Low-Dose Aspirin Administered for Venous Thromboembolism Prophylaxis Reduces the Incidence of Heterotopic Ossification in Total Joint Arthroplasty

BackgroundHeterotopic ossification (HO) is a common complication following total joint arthroplasty (TJA). However, the pathophysiology of HO is not entirely understood. Inflammation may play a significant role in the pathogenesis of HO as nonsteroidal anti-inflammatory drugs are effective in the prevention of HO. The purpose of this study is to examine if aspirin (ASA), when used as venous thromboembolism (VTE) prophylaxis, influenced the rate of HO formation following TJA.MethodsWe queried our longitudinally maintained database to identify all patients who underwent primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) for osteoarthritis between January 2016 and June 2018 with at least 3-month radiographic follow-up. In total, 1238 THAs and 1051 TKAs were included for analysis. Radiographs were reviewed and HO formation graded according to the Brooker classification. Patient demographic and VTE prophylaxis data were collected and reviewed for accuracy. Univariate and multivariate analysis was performed to evaluate the effect of ASA on HO formation.ResultsThe overall rate of HO was 37.5% after THA and 17.4% after TKA. Patients receiving ASA were less likely to develop HO after THA (34.8% vs 45.5%; P < .001), as well as HO after TKA (13.4% vs 18.4%; P = .047) compared to patients receiving non-ASA VTE prophylaxis. The rate of HO formation trended to be lower, albeit not statistically significantly, in patients receiving low-dose ASA (81 mg) vs high-dose ASA (325 mg).ConclusionPatients undergoing primary TJA receiving ASA for VTE prophylaxis were less likely to develop HO compared to patients who were administered non-ASA VTE prophylaxis.     

Visceral Fat as a Risk Factor for Periprosthetic Joint Infection After Total Hip and Knee Arthroplasty

BackgroundVisceral obesity, a strong indicator of chronic inflammation and impaired metabolic health, has been shown to be associated with poor postoperative outcomes and complications. This study aimed to evaluate the relationship between visceral fat area (VFA) and periprosthetic joint infection (PJI) in total joint arthroplasty (TJA) patients.MethodsA retrospective study of 484 patients who had undergone a total hip or knee arthroplasty was performed. All patients had a computed tomography scan of the abdomen/pelvis within two years of their TJA. Body composition data (ie, VFA, subcutaneous fat area, and skeletal muscle area) were calculated at the Lumbar-3 vertebral level via two fully automated and externally validated machine learning algorithms. A multivariable logistic model was created to determine the relationship between VFA and PJI, while accounting for other PJI risk factors. Of the 484 patients, 31 (6.4%) had a PJI complication.ResultsThe rate of PJI among patients with VFA in the top quartile (> 264.1 cm²) versus bottom quartile (< 82.6 cm²) was 5.6% versus 10.6% and 18.8% versus 2.7% in the total hip arthroplasty and total knee arthroplasty cohorts, respectively. In the multivariate model, total knee arthroplasty patients with a VFA in the top quartile had a 30.5 times greater risk of PJI than those in the bottom quartile of VFA (P = .0154).ConclusionVFA may have a strong association with PJI in TJA patients. Using a standardized imaging modality like computed tomography scans to calculate VFA can be a valuable tool for surgeons when assessing risk of PJI.     

Persistent Wound Drainage among Total Joint Arthroplasty Patients Receiving Aspirin vs Coumadin

BackgroundPersistent wound drainage (PWD) is one of the major risk factors for periprosthetic joint infections (PJI), arguably the most dreaded complications after a total hip and knee arthroplasty (THA and TKA). The aim of this study is to identify the rates of PWD among THA and TKA patients who received aspirin (ASA) or Coumadin for postoperative venous thromboembolism (VTE) prophylaxis.MethodsRetrospective review of 5516 primary THA and TKA was performed. Patients with PWD were identified. Chi-square test was used to compare the incidences of PWD, 30-day VTE, and PJI at 6 months between the ASA and Coumadin groups. Multivariate regression model was used to identify independent risk factors for PWD using Charlson and Elixhauser comorbidity indexes.ResultsThe prevalence of PWD was 6.4% (353/5516). Patients receiving ASA had lower incidence of PWD (3.2% vs 8.5%, P < .0001) while having comparable rates of 30-day VTE (1.3% vs 1.4%, P = .722) and PJI at 6 months (1.8% vs 1.4%, P = .233) compared to those receiving Coumadin. Risk factors for PWD were diabetes (odds ratio [OR], 19.3; 95% confidence interval [CI], 11.8-23.2), rheumatoid arthritis (OR, 15.3; 95% CI, 10.8-17.2), morbid obesity (OR, 13.2; 95% CI, 9.7-17.5), chronic alcohol use (OR, 3.5; 95% CI, 1.8-5.5), hypothyroidism (OR, 1.9; 95% CI, 1.1-3.2), and Coumadin (OR, 1.7; 95% CI, 1.2-2.2).ConclusionUse of ASA is associated with significantly lower rates of PWD after THA and TKA when compared to Coumadin while being equally efficacious at preventing VTE. Coumadin was found to be an independent risk factor for PWD.     

