Revision For Periprosthetic Joint Infection Research Articles

Does serum interleukin-6 guide the diagnosis of persistent infection in two-stage hip revision for periprosthetic joint infection?

PurposeThe diagnosis of persistent infection at reimplantation of two-stage revision arthroplasty for periprosthetic joint infection (PJI) remains challenging. Several studies have shown the benefit of serum interleukin-6 (IL-6) in diagnosing periprosthetic joint infection (PJI). Recent data indicated serum IL-6 could be promising in differentiating persistent infection. The purpose of this study was to validate the efficacy of serum IL-6 in diagnosing persistent infection at reimplantation.MethodsA retrospective review of 86 PJI patients with a two-stage exchanged hip arthroplasty from 2013 to 2017 was conducted. Persistent infection was defined using the modified Musculoskeletal Infection Society (MSIS) criteria combined with follow-up results. Serum IL-6 at reimplantation were collected and compared among patients with or without persistent infection. Receiver operating characteristic (ROC) curves were generated to evaluate the diagnostic performance and optimal cut-off value of serum IL-6 at reimplantation.ResultsSixteen cases were diagnosed as persistent infection at reimplantation. There was no significant difference in serum IL-6 levels between cases with persistent infection and controls (7.89 pg/ml vs. 5.56 pg/ml; P = 0.179). The area under the ROC curve (AUC) for serum IL-6 in diagnosing persistent infection at reimplantation was 0.59 (95% confidential interval [CI] 0.40–0.77). With the calculated threshold set at 8.12 pg/ml, the corresponding sensitivity, specificity, positive predictive value, and negative predictive values were 38%, 88%, 38%, and 87%, respectively.ConclusionSerum IL-6 is inadequate in diagnosing persistent infection at reimplantation for two-stage revision arthroplasty. With the serum IL-6 threshold set at 8.12 pg/ml, the specificity to rule out persistent infection is high, but the sensitivity to predict persistent infection is not satisfactory.

Propidium monoazide–polymerase chain reaction for detection of residual periprosthetic joint infection in two-stage revision

False negative culture results in periprosthetic joint infection (PJI) are not uncommon particularly when patients have received long term antibiotics. Polymerase chain reaction (PCR) has a lower specificity partly due to detection of residual DNA from dead bacteria. Propidium monoazide (PMA) prevents DNA from dead bacteria from being amplified during the PCR. This study aimed to determine the role of PMA in PCR for diagnosis of PJI. Clinical samples were tested by PCR with and without prior treatment with PMA and compared to conventional microbiological culture. The PCR assay included genus-specific primers for staphylococci and enterococci and species-specific primers for Cutibacterium acnes. The validated conditions of PMA treatment used in this study were 20 μM concentration and 5 and 10 min of dark incubation and photo-activation respectively. 202 periprosthetic tissues and explanted prostheses from 60 episodes in 58 patients undergoing revision arthroplasties for either PJI or non-infective causes were tested, by culture, PCR, and PMA-PCR. 14 of the 60 episodes satisfied the Musculoskeletal Infection Society (MSIS) criteria for PJI and 46 did not. Sensitivity of culture, PCR, and PMA-PCR were 50%, 71%, and 79% respectively. Specificities were 98%, 72%, and 89% respectively. All figures were calculated for episodes rather than samples. PMA-PCR enhanced both the specificity and the sensitivity of PCR. It has the potential to detect residual bacterial viability prior to reimplantation in the two-stage revision for PJI.

CORR Insights®: What are the Factors Associated With Re-revision After One-stage Revision for Periprosthetic Joint Infection of the Hip? A Case-control Study.

CORR Insights®: What are the Factors Associated With Re-revision After One-stage Revision for Periprosthetic Joint Infection of the Hip? A Case-control Study.

Hip Spacers in Two-Stage Revision for Periprosthetic Joint Infection: A Review of Literature.

