonates
How to NSAIDs inhibit fracture healing?
reduce local vascularity at fracture site
COX-2 specific NSAIDs inhibit fracture healing more than non-specific NSAIDs. T/F?
True
