Single,Recurrent, Synchronous,and Metachronous Periprosthetic Joint Infections in Patients With Multiple Hip and Knee Arthroplasties

BackgroundThe rate for periprosthetic joint infection (PJI) exceeds 1% for primary arthroplasties. Over 30% of patients who have a primary arthroplasty require an additional arthroplasty, and the impact of PJI on this population is understudied. Our objective was to assess the prevalence of recurrent, synchronous, and metachronous PJI in patients who had multiple arthroplasties and to identify risk factors for a subsequent PJI.MethodsWe identified 337 patients who had multiple arthroplasties and at least 1 PJI that presented between 2003 and 2021. The mean follow-up after revision arthroplasty was 3 years (range, 0 to 17.2). Patients who had multiple infected prostheses were categorized as synchronous (ie, presenting at the same time as the initial infection) or metachronous (ie, presenting at a different time as the initial infection). The PJI diagnosis was made using the MusculoSkeletal Infection Society (MSIS) criteria.ResultsThere were 39 (12%) patients who experienced recurrent PJI in the same joint, while 31 (9%) patients developed PJI in another joint. Positive blood cultures were more likely in the second joint PJI (48%) compared to recurrent PJI (23%) or a single PJI (15%, P < .001). Synchronous PJI represented 42% of the second joint PJI cases (n = 13), while metachronous PJI represented 58% (n = 18). Tobacco users had 75% higher odds of metachronous PJI (odds ratio 1.75, 95% confidence interval: 1.1-2.9, P = .041).ConclusionOver 20% of the patients with multiple arthroplasties and a single PJI will develop a subsequent PJI in another arthroplasty with 12% recurring in the initial arthroplasty and nearly 10% ocurring in another arthroplasty. Particular caution should be taken in patients who use tobacco, have bacteremia, or have Staphylococcus aureus isolation at time of their initial PJI. Optimizing the management of this high-risk patient population is necessary to reduce the additional burden of subsequent PJI.Level of EvidencePrognostic Level IV.     

Risk Factors for Failure and Optimal Treatment of Total Joint Arthroplasty for Septic Arthritis

BackgroundPatients with native joint septic arthritis are one of the highest risk groups for developing complications following total joint arthroplasty (TJA), especially periprosthetic joint infection(PJI). There is a paucity of information on the risk factors for developing PJI and the optimal treatment modality of the native septic joint that can mitigate that risk. This multicenter study aimed to determine these risk factors, including prior treatment.MethodsA retrospective study of 233 TJAs performed, following prior septic arthritis at five institutions, was conducted. Comorbidities, organism profile, prior surgery, etiology of septic arthritis, and other relevant variables were reviewed. The primary outcome was the development of PJI, defined by Musculoskeletal Infection Society criteria. Bivariate and multivariate analyses were performed to identify risk factors for PJI.ResultsOverall, the PJI rate was 12.4% in patients who underwent TJA after native septic arthritis. Predisposing risk factors for PJI included antibiotic-resistant organisms, male gender, diabetes, and a postsurgical cause of septic arthritis eg open reduction internal fixation. When controlling for potential confounders, multivariate analysis revealed that male gender, diabetes, and a postoperative etiology were predictors of PJI. The definitive treatment modality for the septic joint did not affect the rate of PJI for both arthroscopy vs irrigation and debridement (I&D), and two-stage exchange vs single-stage procedure.DiscussionThis study has identified several risk factors for developing PJI in patients with prior septic joint arthritis, some of which are modifiable. The initial treatment modality of the native septic joint has no bearing on the development of PJI after TJA.     

Risk of Periprosthetic Joint Infection After Intra-Articular Corticosteroid Injection Following Unicompartmental Knee Arthroplasty