Infection after total hip arthroplasty (THA) is a devastating complication with significant consequences for patients. In literature, single and two-stage revision, irrigation and debridement, Girdlestone resection arthroplasty, and arthrodesis and amputation are reported as possible treatments. Recently, two-stage revision has become popular as the gold standard treatment for chronic hip joint infections after THA. In this review, we evaluate the current literature about microbiology of periprosthetic joint infections and the use of antibiotic-loaded cement spacers. We aim to give an overview about indications, clinical results, and mechanical complications for spacers implantation, evaluating also selection criteria, pharmacokinetic properties, and systemic safety of the most frequently used antibiotics.

What are the Factors Associated with Re-revision After One-stage Revision for Periprosthetic Joint Infection of the Hip? A Case-control Study.

Despite increased interest in one-stage revision arthroplasty for periprosthetic joint infection (PJI) of the hip, the reported infection-free proportions after the one-stage approach are still comparable to that of two-stage revision. However, we still lack studies that analyze factors associated with any re-revision after one-stage revision arthroplasty for PJI. After one-stage revision arthroplasty for PJI of the hip, what factors were associated with an increased risk of re-revision, and what factors were associated with an increased risk of reinfection? We performed a single-center retrospective case-control analysis. Patients who underwent one-stage revision arthroplasty for PJI of the hip in our hospital between 2009 and 2017, and who were subsequently re-revised due to any reason, including reinfection, were identified from our electronic medical records. A total of 121 patients who underwent repeat revision for any reason after one-stage exchange for PJI of the hip were identified. The re-revision procedures were performed after a mean of 407 days. The primary reasons for re-revision were repeated hip dislocation in 53 of 121 patients (44%), reinfection including both new and persistent infections in 40 of 121 patients (33%), and aseptic loosening in 16 patients (13%). Forty-three patients underwent another revision procedure after the re-revision procedure (43 of 121; 36%). More than 40 potential patient-, joint- and surgery-related risk factors were investigated and compared with a 1:1 matched control participants by age, sex and year of the one-stage revision. Similar to the re-revision patients, controls were treated for PJI with one-stage revision arthroplasty; however, they did not undergo subsequent revision for any reason by the latest followup examination. The mean followup of the control group was 66 months (range, 17-119 months). The mean length of hospital stay was 26 days in the re-revised group (SD, 11.6 days) compared with 22 days for the controls (SD, 6.6 days). All analyses were performed to identify factors associated with general re-revision and reinfection. The independent factors associated with repeat revision for any reason were persistent wound drainage for at least 1 week (odds ratio [OR], 7.4; 95% CI, 2.6-20.6; p < 0.001), isolation of enterococci (OR, 4.8; 95% CI, 1.4-15.7; p = 0.010), and prior surgery due to infection before the one-stage hip revision (OR, 3.6; 95% CI, 2.0-6.4; p < 0.001). The factors associated with reinfection including both new and persistent infections were prolonged wound drainage (OR, 6.9; 95% CI, 2.2-21.5; p = 0.001) and prior surgery due to infection (OR, 4.3; 95% CI, 1.9-9.5; p < 0.001). Prolonged wound drainage after the one-stage revision arthroplasty for PJI of the hip must be treated rigorously. Patients with a history of a prior surgical procedure due to hip infection should be informed about the risk of further re-revision when deciding for the one-stage exchange. In case of enterococcal isolation, surgeons may consider another treatment approach rather than the one-stage exchange. Furthermore, we recommend the use of dual mobility cups when performing the one-stage revision hip arthroplasty to reduce the risk of dislocation.Level of Evidence Level III, therapeutic study.

Synovial Fluid Viscosity Test is Promising for the Diagnosis of Periprosthetic Joint Infection

