Joint replacement surgery or Arthroplasty to give it its medical name is a very successful operation commonly performed at just about all medical institutions across the world. This operation performed by skilled orthopaedic surgeons restores joint function and eradicates pain usually caused by arthritic joints. The most commonly replaced joints are the large weight-bearing hips and knees but a variety of other smaller joints can also be replaced (including, ankle, shoulder, elbow etc).

For the most part these operations are very successful and patients progress with little or no complications. It is generally agreed by most experts in the field, that infection of an artificial joint is probably the most devastating complication, often requiring long courses of antibiotics and usually another operation to replace the infected joint. It is worth noting that once a prosthetic joint is infected it is not usually  possible to eradicate the infection without removing the infected material, no matter how many antibiotics are given or for how long!  This may include the metal implant and any associated bone cement (often used to fix the joint in position) or infected bone and tissue.

The main operations (called revisions) are the one-stage revision (one operation to remove the old infected prosthesis and at the same time put in a new prosthesis alongside appropriate antibiotics which could be for several weeks) or the two-stage revision (two operations – first operation to remove the infected prosthesis, administer antibiotics for a set period of time and then a second operation to insert a new prosthesis).

Essentially all the implanted material is removed and antibiotics are given (either intravenously or orally or sometimes using antibiotic loaded bone cement). The 2 stage revision has a slightly higher success rate than the single stage revision but requires 2 operations as opposed to one.

The choice of operation performed will depend largely on the preferred method of the revision surgeon. Whichever approach the surgeon takes the key element is to get a correct microbiology diagnosis (i.e. to detect and correctly identify the responsible bacteria). Once diagnosed, the surgeon is informed of which antibiotic(s) will be most effective to treat the infection and how best those antibiotics can be delivered, intravenously, orally or loaded in to bone cement.

Samples not being taken, insufficient samples or bad laboratory techniques may lead to the infection not being detected.  Conversely the techniques used in the laboratory are so sensitive that the slightest contamination of the sample(s) in surgery or at the sample processing stage may lead to incorrect results.  The organisms responsible for most orthopaedic infections can be present on the skin of the patient, the surgery team and laboratory staff.  In surgery, the use of antiseptic skin preparation and the clean environment of the operating theatres reduce the contamination risk. Here at the UK Orthopaedic Microbiology Service we have a dedicated senior laboratory scientist with 21 years experience in the laboratory diagnosis of such infections ensuring that the tissue samples are handled by trained staff under laminar flow conditions (the same conditions as used by the surgeon doing the operation in the theatre) to minimise the risk of laboratory contamination and ensure patients are treated with the right antibiotics for the right bacteria.

UKOMS also boasts a dedicated medically qualified microbiology consultant who is a nationally respected Orthopaedic Microbiologist to help interpret the results, help the surgeon to plan the options for revision surgery and inform them of the best choice of antibiotics, all of which is required to achieve a successful outcome.

If you would like further information  please contact the management team at UKOMS.