BackgroundPerioperative intra-articular joint injection is a known risk factor for developing prosthetic joint infection (PJI) in the immediate preoperative and postoperative periods for total knee arthroplasty, but is less defined in unicompartmental knee arthroplasty (UKA). The goal of this study was to elucidate the risk of developing PJI after intra-articular corticosteroid injection (IACI) into a post UKA knee.MethodsA retrospective review of a nationwide administrative claims database was performed from January 2015 to October 2020. Patients who underwent UKA and had an ipsilateral IACI were identified and matched 2:1 to a control group of primary UKA patients who did not receive IACI. Multivariate logistic analyses were conducted to assess differences in PJI rates at 6 months, 1 year, and 2 years.ResultsA total of 47,903 cases were identified, of which 2,656 (5.5%) cases received IACI. The mean time from UKA to IACI was 355 days. The incidence of PJI in the IACI group was 2.7%, compared to 1.3% in the control group. The rate of PJI after IACI was significantly higher than the rate in the control group at 6 months, 1 year, and 2 years (all P < .05). The majority of PJI occurred within the first 6 months following IACI (75%).ConclusionIn this study, IACI in a UKA doubled the risk of PJI compared to patients who did not receive an injection. Surgeons should be aware of this increased risk to aid in their decision-making about injecting into a UKA.Level of EvidenceIII, retrospective comparative study.     

Risk of Periprosthetic Joint Infection in Patients With Multiple Arthroplasties

Background

Risk 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.

Risk of Periprosthetic Joint Infection in Patients With Total Knee Arthroplasty Undergoing Colonoscopy: A Nationwide Propensity Score Matched Study

BackgroundThe post-colonoscopy periprosthetic joint infection (PJI) risk in patients with total prosthetic knee joints has limited research. The present study investigated the PJI risk and determined the risk factors for post-colonoscopy PJI in total knee arthroplasty (TKA) recipients. The hypothesis was that colonoscopy is associated with an increased PJI risk in patients with total prosthetic knee joints. This study can potentially help guide the decision making for prophylactic antibiotic use for colonoscopy.MethodsThis nationwide matched cohort study used claims data from the Health Insurance Review and Assessment Service database and enrolled patients who underwent unilateral TKA between 2008 and 2016. The history of diagnostic colonoscopy was investigated at least 1 year postoperatively. The propensity score was matched between colonoscopy and non-colonoscopy cohorts, and the post-colonoscopy PJI risk was compared. The PJI risk following invasive colonoscopic procedures, including biopsy, polypectomy, and mucosal or submucosal resection, was investigated, and the risk factors for post-colonoscopy PJI were determined.ResultsIn total, 45,612 and 211,841 patients were matched in the colonoscopy and control cohorts, respectively. The colonoscopy cohort had greater 9-month and 1-year PJI risks from the index colonoscopy date than the matched controls (9 months: hazard ratio [HR] 1.836, P = .006; 1 year: HR 1.822, P = .031). Invasive colonoscopic procedures did not increase the PJI risk at any time point post-colonoscopy. The only significant risk factor for PJI was post-traumatic arthritis (adjusted HR 4.034, P = .023).ConclusionColonoscopy was associated with an increased PJI risk in TKA recipients, regardless of concomitant invasive colonoscopic procedures.Level of evidenceIII, Prognostic.     

Successive new-pathogen prosthetic joint reinfections: Observational cohort study on 61 patients

ObjectivesProsthetic joint infection (PJI) treatment failure may be due to relapsing infection (same microorganism) or new-pathogen reinfection (npPJI). The aim was to describe npPJI epidemiological, clinical and microbiological characteristics, their treatments and outcomes, and identify their risk factors.MethodsThis observational, single-center, cohort study was conducted in a French Referral Center for Bone-and-Joint Infections between September 2004 and December 2015. Patients treated for at least two successive hip or knee PJIs in the same joint with a different pathogen were identified in the prospective database. We compared each patient's first PJI and subsequent npPJI(s) to analyze the type and microbiological characteristics of npPJIs. To search for npPJI risk factors, we compared those cases to a random selection of 122 “unique-episode” PJIs treated during the study period.ResultsAmong 990 PJIs, 79 (8%) npPJIs occurring in 61 patients were included. New-pathogen prosthetic joint infections (npPJIs) developed more frequently in knee (14%) than hip prostheses (5%). Median interval from the first PJI to the npPJI was 26 months. New-pathogen prosthetic joint reinfections (npPJIs) more frequently spread hematogenously (60% vs 33%) and were predominantly caused by Staphylococcus (36%) or Streptococcus (33%) species. Multivariate analysis identified two risk factors: chronic dermatitis (odds ratio: 6.23; P < 0.05) and cardiovascular diseases (odds ratio: 2.71; P < 0.01). A curative strategy was applied to 70%: DAIR (29%), one-stage (28%), two-stage exchange arthroplasty (7%) or other strategies (7%). The others received prolonged suppressive antibiotic therapy (30%).ConclusionsNew-pathogen prosthetic joint infections (npPJIs) are complex infections requiring management by multidisciplinary teams that should be adapted to each clinical situation.     