BackgroundSo far there is no “gold standard” test for the diagnosis of periprosthetic joint infection (PJI), compelling clinicians to rely on several serological and synovial fluid tests with no 100% accuracy. Synovial fluid viscosity is one of the parameters defining the rheology properties of synovial fluid. We hypothesized that patients with PJI may have a different level of synovial fluid viscosity and aimed to investigate the sensitivity and specificity of synovial fluid viscosity in detecting PJI. MethodsThis prospective study was initiated to enroll patients undergoing primary and revision arthroplasty. Our cohort consisted of 45 patients undergoing revision for PJI (n = 15), revision for aseptic failure (n = 15), and primary arthroplasty (n = 15). PJI was defined using the Musculoskeletal Infection Society criteria. In all patients, synovial fluid viscosity, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and plasma d-dimer levels were measured preoperatively. ResultsThe synovial fluid viscosity level was significantly lower (P = .0011) in patients with PJI (7.93 mPa·s, range 3.0-15.0) than in patients with aseptic failure (13.11 mPa·s, range 6.3-20.4). Using Youden’s index, 11.80 mPa·s was determined as the optimal threshold value for synovial fluid viscosity for the diagnosis of PJI. Synovial fluid viscosity outperformed CRP, ESR, and plasma d-dimer, with a sensitivity of 93.33% and a specificity of 66.67%. ConclusionSynovial fluid viscosity seems to be on the same level of accuracy with CRP, ESR, and d-dimer regarding PJI detection and to be a promising marker for the diagnosis of PJI.

Outcome of short versus long interval in two-stage exchange for periprosthetic joint infection: a prospective cohort study.

A two-stage exchange is the standard treatment approach for chronic periprosthetic joint infection (PJI). While a 6-8week interval is commonly used before reimplantation, the optimal length of the prosthesis-free interval has not yet been determined. We evaluated the influence of a short (< 4weeks) and long (≥ 4weeks) interval on reinfection rate and functional outcome of hip and knee PJI. In this prospective cohort, patients undergoing two-stage revision for PJI were assigned to prosthesis reimplantation after a short (< 4weeks) or long (≥ 4weeks) interval. All patients received standardized antimicrobial therapy, which consisted of antibiogram-adapted, non-biofilm-active antibiotics during the interval and an antimicrobial combination therapy with biofilm-active antibiotics after reimplantation. Follow-up was performed for infection, joint function, pain, need for care and quality of life. Thirty-eight patients undergoing two-stage revision for PJI (18 hips and 20 knees) were included. Short interval was used in 19 patients having a mean interval of 17.9days (range 7-27days), long interval in 19 patients having a mean interval of 63.0days (range 28-204days). At a mean follow-up of 39.5months (range 32-48months), 37 of 38 patients (97.4%) were infection-free. One failure occurred among patients with long interval and none among patients with short interval. Functional results (ROM, HHS, KSS, VAS) and quality of life (SF-36) were similar in both groups. Patients treated with long interval required cumulatively additional 204 inpatient days for nursing care compared to patients with short interval. This study suggests that two-stage exchange with short interval has a similar outcome than with long interval, when highly active antibiotic therapy is used. Patient inconvenience and care costs due to immobilization were lower when strategies with a short interval were used.

Do Trabecular Metal Acetabular Components Reduce the Risk of Rerevision After Revision THA Performed for Periprosthetic Joint Infection? A Study Using the NJR Data Set.

