Periprosthetic Joint Infection In Patients Research Articles

Prior staphylococcal bacteremia and risk of surgical site infection after total joint arthroplasty: a nested case-control study

Background: Staphylococcus species can become dormant, causing recurrent infection after long latent periods. We sought to determine surgical site infection (SSI) risk after knee, hip, or shoulder arthroplasty with a history of staphylococcal bacteremia. Methods: Data on 7604 patients who underwent primary or revision knee, hip, or shoulder arthroplasty were reviewed. Twenty-four cases of prior documented staphylococcal bacteremia were identified. These cases were matched 1:4 to controls with similar procedures, surgical indications, and medical comorbidities. Conditional logistic regression was used to determine the risk of SSI due to prior bacteremia relative to medically similar controls. Results: Staphylococcal isolates at the time of most recent bacteremia were methicillin-sensitive S. aureus (MSSA)( 9/24), methicillin-resistant S. aureus (MRSA)(8/24), and methicillin-resistant S. epidermidis (MRSE)(7/24). Prior patients with bacteremia who developed subsequent SSI (46%, 11/24 patients) all presented within 6 mo (mean 32.0 days IQR 10-142) with deep infection and positive perarticular tissue or synovial aspirate cultures. The conditional odds ratio (cOR) for SSI among prior bacteremia patients was greater than 7-fold that of controls (cOR 7.28 CI 2.21, 24.1; P<0.001). Among prior native or periprosthetic joint infection patients, prior bacteremia did not significantly increase recurrent SSI risk after two-stage arthroplasty (cOR 1.52 CI 0.29, 7.94 P=0.62). Among patients without prior joint infections, bacteremia significantly elevated future SSI risk (cOR 28.0 CI 3.44, 227, P=0.002). Conclusions: A history of staphylococcal bacteremia poses a significantly elevated risk of deep infection after hip, knee, or shoulder arthroplasty in patients without a prior native or periprosthetic joint infection.

Utility of Serological Markers for Detecting Persistent Infection in Two-Stage Revision Arthroplasty in Patients With Inflammatory Arthritis

BackgroundSerum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are commonly used for the diagnosis of persistence of infection after the first stage of 2-stage revision arthroplasty for periprosthetic joint infection (PJI). As both ESR and CRP are markers of systemic inflammation, the utility of these tests to monitor infection clearance in patients with inflammatory arthritis is unclear. MethodsFrom 2001 to 2016, 44 two-stage revision total hip or knee arthroplasties in patients with an inflammatory arthritis diagnosed by a rheumatologist were identified. Persistence of infection at the time of planned second stage was defined as satisfying the Musculoskeletal Infection Society criteria for PJI (14 infected, 30 noninfected). ESR and CRP values were compared between the stages using nonparametric tests. Receiver operating characteristic analysis was performed to obtain the diagnostic parameters. ResultsESR and CRP decreased between the stages in the noninfected group (ESR: mean decrease = 31.6 mm/h [19.2-44.0], P < .001; CRP: mean decrease = 5.2 mg/dL [2.1-8.2], P < .001), but remained elevated in the infected group (ESR: mean decrease = 7.7 [−23.1 to 36.6], P = .572; CRP: mean decrease = 1.5 [−2.2 to 5.1], P = .258). Optimal thresholds for persistent infection were 29.5 mm/h and 2.8 mg/dL, respectively, for ESR and CRP. The sensitivity and specificity at the optimal thresholds were 64% and 77% for ESR, and 64% and 90% for CRP. ConclusionESR and CRP responded to the treatment of PJI in patients with inflammatory arthritis and had reasonably high specificities with moderate sensitivities. ESR and CRP appear to be useful tools in diagnosing persistent infection even in patients with inflammatory arthritis.

