Infection control in orthopaedic surgery

One infection is one too many, ran the slogan behind Ethicon’s Surgical Site Infection Symposium at the ICC, Birmingham. There can be no doubting that hospitals across the country are committed to doing all they can to stop infection, yet lives continue to be blighted by surgical site infections, resulting in extended hospital stays for patients and huge costs for the NHS. Estimates put the cost of healthcare associated infections Europe-wide at Z6.3 million each year, with patients spending, on average, an extra 6.5 days in hospital. A 10% reduction in the infection rate could save Z150 m every year, more than 360,000 bed days and nearly 48,000 consultant sessions. The symposium brought together leading experts in the field of surgical site infection, and featured two presentations looking at orthopaedic surgery, where ‘taking responsibility for infection’ was the order of the day. Rhidian Morgan-Jones, a consultant at the University Hospital of Wales and Cardiff, said: “As surgeons we need to put our hands up and admit that we cannot blame the patient, we cannot blame the theatre, or theatre staff. Surgeons need to take responsibility for infection too and this should provide a good building block to improve our practices.” One of Mr Morgan-Jones’ specialisms is knee replacement and revision of failed knee replacements. “There are 70,000 knee replacements per year in the UK. Deep infection rates can vary from 0.5% to up to 2%. On average, this results in 700 cases of serious infection each year in knee replacements alone.” So, what measures can be taken to avoid infection? Mr Morgan-Jones suggests that one solution is not to operate. He explained his reasoning: “Every time you operate there is a risk of infection.” He offered the audience an example, using the case of a low energy break in the tibia, where a surgeon had made the decision to operate, inserting metalwork into the leg. The patient subsequently suffered from an infection. Mr Morgan-Jones suggested that, in this case, the bone would have healed without the need for surgical intervention if it had simply been left in plaster. In cases where surgery is unavoidable, Mr Morgan-Jones advised that tourniquets should be used for the shortest time possible suggesting that, for a knee replacement, a tourniquet should not be on for more than an hour, lessening the risk of infection. He also advised Trusts to consider moving to disposable single-use tourniquets. “Sometimes you do not have to use tourniquets on certain knee operations,” said Mr Morgan-Jones. “I use them because I like to have a bloodless field when I am working or cementing. However, they should not be used if the patient has a vascular disease.”

Surgical technique

Surgical techniques will also have an impact on infection. “We went through a phase of minimally-invasive surgery,” said Mr Morgan-Jones. “The wounds were worse, the positions of the implants were worse and we have now moved away from this type of surgery. Small incisions should be an outcome of good surgery; it should not be a primary goal.” Mr Morgan-Jones and his team at Cardiff have pioneered a tibial crest osteotomy with a suture technique that eliminates the need for screws or wires which can cause their own problems once you close the osteotomy. “This has revolutionised the practice of knee replacement in Cardiff,” he said. On sutures, Mr Morgan-Jones recommended that large knots should be minimised and absorbable sutures be used where possible. He also favours antibacterial sutures, such as Vicryl Plus. Staples may be necessary when skin quality is very poor and a suture is not going to hold. “Skin staples produce irritation and compression and can cause superficial infection, although there is no evidence of deep infection,” he said. Mr Morgan-Jones now uses the Aquacel absorbent dressing which absorbs and interacts with wound exudates to form a soft, hydrophilic, gas-permeable gel that traps bacteria and conforms to the contours of the wound. “Why Aquacel? It is absorbent. Wounds are going to leak and you want to absorb that leak.” Mr Morgan-Jones also has a fiveday rule on dressing changes for knee replacements. “No nurse is allowed to change the dressing within the first five days without prior discussion. Wounds heal if you leave them alone, but not if you take the dressing off to have a look at them. That, more than anything else will increase the risk of infection,” he said. “Five days is the length of time before patients are sent home following a knee replacement, so we change the dressing before the patient goes home.” There is a significant debate in orthopaedic surgery about thromboprophylaxis and the need for anti-thrombotic drugs. The National Institute for Health and Clinical Excellence (NICE) prescribes the use of oral Factor Xa inhibitors to reduce the rate of pulmonary embolisms (PE). “We have found that these drugs do work. They halved the PE rate, but made no difference to the incidence rate of deep vein thrombosis and doubled the haematoma rate and the return to theatre rate,” said Mr Morgan-Jones. “There is an advantage to these drugs and there is a big disadvantage. We need to be careful about following guidelines. As a community in Cardiff, we are starting to move back towards aspirin.”