A single-center study of 144 THAs revised specifically for periprosthetic joint infection (PJI) observed that trabecular metal (TM) acetabular components had a reduced risk of rerevision for subsequent infection compared with non-TM implants. It was suggested that TM was protective against infection after revision and that TM may be useful when revising THAs for PJI. Three registry studies have subsequently assessed the effect of TM on future infection. In the National Joint Registry (NJR) for England and Wales, we earlier reported lower revision rates for infection when TM (versus non-TM) was used in primary THA, but no difference in rerevision rates for infection when TM was used for all-cause revision THAs. The latter findings in all-cause revisions were also confirmed in a study from the Swedish and Australian registries. It is possible that TM only reduces the risk of infection when it is specifically used for PJI revisions (rather than all-causes). However, to date, the registry analyses have not had large enough cohorts of such cases to assess this meaningfully. (1) In revision THAs performed for PJI, are rerevision rates for all-cause acetabular indications lower with TM acetabular components compared with non-TM designs? (2) In revision THAs performed for PJI, are rerevision rates of any component for infection lower with TM acetabular components compared with non-TM designs? A retrospective observational study was performed using NJR data from England and Wales, which is the world's largest arthroplasty registry and contains details of over two million joint replacement procedures. The registry achieves high levels of patient consent (92%) and linked procedures (ability to link serial procedures performed on the same patient and hip; 94%). Furthermore, recent validation studies have demonstrated that when revision procedures have been captured within the NJR, the data completion and accuracy were excellent. Of 11,988 revisions performed for all causes, 794 were performed for PJI in which the same cementless acetabular component produced by one manufacturer was used. Acetabular components were either TM (n = 541) or non-TM (n = 253). At baseline the two groups were comparable for sex, age, body mass index, and American Society of Anesthesiologists (ASA) grade. Outcomes after revision THA (rerevision for all-cause acetabular indications and rerevision of any component for infection) were compared between the groups using Fine and Gray regression analysis, which considers the competing mortality risk. Regression models were adjusted for the propensity score, with this score summarizing many of the potential patient and surgical confounding factors (age, sex, ASA grade, surgeon grade, approach, and type of revision procedure performed). There was no difference in 5-year cumulative acetabular component survival rates between TM (96.3%; 95% confidence interval [CI], 94%-98%) and non-TM components (94.4%, 95% CI, 90%-97%; subhazard ratio, 0.78, 95% CI, 0.37-1.65; p = 0.509). There was no difference in 5-year cumulative implant survival rates free from infection between TM (94.8%; 95% CI, 92%-97%) and non-TM components (94.4%, 95% CI, 90%-97%; subhazard ratio, 0.97, 95% CI, 0.48-1.96; p = 0.942). We found no evidence to support the notion that TM acetabular components used for PJI revisions reduced the subsequent risk of all-cause rerevision or the risk of rerevision for infection compared with non-TM implants from the same manufacturer. We therefore advise caution against recent claims that TM components may protect against infection. Level III, therapeutic study.

Tests for predicting reimplantation success of two-stage revision for periprosthetic joint infection: A systematic review and meta-analysis.

Several tests are used before reimplantation to detect persistent infection in patients with periprosthetic joint infection (PJI) undergoing two-stage revision. However, there is no consensus as to the optimal tests for excluding persistent infection or predicting successful reimplantation by stage. We aimed to determine the accuracy of different tests used to detect persistent infection after the first stage, and/or predicting failure following reimplantation in patients with PJI. We conducted a systematic review and meta-analysis of PubMed, Embase and the Cochrane Library databases. Two reviewers independently conducted quality assessments and data extractions to estimate pooled sensitivity and specificity, diagnostic odds ratio and area under the receiver operating characteristic curves (AUSROC) for each test. We included 24 studies published between May 1999 and September 2017. Synovial fluid polymorphonuclear neutrophils (PMN)% had the highest sensitivity of 0.70, followed by serum erythrocyte sedimentation rate (0.57) and spacer sonication fluid culture (0.53). Synovial fluid culture had the highest specificity of 0.97, followed by frozen section (0.93) and the Musculoskeletal Infection Society criteria (0.92). Spacer sonication fluid culture was the most accurate test with an AUSROC of 0.8089, followed by synovial fluid culture (0.7749) and frozen section (0.7819). Spacer sonication fluid culture had a relatively high diagnostic accuracy. We emphasize that no test can be used alone to exclude persistent infection beyond the first stage and/or predict failed reimplantation beyond the second stage. II, systematic review and meta-analysis of level 2 to level 4 studies with inconsistent results.

Results and Patient Reported Outcome Measures (PROMs) after One-Stage Revision for Periprosthetic Joint Infection of the Hip: A Single-centre Retrospective Study.

Background: Little is known about functional outcome and quality of life (QoL) after one-stage revision for periprosthetic joint infection (PJI) of the hip.Methods: a cohort of 30 subjects treated with one-stage revision between 2011 and 2015 was identified, and questionnaires on functional outcome and QoL were distributed.Results: 28 subjects were successfully treated (93%). Most subjects were referred from other hospitals. Coagulase-negative Staphylococcus was found in 50% of the cases, and 40% of all cultured bacteria were multidrug-resistant. 25% had subsequent revision surgery, unrelated to PJI. Functional outcome was good and QoL scores were high, comparable to prosthetic joint revision surgery in general.Conclusion: Although the cohort was small and statistical analysis was not performed, this study showed that excellent results can be obtained with one-stage revision for hip PJI. Functional outcome and QoL was comparable to prosthetic joint revision surgery in general.

