TISSUE REACTIONS TO POLYTETRAFLUORETHYLENE

1379 TISSUE REACTIONS TO POLYTETRAFLUORETHYLENE

SIR,-Surgeons, and especially orthopxdic

surgeons,

should be warned that tissue reactions are likely to follow the implantation of polytetrafluorethylene (P.T.F.E., ’Teflon ’,‘ Fluon ’) if this material is subjected to abrasion, and that these reactions may not be manifest for

two

polyethylene (not necessarily ordinary polyethylene [’Polythene’]) does not produce any tissue reaction when implanted in a finely divided state. Wrightington Hospital, JOHN CHARNLEY. near Wigan.

years.

insufficient attention seems to have been paid to P.T.F.E. in finely divided form. After pioneering its use in arthroplasty I abandoned it over two and a half years ago, and I write this because I have been told that a firm which distributes this material is still having frequent requests to supply P.T.F.E. to orthopxdic surgeons in sheet form for insertion between the femur and the tibia as an arthroplasty of the knee. This simple, and therefore attractive, operation was announced at the spring meeting of the British Orthopaedic Association of Sheffield, and I attended the meeting especially to issue a word of warning in the discussion; but, ironically, the chairman vetoed discussion on the grounds of lack of time! It is unlikely that the paper on this subject which I am engaged on at present will be in print before another two years In

warning against the use of P.T.F.E. where abrasion with the liberation of particles is likely; and (2) to indicate that there are grounds for believing that " high-density "

biological

IMMUNOLOGICAL PREGNANCY TESTS

tests

have elapsed. Particles of abraded P.T.F.E. (easily revealed by polarised rise to an intense foreign-body reaction. Granulomatous masses form, and sometimes break down internally and produce collections of sterile " pus ". Masses of amorphous white debris accumulate which can truly be called caseous and often reach 100-200 ml. in volume. Chemical analysis shows that by dry weight it contains about 13% of P.T.F.E. In contact with bone this caseous material is slowly erosive, because no fibrous reaction seals it off from bone. But in contact with soft tissues it becomes clearly encapsulated. This behaviour is identical with what happens in bone and joint tuberculosis, and I am sure this artificial granuloma will yield valuable information on the nature of the tuberculous process. Fortunately, surgical removal and curettage results in complete healing without sinus formation, and in this, unlike tuberculosis, the treatment of the P.T.F.E.-granuloma is quite reliable. I think that tissue reaction to P.T.F.E. is partly the result of persistent mechanical movement between the main mass of the implant and the bone, and in part a chemical reaction produced by the abraded particles. I have had introduced subcutaneously into my thigh, by means of a wide-bore needle and trocar, two specimens of P.T.F.E. and one specimen of high-density " polyethylene, prepared in finely divided form. After nine months in situ the two P.T.F.E. specimens are clearly palpable as nodules, and have been stationary in size for the last six months. They are almost twice the volume of the original implant. The " high-density " polyethylene cannot with certainty be detected by palpation, which I take to indicate that no tissue reaction has been produced by this material in finely divided form. Twenty-four hours after insertion I had an unpleasant systemic reaction, with consciousness of my heart-beat (though without a rise in pulserate), which lasted twenty-four hours, and this was followed by tenderness and redness of the skin overlying both the P.T.F.E. specimens, persisting for about three days and disappearing within the week. At no time was there any tenderness or redness of the subcutaneous tissue related to the implant of

light) give

"

" high-density " polyethylene (Ziegler). My interpretation is that P.T.F.E. in a finely divided state, prepared by scraping a solid piece of this material, left the particles with loosely attached molecules of some fluorinecontaining substance which was eluted into the tissues to produce the systemic reaction, and thereafter the particles produced a mild local irritation and eventually became sealed off by fibrous tissue. It is proposed to remove the nodules for histological examination during the course of the next year or two.

There is obviously more in this subject than can be dealt with in a letter, but my immediate object is: (1) a

SiR,ňIwrite to corroborate the preliminary results and impression formed by Mr. Sharman (Dec. 7) about the new immunological pregnancy test which has been developed by the Ortho Research Foundation (I understand

to

"

be termed the

Grav Index Test

").

Previously this

department has conducted trials, with clinical follow-up, using several other pregnancy tests based on the same principle and with similar results to the many published reports. Having recently completed our first 200 tests using the new Ortho slide technique I confirm that there have been no false positives; there have been two false negatives, one in which the source of the urine remained in doubt, and the second from a case which was delivered at full term a fortnight later. The method, as Mr. Sharman expresses it, is undoubtedly a major breakthrough in pregnancy testing " and has already proved extremely useful for outpatient clinics in dealing with the potential young mother and the obese difficult-to-examine lady, and also in suspected abortion. We have found the test remains positive until the second day after full-term delivery, with a diminishing proportion of positives until the sixth day when all are negative. The results are similar in cases of abortion until complete placental failure. "

Provided the reagents can be produced in large quantity and with sensitivity carefully standardised for each batch, I see no reason why this elegant test should not for most purposes replace the Hogben test; but I think its place should remain in the clinical laboratory. Department of Pathology, Dryburn Hospital, Durham.

J. E. ENNIS.

SALARIES OF MAKERS OF SURGICAL APPLIANCES

SIR,-Iread with great interest Mr. Harrison’s letter of Nov. 9. These craftsmen are indeed very badly paid and it is unfortunate that it has needed the thalidomide children to bring to notice the skill it requires to help disabled people. Of course this state has not come about solely because of the thalidomide children-gross deformities in smaller numbers have always had to be dealt with by the skill of the surgical appliance maker. The fact that powered limbs are used is incidental, for it is often only the application of power to appliances which have already been used in the past. I should also like

to

point

out

the

plight

of the

surgical

bootmakers, which has also reached as sad a state-if not worse. When a surgical bootmaker is trained, the rate of pay laid down by the Whitley Council is only gel 2 10s. 8d. Many firms do pay over the rate, to obtain skilled craftsmen, but for many departments the rate for both appliance makers and surgical bootmakers has to be strictly adhered to. My point in writing is to emphasise the great danger that the manpower of a key service will decline beyond recovery. For it is true, and has been for the past few years, that very few people are coming into either industry. Drastic action must be taken immediately, before all the skill, knowledge, and proficiency built up over the years is lost during the present

generation. I am the chairman of the education committee of the Institute of British Surgical Technicians and I am finding it more difficult as time goes on to obtain students who are