Are All Periprosthetic Joint Infections the Same? Evaluating Major vs Minor Criteria

BackgroundThe diagnosis of periprosthetic joint infection (PJI) can be made when 1 major criterion or 3 of 5 minor criteria are present. However, the outcomes of patients with a major vs minor criteria for diagnosis have not been studied. The objective of this study was to evaluate if a difference in outcome of surgical intervention existed between patients with PJI who were diagnosed with a major criterion or a combination of minor criteria. MethodsA retrospective chart review identified 277 primary total hip or knee arthroplasty patients who had developed PJI based on the International Consensus Meeting definition. Patients were further stratified into “major” vs “minor” groups. Patient demographics, PJI workup, surgical treatment, microbiological growth, and clinical outcomes were recorded. Treatment success was defined by using the Delphi criteria. Standard statistical analysis was performed. ResultsOverall, 34 patients met minor-only criteria (12.2%), whereas 243 met major criteria. Of the minor-only patients, 16 (47%) were culture negative. When controlling for confounding variables, there was no statistically significant difference with regard to treatment success (minor 94.1% vs major 82.3%, P = .085) between groups at final follow-up (mean 110 months, range 2.3-567 months). Only higher Charlson comorbidity index (P = .001) and an initial 2-stage surgical procedure (P = .003) were associated with decreased treatment success. ConclusionPJI patients were similar between both criteria groups, and there was no difference in treatment success as defined by the Delphi criteria between minor-only PJI and major criteria PJI patients.

Rate and Risk Factors for Periprosthetic Joint Infection Among 36,494 Primary Total Hip Arthroplasties

BackgroundAs periprosthetic joint infections (PJIs) can have tremendous health and socioeconomic implications, recognizing patients at risk before surgery is of great importance. Therefore, we sought to determine the rate of and risk factors for deep PJI in patients undergoing primary total hip arthroplasty (THA). MethodsClinical characteristics of patients treated with primary THA between January 1999 and December 2013 were retrospectively reviewed. These included patient demographics, comorbidities (including the Charlson/Deyo comorbidity index), length of stay, primary diagnosis, total/allogeneic transfusion rate, and in-hospital complications, which were grouped into local and systemic (minor and major). We determined the overall deep PJI rate, as well as the rates for early-onset (occurring within 2 years after index surgery) and late-onset PJI (occurring more than 2 years after surgery). A Cox proportional hazards regression model was constructed to identify risk factors for developing deep PJI. Significance level was set at 0.05. ResultsA deep PJI developed in 154 of 36,494 primary THAs (0.4%) during the study period. Early onset PJI was found in 122 patients (0.3%), whereas late PJI occurred in 32 patients (0.1%). Obesity, coronary artery disease, and pulmonary hypertension were identified as independent risk factors for deep PJI after primary THA. ConclusionThe rate of deep PJIs of the hip is relatively low, with the majority occurring within 2 years after THA. If the optimization of modifiable risk factors before THA can reduce the rate of this complication remains unknown, but should be attempted as part of good practice.

Daptomycin treatment in patients with resistant staphylococcal periprosthetic joint infection\xa0

BackgroundResistant staphylococcal organisms remain a serious problem in the treatment of periprosthetic joint infection (PJI). Higher failure rates have been reported when vancomycin was used. The purpose of this study was to assess the clinical dosage, effect, and safety of daptomycin in patients with resistant staphylococcal PJI.MethodsWe retrospectively enrolled patients with hip or knee PJI who were treated with daptomycin in our institution (n = 16) from January 2013 to December 2014 with a minimum follow-up of 2 years. The patients received daptomycin when glycopeptide could not be used due to multiple resistance, any adverse reaction, chronic kidney disease stage 3 or worse, and previous treatment failure with glycopeptide or empirical therapy.ResultsThese patients received daptomycin at a median dose of 8.3 mg∕kg per day for a median duration of 14 days. The overall treatment success rate was 87.5% (14 of 16 cases) after a median follow-up period of 27 months. In the subgroups of acute and chronic PJI, the success rate was 80% and 91%, respectively. One patient developed asymptomatic transient serum aspartate transaminase (AST) elevation. No severe side effects such as myositis, acute renal failure due to rhabdomyolysis or eosinophilic pneumonia were found in our series.ConclusionRelatively high daptomycin doses combined with adequate surgical intervention were effective in treating resistant staphylococcal PJI. Daptomycin is an option worthy of consideration in PJI patients for whom glycopeptide treatment is unsuitable. Further prospective randomized comparative study is needed in the future.