Vancomycin-Loaded Polymethylmethacrylate Spacers Fail to Eradicate Periprosthetic Joint Infection in a Clinically Representative Mouse Model.

Periprosthetic joint infection (PJI) remains a devastating complication following total joint arthroplasty. Current animal models of PJI do not effectively recreate the clinical condition and thus provide limited help in understanding why treatments fail. We developed a mouse model of the first-stage surgery of a 2-stage revision for PJI involving a 3-dimensionally printed Ti-6Al-4V implant and a mouse-sized cement spacer that elutes vancomycin. Vancomycin was mixed with polymethylmethacrylate (PMMA) cement and inserted into custom-made mouse-sized spacer molds. Twenty C57BL/6 mice received a proximal tibial implant and an intra-articular injection of 3 × 10 colony-forming units of Staphylococcus aureus Xen36. At 2 weeks, 9 mice underwent irrigation and debridement of the leg with revision of the implant to an articulating vancomycin-loaded PMMA spacer. Postoperatively, mice underwent radiography and serum inflammatory-marker measurements. Following euthanasia of the mice at 6 weeks, bone and soft tissues were homogenized to quantify bacteria within periprosthetic tissues. Implants and articulating spacers were either sonicated to quantify adherent bacteria or examined under scanning electron microscopy (SEM) to characterize the biofilm. Vancomycin-loaded PMMA spacers eluted vancomycin for ≤144 hours and retained antimicrobial activity. Control mice had elevated levels of inflammatory markers, radiographic evidence of septic loosening of the implant, and osseous destruction. Mice treated with a vancomycin-loaded PMMA spacer had significantly lower levels of inflammatory markers (p < 0.01), preserved tibial bone, and no intra-articular purulence. Retrieved vancomycin-loaded spacers exhibited significantly lower bacterial counts compared with implants (p < 0.001). However, bacterial counts in periprosthetic tissue did not significantly differ between the groups. SEM identified S. aureus encased within biofilm on control implants, while vancomycin-loaded spacers contained no bacteria. This animal model is a clinically representative model of PJI treatment. The results suggest that the antimicrobial effects of PMMA spacers are tightly confined to the articular space and must be utilized in conjunction with thorough tissue debridement and systemic antibiotics. These data provide what we believe to be the first insight into the effect of antibiotic-loaded cement spacers in a clinically relevant animal model and justify the adjunctive use of intravenous antibiotics when performing a 2-stage revision for PJI.

One- and two-stage surgical revision of peri-prosthetic joint infection of the hip: a pooled individual participant data analysis of 44 cohort studies

One-stage and two-stage revision strategies are the two main options for treating established chronic peri-prosthetic joint infection (PJI) of the hip; however, there is uncertainty regarding which is the best treatment option. We aimed to compare the risk of re-infection between the two revision strategies using pooled individual participant data (IPD). Observational cohort studies with PJI of the hip treated exclusively by one- or two-stage revision and reporting re-infection outcomes were retrieved by searching MEDLINE, EMBASE, Web of Science, The Cochrane Library, and the WHO International Clinical Trials Registry Platform; as well as email contact with investigators. We analysed IPD of 1856 participants with PJI of the hip from 44 cohorts across four continents. The primary outcome was re-infection (recurrence of infection by the same organism(s) and/or re-infection with a new organism(s)). Hazard ratios (HRs) for re-infection were calculated using Cox proportional frailty hazards models. After a median follow-up of 3.7 years, 222 re-infections were recorded. Re-infection rates per 1000 person-years of follow-up were 16.8 (95% CI 13.6–20.7) and 32.3 (95% CI 27.3–38.3) for one-stage and two-stage strategies respectively. The age- and sex-adjusted HR of re-infection for two-stage revision was 1.70 (0.58–5.00) when compared with one-stage revision. The association remained consistently absent after further adjustment for potential confounders. The HRs did not vary importantly in clinically relevant subgroups. Analysis of pooled individual patient data suggest that a one-stage revision strategy may be as effective as a two-stage revision strategy in treating PJI of the hip.

