week 3:healing in bone Flashcards
what is a fracture, and the classifications?
- discontinuation of a bone
- no difference from a “break”
classifications:
- open (through skin)
- closed (within skin)
- incomplete (not complete break)
- displaced
- comminuted (bone fragments)
how do physios help with fractures?
- muscle ROM
- atrophy
- soft tissue
- ligaments
- propioception
- joint ROM
- general conditioning
what are some similarities between general healing and fracture healing?
we would expect tissue healing to take place becuase of tissues being affected as well as bone. eg.
- inflammation
- proliferative
- remodelling
what are the differences between bone and tissue healing
- bone can regenerate and fully replace injured bone
- tissue cannot
bone anatomy
define periosteum
it covers the external surface of cortical bone
define endosteum
on the inner surface facing into the medullary cavity, somtimes will have cancellous bone eg. femur
what are mesenchymal cells/osteoprogenitor cells
- dit on the endosteal and periosteal surfaces
- decompose bone and remodel bone
- they are a reserve supply of cells that action after a break
eg. chrondoblasts, osteoblasts, fibroblasts
purpose of osteoblasts
lay down bown
purpose of osteoclasts
resorb bone
purpose of fibroblasts
lay down collagen
purpose of chrondoblasts
lay down cartiliage
what are the stages of fracture healing?
- haematoma and inflammation (inflammation)
- soft callous formation (granulation tissue)
- hard callous formation
- consolidation and remodelling (remodelling)
describe the inflammatory stage
- bones bleed
- form a spindle shaped haemotoma - periosteum
- blood clots (due to the meshwork of fibrin) seals fracture site
- provides framework for inflammatory cells
at the fracture site: adjacent bone tissue dies
- bone/debris is digested and removed (increase of calcium required)
- **which releases cytokines **
- which cause proliferation of osteoprogenitor cells
- attract in growing blood cells
- can reuse excess clacium for formation of new bone
describe the soft callus stage
- osteoprogenitor cells go into haemotoma and differentiate into chrondoblasts, osteoblasts, fibroblasts, stimulated by growth factors
- invasion of cappilaries from endosteom & periosteum to continue inflammation
- ongoing desturctution of the haemotoma and debris
- laying down of collagen (fibroblasts), possible caritiliage (chrondoblasts) and early organic bone (osteoblasts)
results in a spindle shaped blob of cartilagenous, vascular and hypercellular tissue fo protection fo fracture
describe the 1st stage of hard callous process
- osteoblasts start to secrete calcium and phosphate
- forms ealry bone
- it is irregular, temporary and weak
- grows from the fratures edges across facture gaps
- forms a colar and bridge of bone
- protects fracture site
- chrondoblasts and fibroblasts are resorbed
2nd stage of the hard callous process
- 1-3months
- second wave of osteoblasts and osteoclasts(resorb bone)
- remove and relay bone
- begins to resemble normal bony architecture
- can weight bear
describe the consolidation and remodelling process
3-12 months
- vital to have forces/mobility occuring
- removal of weak areas
- lamellar bone and haversian systems (normal bone architecture)
- laying down of correctly aligned bone (osteoblasts)
what is lamellar bone
it is the bone of an adult skeleton
- can be trabecular (spongey)
- cortical (compact)
what is the haversian system?
- The Haversian canals surround blood vessels and nerve fibers throughout the bone and communicate with osteocytes
- therfere bone is very vascular
issues in fracture healing
- immobility: wither as a feature of the fracture or imposed fixation (splints)
- if the fracture is not stable, pseudeoarthrosis can occur. when two bones do not join properly and a joint is formed essentially
- deformity with bony alignment
- large fractures mean alrge bony gaps, therofre bones can heal short, therfore fixation is required to keep right length of bone
