Prof Dr Ojan Assadian L&R Prevent and Protect

Best practice

Avoiding infections with hip and knee prostheses: The success of the operation also depends on patients’ cooperation

Prof. Dr. Ojan Assadian, President of the Austrian Society for Hospital Hygiene (ÖGKH) and Medical Director at the State Hospital Neunkirchen, was co-author of an expert opinion paper of the "Initiative Sicherheit im OP" (SIOP) on infection prevention in hip and knee endoprosthetics. In an interview, he provides insights into the most important points of the paper. In his opinion, however, the most promising preventive measure is not in his hands at all: Leading a healthy lifestyle could contribute a great deal to avoiding the need for surgery in the first place and hence the risk of infection.

In your opinion, why did it make sense to prepare an expert opinion paper on infection prophylaxis specifically for hip and knee endoprosthetics?

Prof. Dr. Ojan Assadian: Today, implantations of hip and knee prostheses are considered the "surgery of the century." For about ten years now, the proportion of SSIs has been around 0.5 – 1 infection per hundred patients. Well-planned interventions generally have a lower risk of infection than emergency operations. But even an infection risk of less than 1 percent is still not good enough for us. This is because deep infections, in particular, mean serious complications for those affected, who have to be treated for weeks or even months. In some cases, deep infections can lead to the loss of a limb or even death. It was important for us to take an interdisciplinary look at the feasible options for infection prophylaxis with this expert opinion paper. In the paper, the different aspects from the areas of hospital hygiene, infectology, orthopaedics, nursing and anaesthesia were considered and taken into account.

Do the references in this expert opinion paper actually differ from those of the Robert Koch Institute?

Assadian: In my view, there are no fundamental technical differences. We have only closed some gaps, such as from the point of view of anaesthesia. As one example, we would like to point out that especially in the context of endoprosthetic care, great attention must be given to ensure that central venous catheters are available. All in all, the catheter issue was worthy of greater consideration for us in order to also point out that infection protection in the field of orthopaedics is not limited to endoprostheses.

Has the Corona pandemic changed any aspects of your recommendations?

Assadian: No. However, during the peak phase of the Corona pandemic in Austria in April and May, we saw a maximum backlog of planned operations. Many orthopaedic patients in particular suffer from additional illnesses that may make intensive medical care necessary in the first two to three days after the operation. In order to avoid bottlenecks in ventilation, it is known that these places have been reserved for patients with COVID-19. The challenge will now be to safely care for the waiting patients, who all have a medical indication for a surgical intervention. Of course, this issue does not change the basic risk of wound infections.

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In your experience, which group of patients has the greatest risk of developing SSIs?

Assadian: This group includes the patients who, due to obesity and a lack of exercise and fitness, also often have extremely strained joints and need a joint replacement. For example, we know that patients with a BMI over 40 have a high risk of infection. At the same time, patients with a very high body weight also have difficulty with remobilization after surgery.

What advice do you give patients in the run-up to an operation?

Assadian: First, of course, sufficient exercise and weight control are the best forms of prevention from infections or complications. In addition, there are special information events for patients and their relatives, which quite deliberately point out that patients should not carry out any activities that involve an increased risk of infection in the run-up to the operation. We have already pointed out – even before the corona pandemic – that patients should avoid attending large events in autumn or winter. But we also inform patients about the importance of their vaccine status and the advantages of a pneumococcal vaccination, especially for patients over the age of 65. It also seems to make sense to determine the patients’ dental status in the run-up to an operation and to eliminate possible cases of periodontitis as a source of SSI infections.

In your opinion, what significance do such preoperative measures have for the success of the operation?

Assadian: As a hygienist, this cooperation with the patients – especially in regard to infections – is essential and decisive for the success of the intervention. So we are also dependent on the patients being open about any fever or a burning sensation when they urinate on the day of the operation. An incipient urinary tract infection, for example, carries the risk of bacteria migrating from the bladder into the bloodstream, with the bacteria spreading and colonizing the freshly inserted prosthesis.

Which special measures are particularly important during a hip or knee operation compared to other surgical procedures?

Assadian: One of the focal points of any surgery with an implant is the air quality in the operating room. This is because when microorganisms from the environment colonise a foreign body, they can form a biofilm and thus become a long-lasting and difficult source of infection to clean. The top priority is, therefore, the pathogen-free installation of the endoprosthesis in the human body. Special ventilation systems can help here, but these alone do not guarantee particle-free air. These devices must be well planned, built and operated. For example, a retrofitted surgical lamp can also become a problematic source of dust particles.

What are your requirements for protective clothing?

Assadian: I would like to start by saying that the Corona pandemic has shown us how important medical devices and personal protective equipment are for the care of our patients. What is important is that the clothing protects the wearer from body fluids and blood contamination; in other words, that it forms a safe barrier. In addition, during orthopaedic operations, it is important that the sterile clothing does not release any, or as few, fibres as possible into the environment.

What should the surgical team take into account when treating wounds?

Assadian: Unfortunately, we are moving here in the under-explored intersection between nursing research and medical research. We have found that there are few well-conducted studies that investigate which wound dressings* best promote healing or are associated with the aspect of infection control. More scientific studies would be desirable here. In my view, it is important that suitable wound dressings protect against mechanical stress and contamination of the wound with microorganisms from the environment, and allow gas exchange.

How can patients themselves contribute to good wound healing?

Assadian: Again, getting exercise and healthy eating are important, but also there is also the topic of smoking. We know that smoking is a risk factor for good wound healing.

Do you have any tips on staff training?

Assadian: Especially recently we have gained a lot of experience with online training. Many aspects went better than we thought, and the interaction between the trainers and participants went very well. The professional competence of the web host was always essential. We will certainly intensify online training.

What were the moments of success in infection prophylaxis?

Assadian: An important measure, which has now become a standard throughout Central Europe, is certainly the subject of depilation. We would like to point out to our patients that they are not allowed to shave at the operation site the day before the operation. This is because the many small skin lesions that result are the entry point for many pathogens. However, clipping shortly before the operation with disposable material has proven to be a good method.

What challenges do you currently see in the area of SSIs in endoprosthetics?

Assadian: If a wound infection occurs, we must ensure good microbiological diagnostics. This is because infections are often highly complex and require good testing and specific therapeutic recommendations. Unfortunately, we have lost a lot of bacteriological and infectious expertise and centres in recent years.

*Commercial communication

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