Two-stage revision for periprosthetic joint infection of the hip: Culture-negative versus culture-positive infection

IntroductionNegative culture findings are common in periprosthetic joint infection (PJI) of the hip. MethodsRetrospective study was performed to total 84 patients which devided into two groups: culture-negative (n: 27) and culture-positive (n: 57). ResultsThe reimplantation rate was 96.3% and 91.2% in the culture-negative and culture-positive groups, respectively. The overall infection control rate was 92.6% and 82.4% in the culture-negative and culture-positive groups, respectively. ConclusionTwo-stage revision resulted a comparable outcome for the treatment of culture-negative periprosthetic joint infection of the hip compared to the culture-positive group

Serum D-Dimer Test Is Promising for the Diagnosis of Periprosthetic Joint Infection and Timing of Reimplantation.

Despite the availability of a battery of tests, the diagnosis of periprosthetic joint infection (PJI) continues to be challenging. Serum D-dimer assessment is a widely available test that detects fibrinolytic activities that occur during infection. We hypothesized that patients with PJI may have a high level of circulating D-dimer and that the presence of a high level of serum D-dimer may be a sign of persistent infection in patients awaiting reimplantation. This prospective study was initiated to enroll patients undergoing primary and revision arthroplasty. Our cohort consisted of 245 patients undergoing primary arthroplasty (n = 23), revision for aseptic failure (n = 86), revision for PJI (n = 57), or reimplantation (n = 29) or who had infection in a site other than a joint (n = 50). PJI was defined using the Musculoskeletal Infection Society criteria. In all patients, serum D-dimer level, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level were measured preoperatively. The median D-dimer level was significantly higher (p < 0.0001) for the patients with PJI (1,110 ng/mL [range, 243 to 8,487 ng/mL]) than for the patients with aseptic failure (299 ng/mL [range, 106 to 2,571 ng/mL). Using the Youden index, 850 ng/mL was determined as the optimal threshold value for serum D-dimer for the diagnosis of PJI. Serum D-dimer outperformed both ESR and serum CRP, with a sensitivity of 89% and a specificity of 93%. ESR and CRP had a sensitivity of 73% and 79% and a specificity of 78% and 80%, respectively. The sensitivity and specificity of ESR and CRP combined was 84% (95% confidence interval [CI], 76% to 90%) and 47% (95% CI, 36% to 58%), respectively. It appears that serum D-dimer is a promising marker for the diagnosis of PJI. This test may also have a great utility for determining the optimal timing of reimplantation. Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Single-stage revision for chronic periprosthetic joint infection of the knee: a minimum 4-year follow-up

Background: Periprosthetic joint infection (PJI) is one of the most challenging and frequent complications after hip and knee arthroplasty. This study aimed to determine whether chronic PJI patients who had undergone single-stage knee revision: (I) achieved adequate infection control as assessed by culture of synovial fluid and monitoring of inflammatory markers; (II) regained normal knee function as assessed by the Knee Society Score (KSS). Methods: We retrospectively reviewed 43 patients who had undergone single-stage revision for PJI after total knee arthroplasty (TKA) between April 2005 and October 2011. The most recent follow-up was in October 2014, and the minimum follow-up was 4 years (range, 4–10 years). Results: Participants were 27 men and 16 women with a mean age of 65 years (range, 37–80 years). Infection was controlled by the time of last follow-up in 41 of 43 patients; one patient died for reasons unrelated to infection after completing the 4-year follow-up, one patient had recurrence of PJI that was eradicated by prosthesis removal and second-stage revision, and one patient had a recurrent fungal infection that was controlled by intravenous vancomycin, intra-articular fluconazole, and oral fluconazole. The mean preoperative KSS score was 33.6 (range, 0–61), which had increased significantly by the last follow-up to 63.9 (range, 43–82) points. Conclusions: Single-stage revision for chronic knee PJI achieved a high rate of infection control and acceptable functional outcomes; this is a more convenient alternative that avoids the risks associated with two operations and hospitalizations. Level of Evidence: Level 4, therapeutic study.

