- Slower incorporation due to need to remodel existing Haversion canals- Interstitial lamellae preserved- Provides more structural support- 25% of massive grafts sustain insufficiency fractures
Calcium phosphate grafts
- Osteoconductive - Quick resorption - Examples include: OsteoSet (Wright medical)
see Rank-L and Bone Growth Factors
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You are considering using a frozen allograft distal femoral condyle in your reconstruction of a massive giant-cell tumor of the knee. In counseling your patient regarding the risks of allografts, you explain that 5 years after transplantation, what percentage of donor chondrocytes will be present and viable in the allograft?
greater than 50%
None, by 5 years the allograft cartilage will be completely acellular
Select Answer to see Preferred Response
Storage of musculoskeletal allografts by cryopreservation is achieved by
replacing water in the tissue with alcohol to a moisture level of 5% and then using a vacuum process to remove the alcohol from the tissue.
maintaining maximum cellular viability of fresh tissue without long-term storage.
using chemicals to remove cellular water and controlled rate freezing to prevent ice crystal formation.
freezing the graft twice and packaging the tissue without solution at minus 80 degrees C.
freezing the graft in water without an antibiotic solution soak during quarantine, with final storage in liquid nitrogen.
Which of the following factors is most critical to the success of a meniscal allograft transplantation?
Accurate graft size
Donor cell viability
Reestablishment of the central meniscal blood supply
Suppression of the immune response
Cryopreservation of the donor graft
You are planning surgery on a 54-year-old female with the tibial plateau fracture seen in figures A and B. After reduction of the joint surface you plan to fill the void with a bone-graft substitute to prevent joint collapse. Which of the following bone-graft substitutes disappears most quickly in vivo?
Synthetic calcium sulfate and tri-phosphate mixture
Which of the following bone graft material contains live mesenchymal osteoblastic precursor cells?
Fresh-frozen allograft bone
Recombinant bone morphogenic protein
Demineralized bone matrix
Autologous iliac crest marrow aspirate
Calcium phosphate putty
Iliac crest cancellous bone graft can be harvested from either the anterior or posterior aspect of the pelvis. When comparing these two locations, harvesting from the anterior iliac crest has which of the following?
Less severe postoperative pain at the surgical site
Decreased postoperative gait abnormalities
Increased complication rates as compared to posterior harvesting
Decreased postoperative pain duration
Increased cancellous bone graft density
Which of the following groups correctly identifies serologic tests that are required by the American Association of Tissue Banks (AATB) for musculoskeletal tissue allografts?
Cytomegalovirus, Hepatitis A, Hepatitis B, Hepatitis C, HIV, Syphillis
Cytomegalovirus, Hepatitis A, Hepatitis B, Hepatitis C, HIV
Hepatitis A, Hepatitis B, Hepatitis C, HIV, Syphillis
Hepatitis B, Hepatitis C, HIV, Syphillis
Hepatitis B, Hepatitis C, HIV
Which of the following is true of both calcium phosphate and calcium sulfate?
They have high resistance to shear forces
They have high resistance to torsional forces
They are contraindicated in spinal fusion
They provide a scaffold for bone progenitor cells
They are not biocompatible with stainless steel orthopedic implants
Which of the following bone graft substitutes has the fastest resorption characteristics?
Cortical iliac crest autograft
Which of the following graft materials has the least potential to elicit an immune response?
Fresh irradiated corticocancellous bulk allograft
Fresh frozen fibular strut allograft
Fresh frozen Achilles tendon allograft
Fresh Achilles tendon allograft
Freeze dried cancellous bone chips
A 20-year-old male is involved in motor vehicle collision and sustains a depressed tibial plateau fracture. When performing surgery, if calcium sulfate is used as the primary bone substitute void filler, an increase in which of the following outcomes may be expected as compared to autograft?
Increased complications due to serous drainage
Improved clinical outcomes as shown by more rapid time to healing
Improved clinical outcomes as shown by SF-36 scores
Increased complications due to autoimmune reactions and graft rejection
Equivalent complication rates and clinical outcomes
What is the approximate risk of transmission of HIV in fresh-frozen allograft bone?
1 in 10,000,000
1 in 1,000,000
1 in 100,000
1 in 50,000
1 in 10,000
Which of the following substances is most osteoinductive?
Xenograft collagen sheet
Which of the following osteoconductive bone graft substitutes resorbs faster than the rate at which bone growth occurs?
Collagen-based matrix with hydroxyapatitie coating