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Bone Grafts / Bone Graft Substitutes
Bone healing stages: Impact > Induction > Inflammation > Soft callus(5-21days) > Hard callus > Remodeling.
Vascular Phases of Bone repair:
- Phase I: 0-1wk: reduction in blood flow
- Phase II: 1-4 weeks increased blood flow
- Phase III: 5-8 weeks returns normal
Positive Bone Healing Factors
- High vascular fracture areas
- Increased bone surface area
- Mechanical stability
- Mechanical loading
- Bone Growth Factors (BMP 2,3,6,7,9)
Negative Bone Healing Factors
- Smoking (nicotine, and decreased oxygenation)
- Diabetes
- Radiation
- Tumors
- Mechanical instability
- Infection
- Corticosterioids
- Chemotherapy
- Malnutrition
- Metabolic bone disease
- NSAIDs
- HIV
Calcaneous Chips
- 5- to 7-mm freeze-dried cancellous chips
- Limited structural support; osteoconductive and limited osteoinductive
Corticocancellous bone segments
- May be cut to shape/size/fill segmental defects
- High structural support, osteoinductive
- Disease potential; immunogenicity; slow incorporation
Distal Tibia
Iliac Crest Autograft
- Gold standard
- Osteoconductive, osteogenic. Minimal active BMPs.
- Complications: acute/chronic donor site pain, infection, fracture, hematoma (Arrington ED, CORR 1996;329:300)
- Ebraheim NA, JAAOS 2001;9:210
Proximal Tibia
Allograft
Platelet Concentrates / Autologous Growth Factor (AGF)
- Rich in platelet-derive growth factor, TGF-B,
- Has not been shown to be beneficial in spinal fusion (Weiner BK, Spine 2003;28:1968)
Growth and Differentiation Factor 5
- Synonms: MP-52, LAP-4, CDMP-1, BMP-14, Radotermin, Healos/rhGDF-5
- 100% fusion rate in rabbits (Magit DP, Spine 2006:31:2180).
- Further human research needed
Ultrasound
Calcium Phosphate
- Injectable through minimal incision
- High compressive strength
- Not osteoconductive or inductive
- Slow reabsorbtion, limited shear or tensile strength
Calcium sulfate
- Pellets, paste, putty
- Injectable through minimal incision; may be combined with antibiotics
- Minimal structural support, water-soluble, rapid resorption
Hydroxyapatite
- Slowly degradable ceramic
- Animal studies demonstrate increased fixation strength, no clear clinic advantage.
- Can be shaped to fill defect
- Slow resorption
Tricalcium Phosphate
- Synonyms: beta-tricalcium phosphate
- Osteoconductive. Osteogenic and inductive when mixed with marrow aspirate.
- Minimal to no structural support, variable rapid resorption rates
- Trade names: Vitoss, Orthovita, Malvern, PA
Demineralized Bone Matrix (DBM)
Bone Morphogenetic Proteins (BMPs)
- Low molecular weight noncollagenous glycoproteins; part of TGF-beta superfamily.
- rhBMP-2 (Infuse-Metronic) has shown clinical utility in spinal fusion (Glassman SD, Spine 2005;30:1694) and tibial fractures (Swiontkowski MF, JBJS 2006;88A:1258).
- BMP-7 (OP-1-Stryker): has shown clinical utlity in spinal fusion (Vaccaro AR, Spine 2005;30:2709) and tibial nonunions (Friedlaender AR, JBJS 2001;83A(suppl 1):s151).
Bone Marrow Aspirate
- Bone marrow is aspirated from both anterior iliac crests, concentrated on a cell separator, and then injected percutaneously.
- 88% helaing rate in atrophic tibial nonuions. (Hernigjou P, JBJS 2005;87A:1430).
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