HHE Rheumatology 2019 | Page 16

procedure was associated with the best outcome and highlighted that not using antimicrobial impregnated cement was associated with risk of re-infection. 7 For all the reasons mentioned, the risk of re-infection of the prosthetic joint is unsurprisingly higher in patients with RA-up to 25% compared with 5% in the general population in both of these studies even with a two-stage procedure. Both studies showed contrasting results with regards to immunosuppressive therapies and the influence on outcomes, leaving this an area for future research. Ultimately any non-randomised control study looking at surgical outcomes in this field is limited by the fact that patients undergoing a two-stage procedure are more likely to have favourable joint anatomy and have fewer comorbidities. This reflects the fact that the final operative management rests with the surgical team. With regards to medical or antimicrobial therapy of PJI infections this is highly individualised by the micro-organisms and their susceptibilities. Every patient with PJI should be reviewed by an infection specialist. The IDSA 10 recommends two to six weeks of pathogen specific therapy in combination with oral rifampicin in susceptible isolates with follow-on oral therapy for three months in total hip replacement and six months in total knee replacement. It also states that IV therapy should go on for four to six weeks if rifampicin cannot be used, but evidence is lacking and this is not our local practice. Lifelong suppressive antimicrobials may be considered if removal or further revisions cannot be performed. With regards to a patient with RA and PJI, the specific medical management might also be affected by drug interactions with immunosuppressive therapy and decisions must be made within a skilled specialist multidisciplinary team. Other important medical management considerations in PJI infection in RA is the discontinuation of immunosuppressive therapy in elective patients admitted for revision arthroplasty. This should be performed in conjunction with a rheumatologist, especially when considering stopping long-term corticosteroids due to the risk of developing acute adrenal insufficiency. The international consensus meeting on peri-prosthetic joint infections defined timings based on half-lives for stopping immunomodulatory therapy for elective joint replacement. This remains an area for research in patients with PJI. The decision to stop, reduce or continue with the current immunosuppression will require an individualised risk vs benefit analysis. As with diagnosis, follow up and response to medical and surgical of PJI in RA can be challenging. The joint might be inflamed and biomarkers may be persistently raised due to the patients underlying inflammatory condition rather than persistent infection. Conclusions PJI infection in RA remains more common than in the general population and is challenging to diagnose and manage. Treatment should be individualised under a multidisciplinary team in a specialised centre. Areas of future research to provide a better evidence base include the effect of RA and immunomodulatory therapies on the newer specific bacterial biomarkers and the effect of immunosuppressive therapies on recovery from PJI infection. 16 HHE 2019 | hospitalhealthcare.com References 1 Kapetnovic MC et al. Orthopaedic surgery in patients with rheumatoid arthritis over 20 years: prevalence and predictive factors of large joint replacement. Ann Rheumatol Dis 2008:67;1412–16. 2 Berbari EF et al. Risk factors for prosthetic joint infection: case-control study. Clin Infect Dis 1998;27:1247–54. 3 Parvizi J at al. Definition of periprosthetic joint infection. J Arthoplasty 2014;29(7):1331. 4 Bottner F et al. Interleukin-6, procalcitonin and TNF-alpha: markers of peri-prosthetic infection following total joint replacement. J Bone Joint Surg 2007;89:94–9. 5 Sousa R et al. Improving the accuracy of synovial fluid analysis in the diagnosis of prosthetic joint infection with simple and inexpensive biomarkers: C-reactive protein and adenosine deaminase. Bone Joint J 2017;77:351–77. 6 Berbari EF et al. Outcome of prosthetic joint infection in patients with rheumatoid arthritis: the impact of medical and surgical therapy in 200 episodes. Clin Infect Dis 2006;42:216–23. 7 Hsieh PH, Huang KC, Shih HN. Prosthetic joint infection in patients with rheumatoid arthritis: an outcome analysis compared with controls. PLoS One 2013;8:e71666. 8 Tsaras G et al. Utility of intraoperative frozen section histopathology in the diagnosis of periprosthetic joint infection: a systematic review and meta- analysis. J Bone Joint Surg Am 2012;94:1700–11. 9 Trampez A et al. Sonication of removed hip and knee prostheses for diagnosis of infection. N Engl J Med 2007;357:654–63. 10 Osmon DR et al. Executive summary: diagnosis and management of prosthetic joint infection: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis 2013;56:1–10.