EH 6_2015

Serum Urine systemic local Infection site EUROPEAN HOSPITAL  Vol 24 Issue 6/15 8 INFECTION CONTROL Topical antibiotic therapy is an indispensable add-on Reducing arthroplasty revisions: cutting costs and improving patient satisfaction Locally applied antibiotics are a component of effective infection management in orthopaedics and trauma surgery. Successful concepts are based on patient-specific surgical and antimicrobial treatment. At the symposium “Infections and high-risk patients: solutions for joint replacements and traumatology” at this year’s Congress on Orthopaedics and Trauma Surgery (DKOU) in Berlin last October, two experts discussed the best possible delivery of topical antibiotics. Use of antibiotic-loaded bone cement significantly lowers revision rates in hip and knee arthroplasty Any orthopaedic or trauma surgery intervention can cause an infection – a risk which is particularly high when a foreign object remains in the patient’s body, be it as a spacer or as the actual implant, as bacteria are prone to colonize the surface of objects. Thus, antibiotic therapy for infection prophylaxis is generally considered indispensible in ortho- paedics and trauma surgery, above all in high-risk patients such as multi-morbid or polytrauma patients. Risk management: a combination of topical and systemic antibiotics With these patients, however, the efficacy of systemic antibiotics is limited, explained Professor Wolfram Mittelmeier, speaker at the symposi- um and Director of the Orthopaedic Clinic at the University Hospital Rostock, Germany, since scars and low haemoperfusion of bones pre- vent the antibiotic from sufficiently reaching the targeted area. In ortho- paedics, he underlined, this is fre- quently a problem in multiple or subsequent surgeries with rather severe scarring. In traumatology, low topical con- centration of systemic antibiotics is usually due to peripheral hypo- tension and the severe bone and tissue damage caused by an acci- dent, said Professor Bühren, further Infection is a burdensome complica- tion of all types of surgery and espe- cially following arthroplasty. Implant removal and revision arthroplasty have a considerable impact on the patient and are associated with sub- stantially greater hospital and physi- cian resource utilisation, resulting in significantly higher costs compared to primary total joint arthroplasty. The use of antibiotic-loaded bone cements is a widely-practised meth- od of reducing orthopaedic infec- tions. The major appeal of incorpo- rating antibiotics in bone cements is the higher local concentrations of antibiotic achievable when it is delivered in this way, compared with intravenous administration. PALACOS® R+G (Heraeus Medical), which includes gentamicin, has been in use for over 40 years. At the Annual Meeting of the British Orthopaedic Association (Liverpool, September 2015), Heraeus Medical sponsored a satel- lite symposium to discuss “Infection in the high risk arthroplasty patient”. “We need to reduce arthroplasty revisions as a quality measure” com- mented Mr Mike Reed, Consultant Trauma and Orthopaedic Surgeon at Northumbria NHS Healthcare Foundation Trust, UK, who spoke at speaker and Medical Director of the Trauma Clinic Murnau, Germany. Thus the benefits of local delivery of antibiotics in orthopaedics and trauma surgery seem obvious: it ensure a sufficiently high concen- tration of the agent at the trauma site and reduces the side effects on the entire organism. Since to date there are few data supporting the long-term effect of topical antibiot- ics, the two experts agree, effec- the symposium. Mr Reed presented recent data from the National Joint Registry (NJR) of England, Wales and Northern Ireland (the largest arthro- plasty registry worldwide) support- ing the efficacy of antibiotic-loaded bone cements in the prevention of revision surgery. The data, span- ning 2004–2015, comprised 717,339 cemented total knee and 421,604 cemented total hip arthroplasty pro- tive infection prophylaxis requires a two-pronged approach: topical and systemic antibiotic therapy. The crucial issue with this approach, according to Professor Mittelmeier, is the proper selection of suitable antibiotics. While all commercially available antibiotics can be used for systemic therapy, only certain ones are suitable for topical delivery due to various features of the carrier sub- stances. Moreover, systemic antibiot- cedures. Of those, 47% and 59% of primary hip and knee arthroplasties respectively were performed using PALACOS® R+G. Results showed a statistically significant reduction in the number of