Risk of Periprosthetic Joint Infection in Patients With Multiple Arthroplasties

BackgroundRisk of subsequent periprosthetic joint infection (PJI) in a second prosthetic joint following initial PJI has been shown to be 19%-20%. We sought to identify (1) the risk of developing a second PJI for our patients with multiple prosthetic joints and (2) the effect of bacteremia on development of a subsequent PJI. MethodsWe retrospectively reviewed all patients treated surgically for PJI by a single surgeon from 2003 to 2014. Time between initial and subsequent infection, bacteremia, and risk factors for PJI were identified. ResultsOf 167 patients treated for PJI, 76 had multiple prosthetic joints. Thirteen percent (10/76) developed a PJI in a second location. Excluding simultaneous infections, the rate was 8.3% (6/72), despite having a 57% incidence of immunosuppression, diabetes, renal failure, smoking, or steroid use. Average follow-up for patients with 1 PJI was 4.6 years (range 0.03-13.6). Seventy percent (7/10) of patients with multiple infections were bacteremic at the time of initial infection compared to 18.1% (12/66) of patients with a single infection (P = .0004). Excluding the 4 simultaneous infections (all bacteremic), the risk of developing an infection in a second joint was 20% if bacteremic and 5.2% if not bacteremic. ConclusionOur study identified the risk of developing a subsequent PJI to be one half of previous studies. Bacteremia at the time of PJI is an important factor for developing subsequent PJI. Multiple prosthetic joints may be less hazardous than previously thought for patients with PJI suggesting that suppressive antibiotics may only be necessary in cases with bacteremia.

Positive Blood Cultures in Periprosthetic Joint Infection Decrease Rate of Treatment Success

BackgroundBlood cultures are often obtained at the time of periprosthetic joint infection (PJI) diagnosis yet they are not considered part of the diagnostic criteria and the effects of a positive result on surgical outcome are unknown. The purposes of this study are to characterize the use of blood cultures when diagnosing PJI and to determine the association of positive blood cultures with PJI treatment success. MethodsA retrospective chart review on 320 patients surgically treated for primary hip and knee PJIs was performed from 2006-2013 at 2 academic medical centers with minimum 12-month follow-up. Treatment success was defined by the Delphi criteria. Multiple logistic regression analysis was performed to identify variables associated with treatment success. ResultsBlood cultures were obtained from 53.1% of PJI patients (170/320) at the time of diagnosis. The same organism was identified 86.0% of the time in blood culture and operative culture. Patients with positive blood cultures at the time of PJI diagnosis had elevated synovial white blood cell count (98,979, P = .012), elevated serum C-reactive protein (24.2 mg/L, P < .001), and decreased treatment success (65.1%) compared with those with a negative blood culture (85.0%) and those without a blood culture (82.7%, P = .013). A positive blood culture remained associated with decreased PJI treatment success using multiple logistic regression analysis. ConclusionThe presence of positive blood cultures at the time of PJI diagnosis decreased PJI treatment success. Further prospective studies are needed to help identify the role of blood cultures in the work up of PJI and treatment optimization in these patients.

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.

Neer Award 2015: Analysis of cytokine profiles in the diagnosis of periprosthetic joint infections of the shoulder