Viable bacteria persist on antibiotic spacers following two-stage revision for periprosthetic joint infection.

Treatment in periprosthetic joint infection (PJI) remains challenging. The failure rate of two-stage revision and irrigation and debridement with component retention in PJI suggests that biofilm cells have a high tolerance to antibiotic chemotherapy. Previous work has demonstrated that biofilm cells have high antibiotic tolerance in vitro, but there is little clinical evidence to support these observations. The aim of this study was to determine if retrieved antibiotic spacers from two-stage revision total knee arthroplasty for PJI have evidence of remaining viable bacteria. Antibiotic poly (methyl methacrylate) (PMMA) spacers from two-stage revision total knee arthroplasty for PJI were prospectively collected and analyzed for bacterial 16s rRNA using polymerase chain reaction (PCR), reverse transcription (RT)-PCR, quantitative RT-PCR (qRT-PCR), and single genome analysis (SGA). PCR and RT-PCR identified bacterial species on 53.8% (7/13) of these samples. When initial culture negative cases are excluded, 68% (6/9) samples were identified with bacterial species. A more rigorous qRT-PCR analysis showed a strong positive signal for bacterial contamination in 30.7% (4/13) of cases. These patients did not show any clinical evidence of PJI recurrence after 15 months of follow-up. Because the half-life of bacterial rRNA is approximately a few days, the identification of bacteria rRNA on antibiotic PMMA spacers suggests that viable bacteria were present after conclusion of antibiotic therapy. This study provides evidence for the high tolerance of biofilm cells to antibiotics in vivo and the important role of bacterial persisters in PJI. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:452-458, 2018.

ESR and CRP are useful between stages of 2-stage revision for periprosthetic joint infection.

BackgroundSerum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are important tests in the initial diagnosis of periprosthetic joint infection. Many surgeons also use these tests to determine if infection has resolved between stages of a 2-stage procedure, but little data exist regarding this practice.MethodsA retrospective review of our institutional total joint databases was conducted to determine sensitivity, specificity, and predictive values of elevated ESR and/or CRP to diagnose persistent infection between stages.ResultsAmong 16 knees and 5 hips, sensitivity was 50% for CRP, 75% for ESR, and 100% when combined. The negative predictive value of persistent infection was 100% when neither test was elevated.ConclusionsResults of this study support the use of CRP and ESR as indicators of the resolution of periprosthetic joint infection between stages of 2-stage revision.

Do articulating spacers or static spacers have more effect on the mental health status of patients undergoing two-stage revision total knee arthroplasty for periprosthetic joint infection?

Background: There are several studies that have focused on functional outcome and rate of recurrent infection for patients undergoing two-stage revision total knee arthroplasty (TKA) for the treatment of periprosthetic joint infection (PJI). However, there are very few studies assessing the mental health status of these patients, which is why we conducted a study to assess and compare the mental health status between patients who underwent first-stage revision with a static spacer and those who had an articulating spacer. Our hypothesis was that the patients with articulating spacers have a lesser degree of mental stress than those with static spacers. Methods: From 2011 to 2013, a total of 40 knees with a diagnosis of PJI were treated with a standard two-stage revision TKA. Hospital anxiety and depression scale (HADS)-A and D, Visual Analogue Scale (VAS), Short-form-36 mental health (SF-36) scores were compared between groups preoperatively and 4 weeks postoperatively. Results: There were no significant differences between the two groups. Similarly, P value did not show any significant differences between the groups for both VAS and SF-36 score even though it was significant within the groups for VAS score preoperatively and postoperatively (P&lt;0.0001). Conclusions: Both articulating and static spacers significantly reduced the psychological stress on the patients undergoing two-stage revision for PJI. Based on our results, we concluded that improvement in mental health status of both articulating and static spacer groups were comparable with no statistically significant differences.

Validation of the diagnosis 'prosthetic joint infection' in the Danish Hip Arthroplasty Register.

