SL1 - Bone Healing Flashcards
bone is composed of
minerals - Ca, P, Mg
Organic Matrix - type I collagen, proteoglycans, glycosaminoglycans
T/F there is separate venous drainage for cortex and medullary canal
true
osteoblasts
produce osteoid (unnmineralized bone matrix) on bone surface
osteocytes
osteoblasts that have been encased in mineral matrix
maintain bone matrix
osteoclasts
active in areas of bone remodeling
reside near bone surface
what are the 3 phases of bone healing
inflammation phase
repairative phase
remodeling phase
inflammatory phase
lasts about 2-3 weeks
death of osteocytes results in release of lysosomal enzymes
necrotic material at site of the fracture is source of inflammatory respose
repair phase
migration of osteoprogenitor cells - forms periosteal callus
angiogenesis - transient blood supply from surrounding soft tissue
deposition of Ca hydroxyapatite in matrix - callus mineralization
cartilage replaced by bone via endochondral ossification
remodeling phase
begins when fracture is bridged by callus
woven bone remodeled into lamellar bone via osteoclasts and osteoblasts
remodeling phase is directed by ______
stresses of weight bearing
types of bone healing
primary/direct
secondary/indirect
contact healing
primary bone healing
occurs with compression of bone ends under rigid fixation
no cartilaginous callus formed
gap healing
gap between fracture ends is < 1mm
granulation tissue at gap followed by transversely oriented lamellar bone
haversian remodeling occurs at ~ 3 weeks post stabilization
T/F primary bone healing outmoded in favor of secondary bone healing
True
exceptions: articular fractures and simple, stable fractures
secondary bone healing
fracture ends dont touch
micromotion at fracture promotes formation of callus
bone heals via mineralization of fibrocartilagenous callus into boney callus