Periprosthetic joint infection (PJI) after shoulder arthroplasty can present a diagnostic and therapeutic challenge. This study evaluated the diagnostic utility of broader synovial fluid cytokine analysis for identifying PJI in patients undergoing revision shoulder arthroplasty. Synovial fluid levels of 9 cytokines (interleukin [IL] 6, granulocyte-macrophage colony-stimulating factor, IL-1β, IL-12, IL-2, IL-8, interferon-γ, IL-10, and tumor necrosis factor-α) were measured in 75 cases of revision shoulder arthroplasty with a multiplex immunoassay. Cases were classified into infection categories and groups based on objective perioperative findings. Differences in cytokine levels among infection groups were evaluated. Receiver operating characteristic curves were used to assess the diagnostic utility of the individual synovial fluid cytokines and combinations of cytokines in determining infection status. Synovial IL-6, granulocyte-macrophage colony-stimulating factor, interferon-γ, IL-1β, IL-2, IL-8, and IL-10 were significantly elevated in cases of revision shoulder arthroplasty classified as infected. Individually, IL-6, IL-1β, IL-8, and IL-10 showed the best combination of sensitivity and specificity for predicting infection, and a combined cytokine model consisting of IL-6, tumor necrosis factor-α, and IL-2 showed better diagnostic test characteristics than any cytokine alone, with sensitivity of 0.80, specificity of 0.93,, positive and negative predictive values of 0.87 and 0.89, and positive and negative likelihood ratios of 12.0 and 0.21. Individual and combined synovial fluid cytokine analysis were both more effective than routine perioperative testing, such as serum erythrocyte sedimentation rate and C-reactive protein, in the diagnosis of PJI of the shoulder. Once validated, combined synovial fluid cytokine analysis could be used as a predictive tool to determine the probability of PJI in patients undergoing revision shoulder arthroplasty and better guide treatment.

In-Hospital Mortality in Patients With Periprosthetic Joint Infection

BackgroundWhile periprosthetic joint infection (PJI) has a huge impact on patient function and health, only a few studies have investigated its impact on mortality. The purpose of this large-scale study was to (1) determine the rate and trends of in-hospital mortality for PJI and (2) compare the in-hospital mortality rate of patients with PJI and those undergoing revision arthroplasty for aseptic failure and patients undergoing other nonorthopedic major surgical procedures. MethodsData from the Nationwide Inpatient Sample from 2002 to 2010 were analyzed to determine the risk of in-hospital mortality for PJI patients compared with aseptic revision arthroplasty. The Elixhauser comorbidity index was used to obtain patient comorbidities. Multiple logistic regression analyses were used to examine whether PJI and other patient-related factors were associated with mortality. ResultsPJI was associated with an increased risk (odds ratio, 2.05; P < .0001) of in-hospital mortality (0.77%) compared with aseptic revisions (0.38%). The in-hospital mortality rate of revision total hip arthroplasties with PJI was higher than those for interventional coronary procedures (1.22%; 95% confidence interval [CI], 1.20-1.24), cholecystectomy (1.13%; 95% CI, 1.11-1.15), kidney transplant (0.70%; 95% CI, 0.61-0.79), and carotid surgery (0.89%; 95% CI, 0.86-0.93). ConclusionPatients undergoing treatment for PJI have a 2-fold increase in in-hospital mortality for each surgical admission compared to aseptic revisions. Considering that PJI cases often have multiple admissions and that this analysis is by surgical admission, the risk of mortality will accumulate for every additional surgery. Surgeons should be cognizant of the potentially fatal outcome of PJI and the importance of infection control to reduce the risk of mortality.

Preoperative Hip Injections Increase the Rate of Periprosthetic Infection After Total Hip Arthroplasty

BackgroundIntraarticular injections are both diagnostic and therapeutic for patients with osteoarthritis. A potential risk of periprosthetic joint infection (PJI) after total hip arthroplasty (THA) may occur from direct inoculation and/or immune suppression by corticosteroids. Large population-level databases were used to evaluate hip injection on the 1-year rate of PJI in patients undergoing primary THA. MethodsState-level ambulatory surgery and inpatient databases for Florida and California (2005-2012) were used to identify primary THA patients with 1-year preoperative and postoperative windows to evaluate possible injections or PJI, respectively. Patients were grouped as no injection or as THA performed 6-12 months, 3-6 months, or 0-3 months after injection. Risk adjustment was performed with multivariable regression. ResultsA total of 173,958 patients were included; 5421 (3.1%) underwent THA after an injection: 1395 (1.1%) of patients after 6-12 months, 1863 patients after 3-6 months, and 2163 (1.2%) after 0-3 months. In the 0-3 month group, PJI was significantly increased at 3 months (1.58%, P = .015), 6 months (1.76%, P = .022), and 1 year (2.04%, P = .031) compared with the noninjection control group (1.04%, 1.21%, and 1.47%, respectively). There were no differences in the 3- to 6-month and 6- to 12-month injection groups. ConclusionThere is an increased risk of PJI when THA is performed within 3 months of hip injection. We recommend that patients and their surgeons consider delaying elective THA until 3 months after an injection to avoid this elevated risk of infection.