The purpose of this study was to validate the diagnosis of periprosthetic joint infection (PJI) in the Danish Hip Arthroplasty Register (DHR). We identified a cohort of patients from the DHR who had undergone primary total hip arthroplasty (THA) since 1 January 2005 and followed them until first-time revision, death, emigration or until 31 December 2012. Revision for PJI, as registered in the DHR, was validated against a benchmark which included information from microbiology databases, prescription registers, clinical biochemistry registers and clinical records. We estimated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PJI in the DHR alone and in the DHR when combined with microbiology databases. In total, 1382 of the 37 826 primary THAs in the DHR were registered as having been revised for any cause once 26 patients with errors in registration had been excluded: 232 of these were for PJI. For this group, the sensitivity was 67%, specificity 95%, PPV 77%, and NPV 92%. Combining the data from the DHR with those from microbiology databases increased the sensitivity to 90% and also improved specificity (100%), PPV (98%) and NPV (98%). Only two thirds of revisions for PJI were captured in the DHR and only 77% of the PJI reported to the DHR could be confirmed to be infected. combining the data from the DHR with those from microbiology databases substantially improved the validity of the diagnosis of PJI and should enable future register-based studies.

Reduction of Treatment Duration in Periprosthetic Infection with a Fast-Track Concept Is Economically Not Feasible

In the two stage revision of periprosthetic joint infection (PJI), the prosthesis-free interval may be reduced to 2-3 weeks (fast-track). This is an innovative approach with clear advantages for both the patient and health insurance stakeholders. The prosthesis-free interval with conventional two-stage PJI slow-track procedures lasts 6-12 weeks. In Germany, the patient spends this time either at home or in a geriatric hospital. This period is mainly used to manage infections. The patient is then readmitted for implantation of the revision prosthesis. This readmission then leads to additional reimbursement, as this is formally a new insurance case. Despite this double payment, the costs for the treatment of such complex diseases are not covered by the German DRG system. If hospitals are to implement the proven fast-track concept, they need to invest in a multidisciplinary medical team. This would be responsible for defining infections, selecting patients, and improving diagnosis and antimicrobial therapy and should thus improve the rates of cure of infections. However, the G-DRG reimbursement system treats the two surgeries as a single case, providing that less than 30 days lies between the two interventions; as a result, the reimbursement is inadequate for patients with the fast-track interval. We analysed the theoretical financial deficit for a hospital and describe the cost-saving potential for payers applying the fast-track interval rather than the slow-track approach in selected PJI patients, using a comprehensive and individualised treatment concept. Our analysis covered thirty-two consecutive patients with infected joint prosthesis (17 hips, 15 knee) admitted to our hospital from January 2011 to December 2012 undergoing a two-stage exchange (ICD-10-GM: T84.5). We excluded patients who underwent only one hospital admission during the analysed time frame or who were admitted to another hospital. Patients treated with joint fusion and patients who died were also excluded. A retrospective simulation of the DRG reimbursement was then performed according to the German Hospital Fees Act (§ 21 KHEntgG) for the two-stage fast-track interval concept. Due to the retrospective character, we could not analyse detailed financial differences specifically related to the fast-track treatment, such as the cost for biofilm active antimicrobial drugs and savings for outpatient care during the long interval in slow-track. We did not consider hospital investment costs for establishing an interdisciplinary medical team, and were only able to roughly describe the cost saving potential and benefits on a societal perspective. With the fast-track concept, the DRG receipts were reduced by a mean of 10 831 € per patient, which was higher for hip prostheses than for knee prostheses. Even though fast-track treatment cost 1159 € less than slow-track treatment, the hospital lost 8498 € per fast-track patient, because of the loss of the second surgery reimbursement. For each fast-track patient, the payers save one G-DRG reimbursement plus the costs for any care during the prosthesis-free interval, as occurred in the slow-track. Fast-track patients benefit from the reduced period of functional treatment, of about 10 weeks. The current G-DRG reimbursement system paradoxically rewards slow-track intervals for two-stage revisions and jeopardizes the implementation of beneficial fast-track intervals in clinical routine. Patients treated with slow-track therapy experience longer and more debilitating treatment, accompanied by greater healthcare costs for both payers and hospitals. New treatment concepts which offer better care at lower cost should attract the attention of policy makers, clinicians, and the public.