Biomedical Engineering Reference
In-Depth Information
bridgethedefectwithinthreemonths,whilethetreatmentofempty
scaffolds led to the nonunion of the critical-sized defect. Thus, this
BTEstrategydemonstratedagreatpotentialforclinicalapplications.
43.3.3
The Use of Scaffolds with or without Growth
Factors and Cells for Clinical Trials
There have been several clinical trials using stem cells with or with-
outscaffoldsfornewboneformation.Kitoh
et al
.describedthatthey
could reduce the consolidation time of new bone after injection of
culture-expanded BM stem cells with PRP as a scaffold into the dis-
traction area in 17 patients. The healing index was 25 days per cen-
timeter in the cell injection group, whereas the healing index was
36 days per centimeter in the control group. This method improved
vascularinvasionfromsurroundingmuscletissuesatthesiteofdis-
traction. The area without a su
cient vascular bed is not an ideal
site for injection, such as the anteromedial aspect of the tibia. This
method has the advantage of no limitation of the donor site com-
pared with autografting because it is possible to keep a large num-
berofviablecellsduringtreatment.Thedisadvantageisthatittakes
four to six weeks for culturing stem cells before injection and sec-
ondary surgery is necessary.
Marcacci
et al
. tried to use stem cells with macroporous bio-
ceramics for treatment of long bone defects in four patients. The
age of patients ranged from 16 years to 41 years, and the sizes of
bone defects ranged from 4 to 7 cm. External fixations were applied
for stability. After six to seven years' follow-up, they found that
there were no late fatigue fractures of the bioceramic implants, and
there wasboneunionbetweentheceramicsandthehostbone.This
methodhasthedi
cultyofevaluationofnewboneformationinside
theceramicsbecausetheceramicsarevisibleasradio-opaquemate-
rials on radiographs and the calluscould not bevisible.
Jones
et al
. performed a randomized, controlled clinical trial
using BMP-2 mixed with an allograft for reconstruction of a diaphy-
seal tibial fracture with cortical defects and compared the effect of
this method with autogenous bone graft. The mean of bone defect
length was 4 cm, ranging from 1 to 7 cm. They found that 87% of
BMP-2 with the allograft group obtained fracture healing, whereas
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