Bone injuries Flashcards
Describe the process of bone growth?
The bone collar develops to from a periosteum inside the bone.This is the primary ossification centre.
Blood vessels then start to form and the secondary ossification centres
The medullary cavity forms within the bone. The epiphyseal plates form at either end and the articular cartilage develops around the bones.
Perioesteum and compact bone form within the shaft of the bone
What is:
The diaphysis Metaphysis Epiphysis Physis Medullary canal
The diaphysis- shaft
Metaphysis- flare at end of shaft
Epiphysis- on the joint side of the physis
Physis - growth plate- cant put nail in these, cause abnormal growth
Medullary canal- central cavityof bone shafts where red bone marrow and/or yellow bone marrow is stored
What is cortical bone?
Dense outer surface of bone that forms a protective layer around the internal cavity. Also known as compact bone this makes up 80% of skeletal mass. Contains osetons and haversian canals. resists bednign and torsion, less biologically active
What is cancellous bone?
spongy or trabecular bone is is very porous and contains red bone marrrow where red blood cells are made.. Weaker and easier to fracture, resists bone absorbtion and compression. Site of longitudinal growth
What is a fracture
Break in structural continuity of the bone May be a crack, break, split, crumpling or buckle # is shorthand for fracture
When do bones fail
High energy transfer in normal bones.Takes a lot of effort.
Repetitive stress can lead to a stress fracture
Low energy trasfew in abnormal bones:
Osteoperosis
Osteomalacia
Metastatic tumour
What is stage 1 in the fracture process
Inflammation begins immediately after fracture. Heamatoma anf fibrin clot.Bi-products of cell death
Fibroblasts, Osteoprogentor cells are present
Angiogenesis occurs, patients are splinted for correct healing
What is stage 2 in the fracture process
soft callus begins when pain and swelling subside Lasts until bony fragments are united by cartilage or fibrous tissue Some stability of a fracture Angulation can still occur Continued increase in vascularity May need bone graft
What is the ideal bone graft
Autogenous cancellous bone graft
Gold standard
Osteoinductive
What is stage 3 in the fracture process
hard callus- conversion of cartilage to woven bone
Typical long bone fracture, endochondral bone formation, membranous bone formation
Causes increasing rigidity
What is stage 4 in the fracture process
Bone remodeling
Conversion of woven bone to lamellar bone
Medullary canal is recosntitued
Bone responds to loading characteristics
What is a strain fracture?
The % change of intial dimensions
If strain is low mechanical induction of tissue differentiation fails
What is delayed union?
Failure to heal in expected time, this can be due to: High energy injury Increased osteogenic jumping Instability Infection Steroids Immune suppresants Smoking Warfarin NSAIDS Ciprofloxacin (antibiotic, bad for MSK)
What is non union?
failure to heal failure for calcification fibrocartilage forms instability (excssive osteoclasts) Abundant callus formation Cause pain and tenderness Persistant fracture line Sclerosis
What should be considered in delayed healing?
different fixation
Dynamisation
Bone grafting
