Comparison of contamination of femoral heads and pre-processed bone chips during hip revision arthroplasty.

Total joint arthroplasties (TJA) are considered as high-risk operations,
especially revision procedures. A potentially devastating complication of total
hip surgery is infection. Infections result in a reduced quality of life and
greater physical limitations. Furthermore, the costs of hospitalisation of an
infected patient are about 3.7 times higher than the costs of hospitalisation
of an uninfected patient (Whitehouse, Friedman et al. 2002). The risk of
infection associated with hip revision surgery is significantly higher than the
risk associated with primary hip surgery. (Ridgeway, Wilson et al. 2005)
(Wilson, Charlett et al. 2008).
Procedures in which biomaterials are involved have a high risk for future
infectious problems, because infecting organisms adhere and grow to form a
biofilm on the biomaterial surface. This biofilm protects the infecting
organisms against natural host defences and antibiotic therapy and otherwise
relatively low-virulent organisms become common infecting organisms (Gristina
and Costerton 1985).
Transfer of bacteria from the skin of the patient or theatre personnel through
instruments and other materials to the wound area, results in intraoperative
contamination (Davis, Curry et al. 1999).
The use of pre-processed, ultra clean bone chips during impaction grafting in
hip revision surgery might result in a reduction of bacterial contamination.
For defect reconstruction in hip revision surgery, allograft cancellous bone is
used. This allogeneic bone can be fresh frozen total femoral head or
pre-processed bone chips. The preparation of bone chips for impaction grafting
at the operating theatre is a procedure which involves more instruments and
personnel compared to the use of pre-processed bone chips. Mostly, the
preparation of these bone chips in the operating theatre takes place outside
the plenum and takes for about ten minutes. Pre-processed bone chips are
prepared at a clean room at the bone bank. During this preparation, cultures
are taken of the bone chips and allografts with a positive culture are
discarded. As a result of the possible reduction in contamination, infection
rates might also decrease. Furthermore, time for preparation of the bone chips
is reduced, since morselising the femoral head and rinsing the bone chips is
not necessary, sparing expensive operation theatre time. Costs of these
pre-processed bone chips are higher compared to the costs of a femoral head.
Therefore, the advantages of the pre-processed bone chips have to be shown.

Do pre-processed bone chips have lower contamination rates compared to femoral
heads, morselised at the operating theatre measured at different moments during
hip revision arthroplasty?

The study is a prospective randomised trial comparing the outcomes between
bacterial contamination of pre-processed bone chips and femoral heads
morselised at the operating room.

Two groups will receive either pre-processed bone chips or a femoral head,
morselized at the operating room. Contamination rates will be measured by
swabbing the bone surface.

The normal ad standard potential risks and benefits are clinical relevant in
the trial.
The potential risks for revision hip surgery in general are:
- infection
- post-operative pain


The potential benefits for the use of pre-processed bone chips during the
operation are:
- reduced chance of infection
- reduction of operation time