Ruling out underlying infection in 200 presumed aseptic knee and hip revision arthroplasties using a multiplex PCR system.

Ruling out an infection in one-stage knee and hip revisions for presumed aseptic failure by conventional tissue cultures takes up to 14 days. Multiplex polymerase chain reaction (mPCR) is a quick test (4-5 h) for detecting pathogens. The purpose of this study was to evaluate the diagnostic accuracy of an automated mPCR of synovial fluid obtained intraoperatively in unsuspected knee and hip revisions. A prospective study was conducted with 200 patients undergoing a one-stage knee or hip revision. Synovial fluid was analyzed with the mPCR Unyvero implant and tissue infection G2 cartridge (U-ITI G2) system and compared to intraoperative tissue cultures. The primary outcome measure was the diagnostic accuracy, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), of the mPCR U-ITI G2 system compared to conventional cultures. In the knee revision group, there were no patients with a positive mPCR in combination with positive cultures. This resulted in a non-calculable sensitivity and PPV. The specificity and NPV in the knee revision group of the mPCR compared to tissue cultures was 96.8% and 96.8%, respectively. In the hip revision group, the sensitivity, specificity, PPV, and NPV of the mPCR compared to tissue cultures was 36.4%, 96.6%, 57.1%, and 92.5%, respectively. Sixteen mismatches occurred between the mPCR and tissue cultures. The mPCR U-ITI G2 system is a quick and reliable synovium fluid test for ruling out infection in presumed aseptic knee and hip revisions with a high NPV compared with tissue cultures, although some mismatches were observed. Periprosthetic tissue cultures are still advised as back-up for false negative and positive mPCR test results.

Reinfection and re-revision rates of 113 two-stage revisions in infected TKA.

Introduction: Two-stage revision is the most frequently performed revision procedure of a (suspected) periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). The reported results of this treatment show large variability between studies, ranging between 0 - 40 percent failure. The purposes of this study were to determine long term (1) reinfection rate, (2) re-revision rates for any reason, and (3) the reinfection rate of patients with positive cultures at reimplantation. Methods: We prospectively followed and retrospectively reviewed 113 consecutive two-stage revision TKAs, performed between 2003 and 2013 in our clinic with a minimum follow-up of 2 years. Diagnosis of PJI was based on the major Musculoskeletal Infection Society criteria for PJI. Results: After a mean follow-up of 94 months (range 24-172 months), infection recurred in 23 cases (23%). Of these, nine cases (9%) were defined as relapse (same micro-organism as index revision) and in 14 cases another causative was found (14%). In 11 patients debridement, antibiotics and retention of the prosthesis successfully eradicated the reinfection. After overall follow-up 17 patients (17%) underwent re-revision surgery, 11 patients (11%) due to an infection and 6 patients (6%) for aseptic reasons. Conclusions: Treatment of a (suspected) infection of a TKA by a two-stage revision had acceptable results based on re-revision and re-infection rates in the long term (>5 years), resembling the short-term results (<2 years). Focussing on the cultures at the index two-stage revision, episodes of relapse and new infections during follow-up were almost equally divided. Reinfection rates were higher in cases with positive cultures at reimplantation. Patients should be counselled appropriately in this particular situation.

Evaluation One Year after DAIR Treatment in 91 Suspected Early Prosthetic Joint Infections in Primary Knee and Hip Arthroplasty.

