REPORT OF UK BIOMATERIALS MEETING, IMPERIAL COLLEGE (HAMMERSMITH HOSPITAL), 17
NOVEMBER 1999
The full day meeting consisted of a morning session
considering "Clinical Views on Biomaterials" followed by an informal
afternoon networking opportunity.
The first presentation discussed the current status of
biomaterial research in orthopaedic surgery (McCarthy, IC). Consideration was
given to the current thinking relating to the need for approximately 40%
revisions of hip/shoulder (total numbers 80,000 in UK) and knee (40,000 in UK)
replacements. Wear particle debris
was demonstrated for alloy, polymer and ceramic materials as was the more recent
concept of nitrogen oxide (NO) radical formation leading to inflammatory
activity (at the bone/cement interface) and consequent failure of the
replacement function. New metal/metal, ceramic/ceramic and isoelastic materials
were not believed to be sufficiently promising. However porous surfaces/coatings
(e.g. hydroxyapatite) were favoured, even though there was acknowledgement of
concerns as to the likely long-term success of some such material in certain
applications. A general overview of the recent Brite-EuRam intervertebral spacer
project was presented, although there was a feeling put forward that poor
nutrition of the natural disc (which leads to its failure) may also affect any
implanted material. The requirement for replacement cartilage materials (beyond
autologous seeding of chondrocytes to polyester/graphite) and new internal
fixation glues/devices completed the presentation.
The second presentation considering "Contact
Activation of Humeral and Cellular Blood Components (Asimakopoulos, IC), whilst
interesting for the purpose of a cross-sector "teach-in", only really
presented a text book overview of the issues.
The third presentation on "Maxillofacial Materials”
(Fisher, Nottingham) highlighted the challenges facing the need for
reconstruction of approximately 60% of the 500,000 (1997) facial
injury/congenital defect cases in the UK. The difficulties in overcoming the
variation in bone and soft tissue formation, stress/load bearing tissues, and
facial contours were presented through interesting clinical cases. The lack of
total resorption of some current materials (e.g. polylactic acid, PLA) and
particulate migration of others (e.g. polyethylene, PE) was demonstrated. The
concept of new materials with varying properties depending on application (e.g.
PE-HA and caprolactam) was discussed.
Last, but by no means least, was the dual presentation of
Polak and Hench (IC) entitled "Overview of the Current Status of Tissue
Engineering". Although not really achieving the title, the concept of
regeneration of engineered or bioactive materials (rather than current tissue
replacement and past tissue removal approaches) was discussed through the
example of a sol-gel (microporous) Bioglass. This material was shown to support
cell growth, osteocalcin synthesis, bone nodule formation and collagen matrix
deposition. Combined with micromechanical stimuli, simple seeded scaffolds were
shown to lead to differentiated cells, although the need for much greater
insight into extracellular matrix deposition with biomechanical properties was
acknowledged.
The informal network session saw presentation of a report
from the recent EU MATMED meeting and a short presentation from the UK EPSRC
manager as to the potential role for UK Biomaterial participants in these
projects/programmes.
Despite some interesting technical presentations, there
must remain reservations as to the network's real long-term success without some
form of re-assessment of its identity/purpose. Whilst possibly a one-off with
regard to the topics chosen, the network was not particularly well attended
either by academics or industrialists, thereby showing signs of its initial
impetus stalling. The very low number of industrial participants in attendance
created few networking opportunities and little industrial focus and the meeting
broke early. This was despite a reported increase in interest in the network
itself. Nonetheless, its future is in its own hands and that is always a good
place to have it.
Dr J BRAYBROOK
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