2-stage revision recommended for treatment of fungal hip and knee prosthetic joint infections

Background and purpose Fungal prosthetic joint infections are rare and difficult to treat. This systematic review was conducted to determine outcome and to give treatment recommendations.

Patients and methods After an extensive search of the literature, 164 patients treated for fungal hip or knee prosthetic joint infection (PJI) were reviewed. This included 8 patients from our own institutions.

Results Most patients presented with pain (78%) and swelling (65%). In 68% of the patients, 1 or more risk factors for fungal PJI were found. In 51% of the patients, radiographs showed signs of loosening of the arthroplasty. Candida species were cultured from most patients (88%). In 21% of all patients, fungal culture results were first considered to be contamination. There was co-infection with bacteria in 33% of the patients. For outcome analysis, 119 patients had an adequate follow-up of at least 2 years. Staged revision was the treatment performed most often, with the highest success rate (85%).

Interpretation Fungal PJI resembles chronic bacterial PJI. For diagnosis, multiple samples and prolonged culturing are essential. Fungal species should be considered to be pathogens. Co-infection with bacteria should be treated with additional antibacterial agents.

We found no evidence that 1-stage revision, debridement, antibiotics, irrigation, and retention (DAIR) or antifungal therapy without surgical treatment adequately controls fungal PJI. Thus, staged revision should be the standard treatment for fungal PJI. After resection of the prosthesis, we recommend systemic antifungal treatment for at least 6 weeks—and until there are no clinical signs of infection and blood infection markers have normalized. Then reimplantation can be performed.     

A History of Treated Periprosthetic Joint Infection Increases the Risk of Subsequent Different Site Infection

Background

After the successful treatment of periprosthetic joint infection (PJI), patients may present with degenerative joint disease in another joint with symptoms severe enough to warrant arthroplasty. However, it is not known whether patients with a history of treated PJI at one site will have an increased risk of PJI in the second arthroplasty site.

Questions/purposes

The primary objective of this study is to determine if there is a difference in the risk of developing a PJI after a second total hip arthroplasty (THA) or total knee arthroplasty (TKA) in patients who have had a previous PJI at another anatomic site compared with patients who have had no history of PJI. The secondary objective is to determine other potential risk factors that may predict PJI at the site of the second arthroplasty.

Methods

A retrospective matched cohort study was performed to identify all patients at four academic institutions successfully treated for PJI who subsequently underwent a second primary THA or TKA (n = 90), constituting our study group. Patients were matched (one-to-one) to control subjects who had no history of PJI after their first arthroplasty (n = 90); they were matched based on age, sex, diabetic status, BMI, American Society of Anesthesiologists, institution, joint of interest, and year of surgery (± 2 years). We compared the case and control groups to determine whether a prior infection increased the relative risk of a subsequent PJI at another anatomic site. To identify other potential risk factors for subsequent PJI, a subgroup univariate analysis of our study group (n = 90) was performed. To identify other potential risk factors for subsequent PJI, a subgroup univariate analysis of our study group (n = 90) was performed.

Results

Patients with a history of PJI had a greater risk of developing PJI in a subsequent THA or TKA (10 of 90 versus zero of 90 in the control group; relative risk, 21.00; 95% confidence interval [CI], 1.25–353.08; p = 0.035). Excluding PJI, we identified no other factors associated with a second joint infection. In patients with a history of PJI, a second PJI occurred more frequently in female patients (female: nine of 10 [90%] versus female: 40 of 80 [50%]; odds ratio [OR], 8.83; 95% CI, 1.13–403.33; p = 0.02) and in those whose initial infection was a staphylococcal species (subsequent PJI seven of 10 [70%] versus no subsequent PJI 28 of 80 [35%]; OR, 4.26; 95% CI, 0.89–27.50; p = 0.04).

Conclusions

A history of PJI predisposes patients to subsequent PJI in primary THA or THA. Patients and surgeons must be aware of the higher risk of this devastating complication before proceeding with a second arthroplasty.

Level of Evidence

Level III, prognostic study.     

