The review of corrosion in surgical implants in chapter 1 by Steinemann of the lnstitut Straumann is excellent. It

concentrates on the local pH changes arising from corrosion

which it is claimed can exceed the buffering capacity of

tissue fluids and lead to toxic effects. It is this type of

investigation and reasoning that leads to a better under-

standing of the fundamental aspects of biocompatibility.

From the same Institut, Pohler and Straumann present, in

chapter 6, a study of fatigue and corrosion fatigue in stainless

steel. They demonstrate with the aid of some very good

optical and scanning electron micrographs that although

the fatigue life is reduced in Ringers solution, morphologi-

cally there is no corrosion effect superimposed on the

fracture pattern.

Several of the papers dealing with ceramics are of good

scientific quality. Pabst, Wichmann and Elssner of the

Max Plank Institut, Stuttgart, in chapter 17 present data on

the fracture toughness of alumina, measuring K/,-M in four

point bending after immersion in fluids of varying polarity.

For dense alumina, KICM was found to decrease with

increasing polarity, being at its lowest for physiological

media. In the next chapter, Richter, Seidelmann and

Soltesz (Marburg, W. Germany) report on subcritical crack

growth in alumina using the double torsion method and

immersion in physiological media. Again fluids were shown

to increase crack growth rate and calculations showing the

maximum allowable flaw depth for a given lifetime are

presented. Some very interesting data on a similar theme

is also given by Dawihl and Dorne (Saarbrucken, W.

Germany, chapter 20) long-chained carboxylic acids being

shown to adsorb on alumina, completely covering the

surface with a monolayer, even at low concentration.

Adsorbed films are assumed to improve the wear and

friction properties of the material.

Amongst the papers on biocompatibility, chapter 34

on the techniques for histological examination of tissue

containing implant materials (Pesch et al., Vienna); chapter

38 on the tissue response to carbon (Helbingetal., Ulm);

chapter 43 on the histological evaluation of calcium hydroxy-

apatite (Vermeiden et a/., Amsterdam); chapter 46 on the

tissue response to alumina debris (Plenk et al., Vienna);

chapter 54 on protein adsorption on polymers (Lemm and

Unger, Berlin) and chapter 55 on in vitro culture methods

for evaluating vascular prosthetic materials (Sigot-Luizart,

Compiegne, France) are all highly recommended.

The book contains, therefore, a large number of very

good papers and is an excellent testament to the quality of

biomaterials research carried out in Europe. It is such a pity

that it took so long to produce, a fact which this reviewer

hopes will not detract too seriously from its scientific value.

David Williams

Mechanical Properties of Biomaterials Advances in Biomaterials, Volume 2

Editors G.W. Hastings and D.F. Williams John Wiley and Sons, Chichester, 1980. pp 400 Q95.00lf38.50

This book is produced from papers presented at a conference

held at Keele University in September 1978. Despite its

conference origins there is no air of improvization about

this book. The layout and presentation are of a high

standard, with clear drawings and well-reproduced photo-

graphs.

There are 48 papers from 136 contributors in it. These

are divided amongst seven sections of which five cover

aspects of orthopaedic surgery, as perhaps might be

expected when the main topic is that of mechanical properties.

The remaining sections are on general surgery and on dental

and maxillofacial surgery.

Ceramics feature strongly, not only in their special

orthopaedic section but throughout the book. This reflects

the current interest in these materials that stems from their

wear resistance, their inert nature and often a constitution

that is based on elements found naturally in the body.

Mechanical strength is the big problem with ceramics and

the papers that concentrate strongly on this aspect are

looking mainly at prostheses of part ceramic part metal

construction. The property of wear resistance features in

more of the papers, which relate to joint surfaces and teeth.

The topic of mechanical compatibility is raised in

many papers, showing a greater awareness of the importance

of this factor than was common a few years ago. There are

a number of papers concerned with porous materials or

porous coatings made from metals, ceramics and polymers:

the inclusion of one on polysulphone introduces a relatively

new implant material. Carbon has created much attention

in its solid form, as coatings, as fibrous reinforcement for

UHMWPE bearing surfaces and for structural composite

materials. Calcium hydroxyapatite accounts for a run of

four papers presented by authors from five countries.

There are a fair number of unusual materials investi-

gated; including glass ceramics, nitride ceramics and plasma

sprayed ceramic coatings. Crosslinked gelatine has two

papers describing its successful use as a resorbable material

for repair of ureters and urethras and for use in hip joint

surgery. Another two papers report successful work on bone

defect bridging by porous formers of elastomer/textile

construction to carry autologous bone chips and defect

filling by collagen fleece.

Apart from novel devices and materials there is much

work reporting clinically-proven improvements from design

and materials developments in well established devices such

as total hip prostheses. In the same group there is extra

future potential being developed by such techniques as hot

isostatic pressing as an alternative to casting or forging of

Co/Cr/Mo alloys. Acrylic cement gets its usual mentions

including two papers on the modification of fracture

behaviour by X-ray contrast materials.

With others, these topics go to make up the 48

papers presented. They contain much worthwhile informa-

tion and the presentation is good.

G. Murray

Biomaterials 198 1, Vol2 July 191