Risk of Reinfection After Treatment of Infected Total Knee Arthroplasty

BackgroundThe purpose of this study was to determine the incidence of subsequent reinfections after initial treatment of an infected total knee arthroplasty, identify risk factors leading to reinfection, and compare results among the varying treatment modalities. MethodsA total of 1,493,924 primary TKA patients were identified from the Medicare data between October 1, 2005, and December 31, 2011. Patients who encountered periprosthetic joint infection (PJI) after TKA were identified using International Classification of Diseases, Ninth Revision, Clinical Modification code 996.66. The risk of subsequent PJI was stratified based on the first-line treatment and compared between the various first-line treatment groups. ResultsA total of 16,622 patients (1.1%) were diagnosed with PJI. The Kaplan-Meier risk of PJI was 0.77% at 1 year and 1.58% at 6 years. Age (P < .001), Charlson score (P < .001), hospital control (P < .001), race (P = .036), census region (P = .031), gender (P < .001) were identified as risk factors for PJI. Of the PJI patients, 20.8% (n = 2806) were treated with incision and drainage (I&D), 15.9% (n = 2150) treated with I&D and liner exchange, 22.7% (n = 3069) treated with 1-stage revision, 39.7% (n = 5364) treated with 2-stage revision, and 0.98% (n = 132) treated with amputation. After first-line treatment, 26% of patients with PJI had a subsequent PJI. Patients undergoing I&D as a first-line treatment had the highest risk of reinfection, with risks of 28.2% at 1 year and 43.2% at 6 years. One-stage revision patients had 33.9% greater adjusted risk of reinfection than 2-stage revision patients (P < .001). ConclusionTwo-stage reimplantation, despite 19% recurrence, had the highest success rate. Given the higher failure rates of I&D and single-stage revisions, guidelines need to be established for their specific indications.

Diagnosing Infection in the Setting of Periprosthetic Fractures

BackgroundThe diagnosis of periprosthetic joint infection is particularly challenging in patients with periprosthetic fractures. The purpose of this study was to investigate the utility of commonly used diagnostic tests for periprosthetic joint infection in patients with a periprosthetic fracture. MethodsOf 121 patients treated with a periprosthetic fracture (97 hips, 24 knees, mean age: 72.9), 14 (11.6%) met Musculoskeletal Infection Society criteria for infection. Diagnostic variables were evaluated using logistic regression models for the prediction of infection and receiver operating characteristics curves. ResultsThe synovial white blood cell (WBC) count and differential were the best diagnostic tests, with good test performance (area under the curve, 84%) and optimal cutoffs of 2707 WBC/uL and 77% polymorphonuclear cells. The erythrocyte sedimentation rate and C-reactive protein were found to have overall lower test performance but remained relatively sensitive at standard cutoff values of 30 mm/h and 10 mg/L, respectively. ConclusionThe synovial fluid WBC count and differential are the best tests with optimal cutoff values that are similar to those used for patients without a periprosthetic fracture.

Same-Day Surgery Does Not Increase Deep Infection Risk in Bilateral Total Hip Arthroplasty Patients