Risk of methicillin-resistant staphylococcus aureus prosthetic joint infection in elective total hip and knee arthroplasty following eradication therapy

BACKGROUNDProsthetic joint infection (PJI) is a devastating complication requiring prolonged treatment and multiple operations, leading to significant morbidity for the patient. Patients are routinely tested for methicillin-resistant staphylococcus aureus (MRSA) colonisation. MRSA positive patients are given eradication therapy. We hypothesise that patients who are MRSA positive pre-operatively, have increased risk of developing PJI. AIMTo identify deep wound infection (PJI) rates in patients who are colonised MRSA positive compared with those who are not colonised; and long term clinical and radiological outcomes. METHODSAll patients who underwent total hip and knee replacements (THR/TKR) between December 2009 and December 2019 were identified. Patients who were also identified as being MRSA positive at pre-operative assessment were then selected. Confirmation of prescribing eradication treatment was recorded. Patient records, including consultation letters, operation notes and microbiology results were reviewed retrospectively. Comparison of outcomes for each MRSA positive patient was made with 2 MRSA negative patients undergoing the same operation of a similar age by the same consultant.RESULTSScreening identified 42 knee and 32 hip arthroplasty patients as MRSA positive, 84 MRSA negative knee and 64 hip patients were reviewed. Patients were matched with medical co-morbidities in each group. Mean follow up was 5 years. PJI was identified in 4/32 (12.5%) of THR MRSA positive and 3/42 (7%) of TKR patients. All patients had PJI within one year of surgery. CONCLUSIONMRSA positive patients are given eradication therapy routinely. However, no confirmation of eradication is sought. Patients who have MRSA colonisation pre-operatively, in our study had a significantly increased risk of PJI, when compared to negative patients. We would recommend establishing true eradication after treatment prior to arthroplasty.     

Effect of urinary tract infection on the risk of prosthetic joint infection: A systematic review and meta-analysis

PurposeUrinary tract infection (UTI) are very common in the general population, however it is unclear whether UTI is a risk factor of prosthetic joint infection (PJI). Our purposes were: (1) To determine whether UTI is a risk factor of PJI after joint replacement, and (2) to determine whether the microorganisms causing PJI and UTI are the same.MethodsPubMed, Web of Science, the Cochrane Library, and EMBASE were searched systematically for studies. The effect sizes of RR were calculated for included studies that reported raw counts with 95% CIs. The aim 1 of the study is a meta-analysis; the aim 2 is a systematic review.ResultsThe aim 1 indicated that the risk of PJI was significantly higher in the UTI group than in the control group (RR = 3.17; 95% CI, 2.19–4.59). The aim 2 indicated that the microorganisms of UTI and PJI were the same in the same patient, and these included Enterococcus faecalis, and Pseudomonas, which supports the theory of PJI occurring via the haematogenous route from the genitourinary tract that harbours bacteria in UTI.ConclusionThis study identified UTI as being significantly associated with PJI after joint arthroplasty and PJI occurring via the haematogenous route from the genitourinary tract harbouring bacteria in UTI. Therefore, postponing surgery and even treating patients with known UTI preoperatively are recommended.     

Performance of Sequencing Assays in Diagnosis of Prosthetic Joint Infection: A Systematic Review and Meta-Analysis

BackgroundA prompt, accurate diagnosis of prosthetic joint infection (PJI) allows early treatment, and with identification of the causative organism, sensitive antibiotics could be applied. However, routine methods cannot identify the causative organism under certain circumstances. Gene sequencing assays have unique superiority in promptness and broad coverage of pathogens, but evidence of its accuracy is quite limited.MethodsOf 247 citations identified for screening, 12 studies with 1965 patients in total were included. The diagnostic value of sequencing assays in PJI was systematically reviewed. Subgroup analysis was conducted to explore the source of heterogeneity.ResultsPooled sensitivity was 0.81 (95% confidence interval [CI], 0.73-0.87); pooled specificity was 0.94 (95% CI, 0.91-0.97); positive likelihood ratio was 14.2 (95% CI, 8.7-23.4); negative likelihood ratio was 0.20 (95% CI, 0.14-0.29); and the area under the curve was 0.94 (95% CI, 0.18-1.00). The results of subgroup analysis revealed that antibiotics reduced the sensitivity of sequencing-based diagnosis compared with withholding antibiotics before sampling (0.71 vs 0.94). In another subgroup analysis, sequencing by synthesis (Illumina sequencing) had better specificity than other next-generation sequencing methods (0.963 vs 0.829) and specificity similar to time-consuming and laborious Sanger sequencing (0.963 vs 0.967).ConclusionSequencing assays had favorable diagnostic accuracy of PJI. When sequencing assays were applied to diagnosing PJI, an antibiotic-free interval before sampling may enhance the ability to detect the causative organism and, among next-generation sequencing methods, sequencing by synthesis seemed to have advantages over other methods in specificity.     

