Dear Sam,

I believe the refs  below go some way to providing the answer. Is this
useful? Have you got access to the Koebner refs.?

1.      Post-operative infections

        Authors
             Drancourt M. Argenson JN. Tissot Dupont H. Aubaniac JM. Raoult
D.
        Institution
             Laboratoire de Microbiologie, Hopital de la Timone, Marseille,
France.
        Title
             Psoriasis is a risk factor for hip-prosthesis infection.
        Source
             European Journal of Epidemiology. 13(2):205-7, 1997 Feb.
        Abstract
             Risk factors for hip and knee prosthesis infection have been
described, but not psoriasis. Eighty five infected patients from different
centers and 202 non
             infected patients were included in a case-control study.
Fifteen of 85 infected patients (17.6%), and 2 of 202 (1%) non infected
patients had psoriasis.
             Odds ratio for infection in patients with psoriasis is 21.4
(4.7-195.5), and 39.7 (5.3-1718.8) in patients with hip prosthesis and
psoriasis. No significant
             difference was found in patients with knee prosthesis. These
data indicate that psoriasis is a risk factor for hip prostheses infection.


2.      Koebner Syndrome and psoriasis

Authors
     Mohla G. Brodell RT.
Institution
     University Hospitals of Cleveland, USA.
Title
     Koebner phenomenon in psoriasis. A common response to skin trauma.
Source
     Postgraduate Medicine. 106(3):39-40, 1999 Sep.

Authors
     Boyd AS. Neldner KH.
Institution
     Department of Dermatology, Texas Tech University Health Sciences
Center,  Lubbock 79430.
Title
     The isomorphic response of Koebner [see comments]. [Review] [83 refs]
Source
     International Journal of Dermatology. 29(6):401-10, 1990 Jul-Aug.

Authors
     Rosenberg EW. Noah PW.
Institution
     Department of Medicine (Dermatology), University of Tennessee College
of Medicine. Memphis.
Title
     The Koebner phenomenon and the microbial basis of psoriasis. [Review]
[37 refs]
Source
     Journal of the American Academy of Dermatology. 18(1 Pt 1):151-8, 1988
Jan.


Best wishes,

Reinhard

                -----Original Message-----
                From:   BROWN Sam, Library Services Manager
[mailto:[log in to unmask]]
                Sent:   30 March 2001 13:17
                To:     [log in to unmask]
                Subject:        clinical episode enquiry

                We have been pretty stumped by the following enquiry, have
looked in all the
                obvious places and was wondering if anyone may have any good
ideas? Its come
                to the library via the patient info centre which explains
its nature.

                What % of patients with psoratic arthritis who have had knee
replacements
                suffer from post operative infection?
                also how many of these eventually suffer from the Koebner
phenomenon.

                The Koebner phenomenon is a very common problem for people
with psoratic
                arthritis which can occur after ANY skin damage such as a
wound, operation
                or even a bad scratch.