BackgroundPatients with bilateral hip disease may undergo same-day or staged bilateral total hip arthroplasty (THA). Our purpose was to compare the odds and identify risk factors for deep periprosthetic joint infection (PJI) among patients undergoing same-day vs staged bilateral THA (within 1 year or more than 1 year apart). MethodsAdministrative data for patients subjected to same-day and staged bilateral THA between January 1999 and December 2013 were retrieved. Patients with subsequent PJI were identified. Mean follow-up was 112.6 months (range, 23-201). A logistic regression model was constructed to determine differences in odds for infection between groups and risk factors for PJI. ResultsWe identified 1808 patients treated with same-day bilateral THA, 2082 patients treated with staged THAs within 1 year, and 2760 patients treated with staged THAs more than 1 year apart. Patients treated with same-day procedures had similar odds for PJI compared to those treated with staged THAs within 1 year (odds ratio [OR] = 0.632, 95% confidence interval [CI] [0.203, 1.962]), or more than 1 year apart (OR = 1.391, 95% CI [0.516, 3.746]). Women had 66.1% lower odds for PJI than men (OR = 0.339, 95% CI [0.16, 0.72]). Patients with inflammatory arthritis had 632% higher odds for PJI than patients with degenerative arthritis (OR = 7.321, 95% CI [1.912, 28.028]). Allogeneic transfusion was associated with 166% higher odds for PJI (OR = 2.661, 95% CI [1.198, 5.911]). ConclusionSame-day bilateral THA is not associated with increased odds for PJI compared to staged procedures. Male gender, inflammatory etiology, and allogeneic transfusion are significant risk factors for PJI in patients undergoing same-day or staged bilateral THA.

Prospective Comparison of Blood Culture Bottles and Conventional Swabs for Microbial Identification of Suspected Periprosthetic Joint Infection

BackgroundEarly, accurate detection of infection is vital to successful treatment of periprosthetic joint infection (PJI). Currently, no “gold standard” diagnostic testing exists. The goal of this prospective study was to compare the efficacy of a blood culture bottle system (BCBS) to commonly used culture swabs in confirming PJI in patients with high clinical suspicion. MethodsPatients were selected for enrollment based on Musculoskeletal Infection Society guidelines for PJI. erythrocyte sedimentation rate and C-reactive protein were obtained before aspiration. Aspirated fluid was divided between BCBS, swab, and synovial fluid analysis. Forty-nine samples were analyzed. ResultsBCBS yielded 41 positive cultures vs 19 with swab (P < .0001), particularly with respect to Staphylococcus epidermidis. There were no false positive results in the BCBS group, using strict Musculoskeletal Infection Society guidelines. ConclusionBCBS increased identification of pathogens in lower extremity PJI, providing clinicians with a low-cost, broadly-applicable test.

Do Prior Intra-Articular Corticosteroid Injections or Time of Administration Increase the Risks of Subsequent Periprosthetic Joint Infections after Total Knee Arthroplasty?

Intra-articular injections of corticosteroids have been used as a treatment option for degenerative arthritis of the knee for short- to mid-term symptomatic pain relief for many decades. Recently, there have been studies that have reported increased risks of periprosthetic joint infections in patients who have received these injections. In this study, we evaluated the risk of superficial, deep, and overall rate of infections in 302 patients who had received intra-articular corticosteroid infiltration within 12 months before undergoing total knee arthroplasty (TKA) and compared them with a 1:1 matched cohort who had undergone TKA, but who did not have any prior corticosteroid knee injections. At a mean follow-up of approximately 3.5 years after TKA, there were no significant differences in the rate of superficial incisional infections (7 vs. 6 out of 302 patients), deep periprosthetic infections (3 vs. 6 out of 302 patients), and overall infections (10 vs. 12 out of 302 patients) in the two groups. In addition, no significant differences were found in the rate of deep infections when intra-articular corticosteroids were administered 10 weeks to 2 months, 2-4 months, 4-6 months, 6-12 months, and beyond 12 months before surgery. We concluded that intra-articular corticosteroid injections are safe and do not increase the rate of postoperative infections.