Preoperative waiting time increased the risk of periprosthetic infection in patients with femoral neck fracture

Background and purpose Prosthetic joint infection (PJI) remains a devastating complication of arthroplasty. Today, most displaced femoral neck fractures in the elderly are treated with arthroplasty. We estimated the incidence of and risk factors for PJI in primary arthroplasty after femoral neck fracture.

Patients and methods Patients admitted for a femoral neck fracture in 2008 and 2009 were registered prospectively. We studied clinical, operative, and infection data in 184 consecutive patients.

Results 9% of the patients developed a PJI. Coagulase-negative staphylococci and Staphylococcus aureus were the most frequently isolated organisms. We found that preoperative waiting time was associated with PJI and also with urinary tract infection. The median preoperative waiting time was 37 (11–136) h in the infection group as opposed to 26 (4–133) h in the group with no infection (p = 0.04). The difference remained statistically significant after adjusted analysis. The success of treatment with debridement and retention of the prosthesis was limited, and 5 of the 17 patients with PJI ended up with a resection arthroplasty. The 1-year mortality rate was 21% in the patients with no infection, and it was 47% in the infection group (p = 0.03).

Interpretation We found a high incidence of PJI in this elderly population treated with arthroplasty after hip fracture, with possibly devastating outcome. The length of stay preoperatively increased the risk of developing PJI.     

Second-site prosthetic joint infection in patients with multiple prosthetic joints

Introduction

Prosthetic joint infections (PJIs) are among the most serious complications in arthroplasty. A second-site PJI in patients with multiple prosthetic joints increases morbidity, with many requiring further revision procedures. We aimed to establish why some patients with multiple joints develop second-site infections.

Methods

Our institution’s arthroplasty database was reviewed from 2004 to 2017. All PJIs were identified, and all patients with more than one prosthetic joint in situ were included. We recorded risk factors, causative organisms, number of procedures and length of stay.

Results

Forty-four patients meeting the criteria were identified. Four patients (9.1%) developed second-site infection. Eight patients (18.2%) developed re-infection of the primary PJI. Positive MRSA carrier status and PJI of a total knee replacement were associated with an increased risk of a second episode of infection. Patients who developed further infection had more frequent admission and longer lengths of stay than isolated PJIs.

Discussion

Higher morbidity and use of hospital resources are associated with this cohort of patients. PJIs in total knee replacements and positive MRSA status are associated with higher rates of second infection. Identifying this vulnerable cohort of patients at an early stage is critical to ensure measures are taken to reduce the risks of further infection.

     

Is Patient-reported Penicillin Allergy Independently Associated with Increased Risk of Prosthetic Joint Infection After Total Joint Arthroplasty of the Hip,Knee, and Shoulder?

