Cements as bone repair materials - Bone Repair Biomaterials - page 294

the effectiveness of the cement to act as carrier for drug delivery in vivo , must
be assessed. And finally, the clinical performance of the drug delivery system
must be evaluated. Up to the present time, the first three aspects have been
extensively studied, but the application of CPCs as drug delivery systems
has not yet reached clinical application. Major attention has been paid to
antibiotics, owing to their wide areas of application: either as prophylactics
to prevent infections produced during surgical interventions, or in general in
the treatment of bone infections. Other types of drugs incorporated in cements
include anti-inflammatory drugs, anticancer drugs and even hormones have
been studied. In recent years the inclusion of growth factors that are able to
stimulate bone regeneration, such as bone morphogenetic proteins (BMP) or
transforming growth factors b (TGF-b) have been considered for controlled
delivery from CPCs. 189
Although the research carried out to date has shown the great potential of
CPCs as carriers for controlled release and vectoring of drugs, the industrial
use of CPCs for drug delivery is not yet a reality. Two main causes can be
identified. First, implant companies selling CPCs do not generally have the
know how to deal with drugs and pharmaceutical companies do not have
any know how about CPCs. Second, the infections are not always produced
by the same microorganisms and, therefore, it would be necessary to design
versatile systems, which could combine a given CPC with many different
drugs, in a way that the surgeon could choose the drug just before implantation.
Since various drugs have various effects on CPC properties, this represents
a serious drawback for technology implementation. Therefore, much work
still has to be done to be able to obtain reproducible and predictable systems
and to adjust the use of CPCs to different therapeutical needs.

10.5 References
1. Charnley J 'Anchorage of the femoral head prosthesis to the shaft of the femur',
J Bone Joint Surg , 1964, 42B , 28.
2. Charnley J 'Bonding of prosthesis to bone by cement', J Bone Joint Surg , 1964,
46B , 518.
3. Charnley J Acrylic Cement in Orthopaedic Surgery , E & S Livingstone, London,
1970.
4. Kühn KD Bone Cements , Springer Verlag, Berlin Heidelberg, Germany, 2000.
5. Lewis G 'injectable bone cements for use in vertebroplasty and kyphoplasty:
state-of-the-art review', J Biomed Mater Res Part B: Appl Biomater , 2006, 76B ,
456-68.
6. Hernández L, Gurruchaga M and Goñi I 'Injectable acrylic bone cements for
vertebroplasty based on a radiopaque hydroxyapatite. Formulation and rheological
behavior', J Mater Sci: Mater Med , 2009, 20 , 89-97.

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7. LeGeros r, Chohayeb a and Shulman a 'apatitic calcium phosphates: possible

dental restorative materials', J Dent Res , 1982, 61 , 343.