Bone Grafting

Question 1

What graft substitute has the fastest absorptive rate?

Answer 1

Calcium sulfate>tricalcium phosphate>hydroxyapatite
Are all osteoconductive
Calcium sulfate resorbs in 4-12 weeks

Question 2

5 years after implantation of articular cartilage allograft, what percentage of chondrocytes remain?

Answer 2

0%

Question 3

Define and give examples of osteoconductive, osteoinductive and osteogenic substances?

Answer 3

1) Osteoconductive- gives structural framework for bone formation (e.g. DBM, hydroxyapatite, calcium sulfate)
2) Osteoinductive- contains factors that promote bone formation and induction of stem cells (e.g. BMP)
3) Osteogenic- contains actual osteoprogenitor cells (e.g. iliac crest aspirate)

Question 4

Which type of allograft has highest risk of immunogenicity and disease transmission?

Answer 4

Fresh
Fresh frozen less so and is still osteoinductive
Freeze dried is least immunogenic but is not osteoinductive (BMP is depleted)

Question 5

What type of graft growth characteristics does DBM possess?

Answer 5

Osteoconductive and osteoinductive

Question 6

Which synthetic graft substitute has the highest compressive strength?

Answer 6

Calcium phosphate

e.g. Norian-tricalcium phosphate

Question 7

Calcium phosphate bone substitutes have been shown to allow for bone defect filling, early rehabilitation, and prevention of articular subsidence in what type of fractures?

Answer 7

Distal radius and tibial plateau

Question 8

In fresh frozen allografts what is the disease transmission rate of HBV, HCV and HIV?

Answer 8

Hepatitis B- 1:63,000
Hepatitis C- 1:100,000
HIV- 1:1,000,000
Fresh frozen tested for HBV, HCV, HIV, syphillis, and HTLV-1

Question 9

if calcium sulfate is used as the primary bone substitute void filler, an increase in what outcomes may be expected as compared to autograft?

Answer 9

increased wound drainage