BackgroundPatients with a patient-reported penicillin allergy may be at greater risk for postoperative prosthetic joint infection (PJI) after total joint arthroplasty of the hip, knee, or shoulder. The increased risk of PJI in these patients has been attributed to these patients receiving a less-effective perioperative antibiotic. However, prior reports did not fully address the clinical characteristics of these unique patients, who may inherently be at greater risk of having a PJI, which may confound prior findings.Questions/purposesAfter controlling for risk factors for PJI such as BMI, anxiety, depression, and other comorbidities, we asked: Are patients with a patient-reported penicillin allergy more likely to have a PJI after THA, TKA, or total shoulder arthroplasty than patients without such a reported allergy?MethodsWe queried patient records from 2010 to 2017 from a nationwide administrative claims database of 122 million patients to adequately power an investigation comparing the 1-year incidence of PJI after TKA, total shoulder arthroplasty, and THA in patients with patient-reported penicillin allergy versus patients without a patient-reported penicillin allergy. Operative treatments for deep joint infection, identified by Current Procedural Terminology and ICD-9 and ICD-10 codes were used as a surrogate for PJI. Clinical characteristics such as age, sex, BMI, length of stay, and Charlson comorbidity index and specific comorbidities including alcohol abuse, anemia, anxiety, cardiac disease, diabetes, immunocompromised status, rheumatoid arthritis, depression, liver disease, chronic kidney disease, tobacco use, and peripheral vascular disease were queried for each study group. The odds of PJI within 1 year of THA, TKA, or total shoulder arthroplasty were compared using multiple logistic regression after adjusting for potential confounders.ResultsAfter adjusting for potential confounding factors such as BMI, anxiety, depression and other comorbidities, we found that patient-reported penicillin allergy was independently associated with an increased odds of PJI after TKA (odds ratio 1.3 [95% confidence interval 1.1 to 1.4]; p < 0.01) and total shoulder arthroplasty (OR 3.9 [95% CI 2.7 to 5.4]; p < 0.01). However, patient-reported penicillin allergy was not independently associated with an increased odds of PJI after THA (OR 1.1 [95% CI 0.9 to 1.3]; p = 0.36) after controlling for the same risk factors.ConclusionsIn this study, we found that patients with patient-reported penicillin allergy were at an increased risk for PJI after TKA and total shoulder arthroplasty, which we suspect—but cannot prove—is likely a function of those patients receiving a second-line antibiotic for presurgical prophylaxis. Since prior research has found that many patients listed in medical records as having a penicillin allergy are in fact not allergic to penicillin, we suggest that surgeons consider preoperative allergy testing, such as using an intraoperative test dose, to aid in choosing the most appropriate antibiotic choice before knee or shoulder arthroplasty and to amend patient medical records based on testing results. Future studies should determine whether this additional diagnostic maneuver is cost-effective.Level of EvidenceLevel III, therapeutic study.     

The Cost-Effectiveness of Extended Oral Antibiotic Prophylaxis for Infection Prevention After Total Joint Arthroplasty in High-Risk Patients

BackgroundExtended oral antibiotic prophylaxis may decrease rates of prosthetic joint infection (PJI) after total joint arthroplasty (TJA) in patients at high risk for infection. However, the cost-effectiveness of this practice is not clear. In this study, we used a break-even economic model to determine the cost-effectiveness of routine extended oral antibiotic prophylaxis for PJI prevention in high-risk TJA patients.MethodsBaseline PJI rates in high-risk patients, the cost of revision arthroplasty for PJI, and the costs of extended oral antibiotic prophylaxis regimens were obtained from the literature and institutional purchasing records. These variables were incorporated in a break-even economic model to calculate the absolute risk reduction (ARR) in infection rate necessary for extended oral antibiotic prophylaxis to be cost-effective. ARR was used to determine the number needed to treat (NNT).ResultsExtended oral antibiotic prophylaxis with Cefadroxil in patients at high risk for PJI was cost-effective at an ARR in baseline infection rate of 0.187% (NNT = 535) and 0.151% (NNT = 662) for TKA and THA, respectively. Cost-effectiveness was preserved with varying costs of antibiotic regimens, PJI treatment costs, and infection rates.ConclusionThe use of extended oral antibiotic prophylaxis may reduce PJI rates in patients at high risk for infection following TJA and appears to be cost-effective. However, the current evidence supporting this practice is limited in quality. The use of extended oral antibiotic prophylaxis should be weighed against the possible development of future antimicrobial resistance, which may change the value proposition.     

Are Patient-Reported Drug Allergies Associated With Prosthetic Joint Infections and Functional Outcomes Following Total Hip and Knee Arthroplasty?

BackgroundThe purpose of this study is to determine if the number and types of patient-reported drug allergies are associated with prosthetic joint infection (PJI) and functional outcomes following total joint arthroplasty (TJA).MethodsThis is a retrospective review of all patients who underwent a primary, elective total hip (THA) or knee arthroplasty (TKA) over a 10-year period at a single academic institution. Demographic, clinical information, and number and type of patient-reported drug allergy was collected. Univariate and multivariate logistic regressions were performed to identify risk factors for PJI and risk of PJI based on number of allergies. Univariate analysis was also performed to identify if the number of patient-reported allergies affected functional outcome scores.ResultsOf 31,109 patients analyzed, there were 941 (3%) revisions for infection (491 knees and 450 hips). At least one allergy was reported by 16,435 (52.8%) patients, with a mean of 1.2 ± 1.9. Those who underwent revision for infection had a significantly higher number of reported allergies (1.68 ± 1.9 vs 1.23 ± 1.9, P < .0005, 95% confidence interval ?0.58 to 0.33). On univariate regression the number of allergies independently predicted revision TJA for infection (P < .0001) as did age, gender, body mass index, and smoking status. On multivariate regression for each additional patient-reported allergy, risk of PJI increased by 1.11 times (95% confidence interval 1.07-1.14, P < .0001). Number of patient-reported allergies did not predict 3-month or 1-year functional outcome scores.ConclusionPatients with a higher number of reported allergies may be at increased risk of PJI following TJA.Level of EvidencePrognostic Level II.     

