MSK Bone Inury and Repair

zijimubo1's version from 2017-01-12 20:18

Section 1

Question Answer
T/F Bone tissue is the only connective tissue that can heal postnatally without scar.True
Name the two strict properties required for fracture healing.Adequate blood supply and mechanical stability
What is the major determinant of bone healing?Blood flow
Why(2) is mechanical stability important for bone healing?It is required for revascularization. It influences the type of healing, either indirect or direct.
Why(2) do fractures happen?Trauma- abnormal forces on normal bone; Mechanical forces(normal/load bearing forces) on structurally deficient bone secondary to disease.
Fracture healing recapitulates most events seen during what?Embryonic skeletal formation
The three stages of bone healing depend on what?The nature of the injury(degree of trauma, age, disease, co-morbidities) and method of stabilization.
What are the three stages of bone healing?Inflammatory, Repair, and Remodeling

Section 2

Question Answer
What are the main characteristics of the inflammatory stage?Formation of a fracture hematoma, an immune response, and progenitor cell recruitment and activation.
What initiates the inflammatory cascade that causes vasodilation, Local hypoxia and cell damage
How long does it take for a stable hematoma to form after a fracture?Hours
Name 4 important components found in the hematoma.Platelets PMNs(polymorphonuclear lymphocytes) Monocytes Macrophages
Platelets are important in the hematoma formed in the inflammatory stage because they are a rich source of what 3 substances?PDGF, VEGF, and TGF-beta
Name 3 important pro-inflammatory cytokines released by monocytes, macrophages, and PMNs.TNF-alpha, interleukins, and cyclooxygenase enzymes(COX-1 and COX-2)
What is an additional role of macrophages and PMNs?Remove necrotic tissue
Name 7 important growth factors that BMP WNT FGFs IGF Ihh Runx2 Osx
What releases the important growth factorsLocal periosteal cells and macrophages
How are blood vessels created throughout the hematoma?From endothelial cells that migrate from the periosteum.

Section 3

Question Answer
When does indirect bone healing (secondary healing) occur?When a fracture gap is present and in instances of less rigid fracture stabilization

Section 4

Question Answer
When does direct bone healing occur?If bone ends are in direct contact and rigidly fixed with compression plating.
What is another name for direct bone healing?Osteonal healing (primary healing)

Section 5

Question Answer
When does fracture callus remodeling begin?During the middle of the repair phase
How long does remodeling of woven bone into lamellar osteonal bone occur for?Several months to years
At what rate does lengthening occur in remodeling of DO to become biomechanically stable?1 month per centimeter of lengthening
What is remodeling?Changing woven bone into lamellar osteonal bone.

Section 6

Question Answer
Why is fracture immobilization necessary after a fracture?For revascularization of injury area to allow healing process to occur.