Increased Risk of Periprosthetic Joint Infections in Patients With Hypothyroidism Undergoing Total Joint Arthroplasty

BackgroundAlthough thyroxine has an important role in modulating the immune system, it has not been associated with periprosthetic joint infection. This study was conceived to examine the association between hypothyroidism and periprosthetic joint infection (PIJ). MethodsUsing an institutional database, the preoperative comorbidities of 32,289 total joint arthroplasties performed between 2000 and 2013 were identified using an International Classification of Diseases, Ninth Revision–based comorbidity index. ResultsIn the multivariate analysis, hypothyroidism was found to be an independent risk factor (adjusted odds ratio: 2.46; P < .0001). In addition, patients who developed PJI demonstrated higher thyroid-stimulating hormone levels than those without (P = .04). DiscussionSurgeons should be aware of this increased risk of PJI in hypothyroid patients when risk stratifying, and future studies are needed to determine the potential role of thyroxine supplementation.

A protocol for a systematic review of the diagnostic accuracy of blood markers, synovial fluid, and tissue testing in periprosthetic joint infections (PJI).

BackgroundTotal joint replacement (TJR) procedures have been one of the most rewarding interventions for treating patients suffering from joint disease. However, developing a periprosthetic joint infection (PJI) is a serious complication that is associated with the highest burden of cost and reduction in patients’ quality of life compared to other complications following TJRs. One of the main challenges facing clinicians who are treating PJIs is accurately diagnosing infection in a timely fashion. Multiple orthopedic associations have published clinical guidelines for diagnosing PJI which are based solely on consensus approaches, expert opinions, and narrative reviews. We believe that a higher quality of scientific rigor is necessary to establish a diagnostic guideline that represents current evidence more accurately and that identifies important knowledge gaps in PJI diagnosis. Therefore, we will conduct a systematic review on diagnostic performance of blood markers, synovial fluids, and tissue tests for diagnosing PJI.Methods/designElectronic search strategies will be developed and tested by an experienced medical information specialist in consultation with the review team, and gray literature will be searched using the checklist from CADTH’s Grey Matters Light. Two reviewers will independently screen the literature for inclusion using the prespecified eligibility criteria. Non-English language and animal-only studies will be excluded. Quality assessment and data extractions by reviewers will be verified, and disagreements will be resolved through consensus or third party adjudication. We will assess the quality of individual studies using the QUADAS-2 tool and use GRADE to summarize the strength of body of evidence. Analyses of evidence will be conducted in accordance with the Cochrane Handbook for Diagnostic Test Accuracy Reviews.DiscussionWe will conduct a systemic review of tests (blood markers, synovial fluids, and tissue testing) for diagnosing PJI in patients’ knee, hip, and shoulder joint replacements. This will be the first scientifically rigorous and comprehensive systematic review in the field and may feed into an evidence-based clinical practice guideline. We will compare the findings of this review with the consensus-based guides and discuss the differences, similarities, and knowledge gaps.Systematic review registrationPROSPERO CRD42015023768Electronic supplementary materialThe online version of this article (doi:10.1186/s13643-015-0124-1) contains supplementary material, which is available to authorized users.

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.

Low infection rate after tumor hip arthroplasty for metastatic bone disease in a cohort treated with extended antibiotic prophylaxis.

Background. Compared to conventional hip arthroplasty, endoprosthetic reconstruction after tumor resection is associated with a substantially increased risk of periprosthetic joint infection (PJI), with reported rates of around 10% in a recent systematic review. The optimal duration of antibiotic prophylaxis for this patient population remains unknown. Material and Methods. To establish the infection rate associated with prolonged antibiotic prophylaxis in our department, we performed a retrospective review of all adult patients who underwent endoprosthetic reconstruction of the proximal femur after tumor resection for metastatic bone disease during a 4-year period from 2010 to 2013 (n = 105 patients). Results. Intravenous antibiotic prophylaxis was administrated for an extended duration of a mean of 7.4 days. The overall infection rate was 3.6% (4/111 implants), infection free survival was 96% at 2 years, and the risk of amputation associated with infection was 25% (1/4 patients). Discussion. Preemptive eradication of bacterial contamination may be of value in certain clinical situations, where the risk level and consequences of implant-associated infection are unacceptable. Our findings suggest that extended postoperative antibiotic prophylaxis may reduce the risk of PJI in patients undergoing tumor resection and endoprosthetic replacement for metastatic bone disease associated impending or de facto pathologic fractures of the proximal femur.