both hip and knee arthroplasty revisions when using antibiotic-loaded bone cement, spe- cifically PALACOS® R+G, as com- pared to other bone cements. Mr Reed set up a randomized trial ics offer better and faster reaction to “hidden microbes” or to changes in the types of microbes present. Topical antibiotic delivery: cement is the gold standard In addition to the conventional deliv- ery of antibiotics, there are currently three methods to get topical antibi- otics to the desired site: antibiotic- impregnated PMMA beads (polyme- thyl methacrylate), collagen sponges and cement. While both experts considered antibiotic-loaded cement the substance of choice, they did point out that even this option is far from ideal: on the one hand a certain degree of “abrasion” of the cement is desired in order for the antibi- otic to be released into the body, on the other hand cement particles could settle in the surrounding joints and tissues increasing the infec- tion risk. Despite these drawbacks, Mittelmeier and Bühren agree: at this point in time the antibiotic-load- ed cement is the best option. Differences between prophylaxis and therapy Antibiotic-loaded cement is avail- able industrially manufactured; but the antibiotic may also be added to the cement manually which ensures a very high degree of spe- cific antibiotics release. With regard to prophylaxis in trauma surgery, Professor Bühren recommended the local concentration of the antibi- otic to be above the minimal inhibi- tory concentration (MIC) in order to avoid the development of resistance. However, a concentration which is of 848 patients undergoing hip hemi- arthroplasties; a good proxy for high risk arthroplasty patients due to the high infection rate observed in hip hemi-arthroplasty patients. Patients receiving high dose dual antibi- otic cement (COPAL® G+C, contain- ing gentamicin and clindamycin; Heraeus Medical) had significantly reduced surgical site infection rate compared to those receiving stand- ard antibiotic-loaded cement. Mr Reed dis- cussed how in his institution all lower limb joint replace- ments are carried out using antibiotic-load- ed cement, using high dose dual antibiotic cement for patients with a hip fracture requiring joint replace- ment. Commenting on whether cost may be an issue, Mr Reed noted “We’ve done a significant cost analy- sis and it shows that even though high dose dual antibiotic cement is more expen- sive, the cost to the hospital and the NHS too high can have adverse effects on the healing process. For orthopaedics Professor Mittel­ meier recommends again a two- pronged approach: low dose for prophylaxis purposes, high dose to combat detected microbes. For per- manent solutions - such as knee replacements - he strongly advised against manually adding antibiot- ics to the cement since any manual manipulation of the cement carries the risk of reducing the mechani- cal performance of the cement – a potential problem since the surgeon is liable in case the surgery fails. In addition to the dosage the retention time in the body plays a major role. Both experts recommend not leaving cement-loaded spacers in the body for too long. Ideally they should be removed after six to eight weeks in order to avoid bacte- rial colonisation and to ensure that not too many particles are released. Nevertheless, the decision to remove the spacer is closely linked to the results of microbe testing. Case by case decisions are required. By way of closing, both experts underlined that even the best anti- biotics combination does not neces- sarily avoid and treat an infection – the crucial element is noq. and will be, the quality of the surgical intervention, including meticulous debridement. is reduced, because of the infections prevented”. Analysis of long-term data is vital to prove differences in outcomes with orthopaedic devices and tech- niques. The NJR data are consist- ent with reports from other joint registries, including the Norwegian Arthroplasty Register and the Swedish National Hip Arthroplasty Register, which demonstrate that PALACOS® R+G displays the lowest risk of an implant failure among all bone cements analysed. To review the respec- tive valid reports of the NJR Implant Summaries, please visit the Heraeus Medical website www.herae.us/njr-data Mike Reed, Consultant Trauma and Orthopaedic Surgeon at Northumbria NHS Healthcare Foundation Trust Professprs Volker Bühren (left) and Wolfram Mittelmeier at the symposium Active compound concentration of systemic (left) and locally (right) administered antibiotics in the body

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