INTRODUCTION: Early recognition and appropriate initial treatment with debridement, antibiotics and implant retention (DAIR) if a suspicion of an early prosthetic joint infection (PJI) is present can eradicate infection on first attempt and prevent implant failure. We evaluated the outcome after 1 year of patients treated with DAIR after primary total knee arthroplasty (TKA) or total hip arthroplasty (THA). Furthermore, we determined preoperative, microbiology, and treatment factors related to failure after DAIR. METHODS: A retrospective cohort study was assembled with 91 patients undergoing DAIR with a high suspicion of an early PJI. Records were reviewed for demographics, preoperative laboratory results, microbiological data, given treatment and postoperative follow-up. The primary outcome was infection-free implant survival at 1 year. Repeated DAIR was not considered as treatment failure. RESULTS: The rate of infection-free implant survival following DAIR in a suspected early PJI was 85% (95% confidence intervals (CI) 78-91). Cultures remained negative in 20 patients, with no occurrence of infection during follow-up. A higher failure rate was seen in early PJI caused by Enterococcus faecalis (p=0.04). Multivariate analysis showed a statistically significant association between treatment failure and high C-reactive protein level (CRP >100) (odds ratio 10.0, 95% CI [1.5-70]) and multiple DAIR procedures (≥2) (odds ratio 5.0, 95%CI [1.1-23]). CONCLUSION: If an early PJI is suspected DAIR is the appointed treatment with up to 2 debridement procedures. Since culture-negative DAIRs were not related to any complications during follow-up, overtreatment of suspected PJI seems to do no significant harm with respect to implant failure.

Risk Factors and Clinical Outcomes of Head and Neck Cancer in Inflammatory Bowel Disease: A Nationwide Cohort Study.

Background: Immunosuppressed inflammatory bowel disease (IBD) patients are at increased risk to develop extra-intestinal malignancies. Immunosuppressed transplant patients show increased incidence of head and neck cancer with impaired survival. This study aims to identify risk factors for oral cavity (OCC) and pharyngeal carcinoma (PC) development in IBD, to compare clinical characteristics in IBD with the general population, and to assess the influence of immunosuppressive medication on survival. Methods: We retrospectively searched the Dutch Pathology Database to identify all IBD patients with OCC and PC between 1993 and 2011. Two case-control studies were performed: We compared cases with the general IBD population to identify risk factors, and we compared cases with non-IBD cancer patients for outcome analyses. Results: We included 66 IBD patients and 2141 controls with OCC, 31 IBD patients and 1552 controls with PC, and 1800 IBD controls. Age at IBD diagnosis was a risk factor for OCC development, Crohn's disease (CD; odds ratio [OR], 1.04; 95% confidence interval [CI], 1.02-1.07), and ulcerative colitis (UC; OR, 1.03; 95% CI, 1.01-1.06). For PC, this applied to UC (OR, 1.05; 95% CI, 1.01-1.06). IBD OCC cases showed impaired survival (P = 0.018); in PC, survival was similar. There was no effect of immunosuppression on survival. Human papillomavirus (HPV) testing of IBD cases revealed 52.2% (12/23) HPV-positive oropharyngeal carcinomas (OPCs). Conclusion: This study shows that IBD is associated with impaired OCC survival. Higher age at IBD diagnosis is a risk factor for OCC development. We found no influence of immunosuppression on survival; 52.2% of OPC in IBD contained HPV.

Treatment of prosthetic joint infections due to Propionibacterium. Similar results in 60 patients treated with and without rifampicin.

BACKGROUND AND PURPOSE: Currently, Propionibacterium is frequently recognized as a causative microorganism of prosthetic joint infection (PJI). We assessed treatment success at 1- and 2-year follow-up after treatment of Propionibacterium-associated PJI of the shoulder, hip, and knee. Furthermore, we attempted to determine whether postoperative treatment with rifampicin is favorable. PATIENTS AND METHODS: We conducted a retrospective cohort study in which we included patients with a primary or revision joint arthroplasty of the shoulder, hip, or knee who were diagnosed with a Propionibacterium-associated PJI between November 2008 and February 2013 and who had been followed up for at least 1 year. RESULTS: We identified 60 patients with a Propionibacterium-associated PJI with a median duration of 21 (0.1-49) months until the occurrence of treatment failure. 39 patients received rifampicin combination therapy, with a success rate of 93% (95% CI: 83-97) after 1 year and 86% (CI: 71-93) after 2 years. The success rate was similar in patients who were treated with rifampicin and those who were not. INTERPRETATION: Propionibacterium-associated PJI treated with surgery in combination with long-term antibiotic administration had a successful outcome at 1- and 2-year follow-up irrespective of whether the patient was treated with rifampicin. Prospective studies are needed to determine whether the use of rifampicin is beneficial in the treatment of Propionibacterium-associated PJI.