Biphasic calcium phosphate ceramics in small bone defects: potential influence of carrier substances and bone marrow on bone regeneration.
OBJECTIVE
Synthetic calcium phosphate bone substitutes such as hydroxyapatite (HA), beta-tricalcium phosphate (beta-TCP) or mixtures are alternatives to autogenous bone grafts. TricOs T((R)) and Collagraft((R)) are resorbable bone substitutes consisting of biphasic calcium phosphate and a bioactive matrix. Both products have a similar HA to beta-TCP ratio, but differ by their matrix. It was the aim of this study to determine the influence of matrix and autologous bone marrow on bone regeneration in a rabbit femoral condyle model.


METHODS
A critical-sized bicortical channel with a diameter of 4.5 mm was drilled through the femoral condyles in male New Zealand rabbits. Collagraft((R)) with bone marrow harvested from the posterior iliac crest or TricOs T((R)) with and without bone marrow was introduced into the defect. Rabbits were euthanized 8 weeks later. The percentage of newly formed bone was determined by micro-computed tomography.


RESULTS
There was no significant difference between bone ingrowth at 8 weeks. Thus, TricOs T((R)) without bone marrow showed similar bone ingrowth as Collagraft((R)) with bone marrow. Furthermore, no increase of bone ingrowth could be achieved by adding bone marrow to TricOs T((R)) in the present setting.


CONCLUSIONS
Both bone substitutes showed similar bone ingrowth in this investigation. Using TricOs T((R)) without bone marrow could avoid donor site morbidity due to harvesting of bone marrow. Further prospective clinical trials will be needed to investigate this approach.
Castellani
C
C
Department of Paediatric Surgery, Medical University Graz, Graz, Austria. christoph.castellani@medunigraz.at
Zanoni
G
G
Tangl
S
S
van Griensven
M
M
Redl
H
H
D000818:Animals; D001853:Bone Marrow / Q000187:drug effects*; D001857:Bone Matrix / Q000637:transplantation; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000494:pharmacology*; D003094:Collagen / Q000494:pharmacology*; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D011446:Prospective Studies; D011817:Rabbits; D014945:Wound Healing / Q000187:drug effects; D055114:X-Ray Microtomography
D018786:Bone Substitutes; D002130:Calcium Phosphates; C549165:TricOs T; C065819:Collagraft; D003094:Collagen; C485829:calcium phosphate, dibasic, anhydrous