A Missed Opportunity: The Impact of Hepatitis C Treatment Prior to Total Knee Arthroplasty on Postoperative Complications

BackgroundHepatitis C (HCV) is undertreated and increasing in prevalence. Its influence on outcomes following total knee arthroplasty (TKA) remains unclear. The purpose of this study is to examine the impact of HCV and prearthroplasty antiviral treatment on postoperative complications following TKA.MethodsA retrospective matched cohort study was conducted using an administrative claims database to compare postoperative complication rates following TKA for (1) patients with vs without HCV and (2) among patients with HCV, patients with antiviral treatment before TKA vs no treatment. In total, 6971 patients with HCV were matched 1:4 with 27,884 controls without HCV, and 708 HCV patients with antiviral treatment before TKA were matched 1:2 with 1416 HCV patients without treatment. Rates of joint complications at 1 and 2 years postoperatively were compared via multivariable logistic regression.ResultsThe HCV cohort exhibited significantly higher risk of prosthetic joint infection (PJI) than controls at both 1 (4.1 vs 2.1%; odds ratio [OR] 1.58) and 2 years (5.0% vs 2.7%; OR 1.55) postoperatively. Rates of revision TKA were also significantly higher for HCV patients at 1 (2.8% vs 1.8%; OR 1.40) and 2 years (4.1% vs 2.9%; OR 1.30). HCV patients with prearthroplasty antiviral treatment exhibited significantly lower risk of PJI at 1 (2.1% vs 4.1%; OR 0.50) and 2 years (2.7% vs 5.1%, OR 0.51) compared to patients without treatment.ConclusionPatients with HCV have significantly increased risk of PJI and revision arthroplasty following TKA. Antiviral treatment before TKA significantly decreases the risk of PJI postoperatively.Level of EvidenceLevel III.     

Proton-pump inhibitors are associated with increased risk of prosthetic joint infection in patients with total hip arthroplasty: a case-cohort study

Background and purpose — Proton-pump inhibitors (PPI) have previously been associated with an increased risk of infections such as community-acquired pneumonia, gastrointestinal infections and central nervous system infection. Therefore, we evaluated a possible association between proton-pump inhibitor use and prosthetic joint infection (PJI) in patients with total hip arthroplasty (THA), because they can be stopped perioperatively or switched to a less harmful alternative.Patients and methods — A cohort of 5,512 primary THAs provided the base for a case-cohort design; cases were identified as patients with early-onset PJI. A weighted Cox proportional hazard regression model was used for the study design and to adjust for potential confounders.Results — There were 75 patients diagnosed with PJI of whom 32 (43%) used PPIs perioperatively compared with 75 PPI users (25%) in the control group of 302 patients. The risk of PJI was 2.4 times higher (95% CI 1.4–4.0) for patients using PPI. This effect remained after correction for possible confounders.Interpretation — The use of PPIs was associated with an increased risk of developing PJI after THA. Hence, the use of a PPI appears to be a modifiable risk factor for PJI.

One important aspect of the prevention of prosthetic joint infection (PJI) is preoperative optimization of modifiable risk factors (Kunutsor et al. 2016). Medication may be an important category of modifiable risk factors, since they can be temporarily discontinued perioperatively or they can be switched to a less harmful alternative. Proton-pump inhibitors (PPI) are of special interest, because they have been associated with an increased risk of infections such as community-acquired pneumonia, gastrointestinal infections, and central nervous system infections (Lambert et al. 2015, Cunningham et al. 2018, Hung et al. 2018). The increased risk of these infections is probably due to the fact that PPIs decrease the effectiveness of neutrophils (Aybay et al. 1995, Agastya et al. 2000, Zedtwitz-Liebenstein et al. 2002). This increased risk of infection may also apply to total hip arthroplasty (THA), possibly leading to increased risk of PJI. However, the effect of PPIs on the risk of PJI is currently unknown. Therefore, we evaluated a possible association between perioperative PPI use and early-onset prosthetic joint infection in patients with total hip arthroplasty.