Infection Prevention

As a surgeon, the one thing that I would like to avoid in all cases is a deep-seated infection in the face of a joint replacement.  The problem with deep-seated infections is that the bacteria are quite clever and produce a type of coating around the implant which we call biofilm and this prevents access of antibiotics to the bacteria. Therefore, the only way to remove these bacteria is to get at the infection early and mechanically clean the implants which unfortunately in many cases means removal of the original implants. A temporary implant is then placed in the joint which is often coated with an antibiotic loaded bone cement.  This is often left in place for up to 6 or 8 weeks following which the new definitive implant is then reinserted.  During this time numerous tissue specimens are taken and incubated in the laboratories in order to determine the sensitivity profile for the various possible antibiotics that we can use.  Obviously this will be very traumatic for anyone having to undergo numerous operations, being on numerous medications and having the repeated blood tests.  Not to mention the pain associated with having to go through all of this.  In some cases we are able to do a primary revision and remove the infected implant and replace it directly with a new implant, however, this is determined by a very specific set of circumstances.

The best cure for infection is prevention.  Prevention is a multifaceted approach.  Firstly, the host or otherwise known as the patient, needs to have an optimised immune system, so for example if you are diabetic you need to have good diabetic control.  If you have HIV, you need to be on antiretrovirals and blood tests need to demonstrate no viral load and a very high CD4 count.  Rheumatoid patients may need to come off their biologics in order to optimise the immune system for a period of time.  These are just a few examples.  Included in this is nutrition, so Vegan’s need to take protein supplement as protein is the building block for the healing processes in and around surgery and also forms the building blocks for a number of the antibodies produced in our systems.  I do not operate on any patient who would have a septic wound at the time of a joint replacement booking.  This needs to be managed and cured beforehand.  Patients with severe dental hygiene problems and halitosis need appointments to dentists in order to sort out their dentition prior to a joint replacement operation.  In my practice we will screen patients for carrier status with respect to multi-resistant bacteria as these can be managed with topical lotions and shampoos prior to the operation.

An interesting, yet little known fact is that the percentage weight of the DNA that makes up each of us, which in fact belongs to the bacteria that live on us and in us can equate to as much as 70%.  That’s right, only 30% of the DNA by weight that makes up you in fact belongs to you.  The rest belongs to the organisms that live symbiotically with you.  These are the organisms which result in infection.

There is currently a school of thought that every hip or knee replacement is inevitably colonised by some of these bacteria and that the development of an infection is principally related to the total load of this colonisation put together with the immune status of the host and/or patient.  So with respect to the former, it is important to wash the night before with a special chlorhexidine-based soap and shampoo, to climb into a clean linen bed and only arrive in hospital on the day of the operation.  In my practice your skin will be prepared with a Betadine or iodine-based antiseptic and the surgical site covered with a sterile towel prior to going to surgery.  Once you have been placed on the operative table, I then isolate your groin and clean your skin again, but now with a Betadine and alcohol preparation.  We then spend time preparing the instruments and draping you with sterile drapes following which we again clean the skin, now with chlorhexidine and alcohol.  Only the area that I will use to make the incision is exposed, and even this small area of skin is covered with an iodine impregnated plastic film.  This film is not removed until the last suture is put in.  The concept here is to isolate the bacteria on your skin from the wound during the entire course of the procedure.  We work in Laminar flow theatres and the personnel passage through the theatre is strictly limited. I am blessed to be able to work with a fixed team of professionals who know my protocols exactly, therefore the speed of the operation is optimised.  All of these factors work towards minimising the risk of infection.

As you go to sleep there is a dose of antibiotics given intravenously so that by the time I cut into the skin the blood is saturated with antibiotics.  The antibiotic prophylaxis is continued intravenously for a period of 24 hours after the operation.  Further aspects that contribute to limiting infection are the following: cleaning the skin again with chlorhexidine and alcohol  prior to putting the dressings on.  I use skin glue as well as suture strips and these are then followed by an occlusive plastic film dressing which seals the wound from the outside environment.  If there is no bleeding which is most often the case, this dressing does not require removal and will remain on for a period two weeks in total.  It has been shown that less fiddling with the dressings results in less wound infection.  This dressing is waterproof enough to shower with.  Obviously as surgeons we are covered from head to toe with sterile gowns and head coverings including masks so that as much of our skin is isolated preventing any contamination of your wound.

During surgery we work at a measured pace with a very specific workflow in order to minimise open wound time. Prior to closure of the wound with the absorbable sutures, the implant and the wound is washed with a pulsatile lavage device resulting in 3 litres of sterile fluid being used every time; the idea being that we will remove any possible bacteria that may have contaminated the wound and thereby minimise bacterial load and risk for infection.  The closure of the wound is again meticulous and in the multiple layers so as to form a watertight seal, again this should prevent bacteria getting into the wound from the skin edges.

As you can see, from this note, everything humanly possible is done based on current evidence and consensus opinion in order to minimise the chance of infection.  Despite all of this however, infection does occur and will be aggressively managed.