No Difference in the Rate of Periprosthetic Joint Infection in Patients Undergoing the Posterolateral Compared to the Direct Anterior Approach

BackgroundThere remains inconsistent data about the association of surgical approach and periprosthetic joint infection (PJI). We sought to evaluate the risk of reoperation for superficial infection and PJI after primary total hip arthroplasty (THA) in a multivariate model.MethodsWe reviewed 16,500 primary THAs, collecting data on surgical approach and all reoperations within 1 year for superficial infection (n = 36) or PJI (n = 70). Considering superficial infection and PJI separately, we used Kaplan–Meier survivorship to assess survival free from reoperation and a Cox Proportional Hazards multivariate models to assess risk factors for reoperation.ResultsBetween direct anterior approach (DAA) (N = 3,351) and PLA (N = 13,149) cohorts, rates of superficial infection (0.4 versus 0.2%) and PJI (0.3 versus 0.5%) were low and survivorship free from reoperation for superficial infection (99.6 versus 99.8%) and PJI (99.4 versus 99.7%) were excellent at both 1 and 2 years. The risk of developing superficial infection increased with high body mass index (BMI) (hazard ratio [HR] = 1.1 per unit increase, P = .003), DAA (HR = 2.7, P = .01), and smoking status (HR = 2.9, P = .03). The risk of developing PJI increased with the high BMI (HR = 1.04, P = .03), but not surgical approach (HR = 0.68, P = .3).ConclusionIn this study of 16,500 primary THAs, DAA was independently associated with an elevated risk of superficial infection reoperation compared to the PLA, but there was no association between surgical approach and PJI. An elevated patient BMI was the strongest risk factor for superficial infection and PJI in our cohort.Level of EvidenceIII, retrospective cohort study.     

Hypoalbuminemia Predicts Failure of Two-Stage Exchange for Chronic Periprosthetic Joint Infection of the Hip and Knee

BackgroundNutritionally compromized patients, with preoperative serum albumin (SAB) < 3.5g/dL, are at higher risk for periprosthetic joint infection (PJI) in total joint arthroplasty. The relationship between nutritional and PJI treatment success is unknown. The purpose of this study was to examine the relationship between preresection nutrition and success after first-stage resection in planned two-stage exchange for PJI.MethodsA retrospective review was performed on 418 patients who had first-stage resection of a planned two-stage exchange for chronic hip or knee PJI between 2014 and 2018. A total of 157 patients (58 hips and 99 knees) were included who completed first stage, had available preop SAB and had a 2-year follow-up. Failure was defined as persistent infection or repeat surgery for infection after resection. Demographic and surgical data were abstracted and analyzed.ResultsAmong knee patients with preop SAB >3.5 g/dL, the failure rate was 32% (15 of 47) versus a 48% (25 of 40) failure rate when SAB <3.5 g/dL (P = .10). Similarly, the failure rate among hip patients with preop SAB >3.5 g/dL versus 12.5% (3 of 24) versus 44% (15 of 34) for hip patients with SAB <3.5 g/dL (P = .01). Multivariable regression results indicated that patients with SAB< 3.5 g/dL (P = .0143) and Musculoskeletal Infection Society host type C (P = .0316) were at an increased risk of failure.ConclusionLow preoperative SAB and Musculoskeletal Infection Societyhost type-C are independent risk factors for failure following first-stage resection in planned two-stage exchange for PJI. Efforts to nutritionally optimize PJI patients, when possible, may improve the outcome of two-stage exchange.     

Low-Dose vs Regular-Dose Aspirin for Venous Thromboembolism Prophylaxis in Primary Total Joint Arthroplasty

BackgroundConsensus on whether low-dose (81 mg) or regular-dose (325 mg) aspirin (ASA) is more effective for venous thromboembolism (VTE) chemoprophylaxis in primary total joint arthroplasties (TJAs) is not reached. The goal of this study is to evaluate the efficacy of low-dose and regular-dose ASA for VTE chemoprophylaxis in primary total hip arthroplasties and total knee arthroplasties.MethodsWe retrospectively identified 3512 primary TJAs (2344 total hip arthroplasties and 1168 total knee arthroplasties) with ASA used as VTE chemoprophylaxis between 2000 and 2019. Patients received ASA twice daily for 4-6 weeks after surgery with 961 (27%) receiving low-dose ASA and 2551 (73%) receiving regular-dose ASA. The primary endpoint was 90-day incidence of symptomatic VTEs. Secondary outcomes were gastrointestinal (GI) bleeding events and mortality. The mean age at index TJA was 66 years, 54% were female, and mean body mass index was 31 kg/m². The mean Charlson Comorbidity Index was 3.5. Mean follow-up was 3 years.ResultsThere was no difference in 90-day incidence of symptomatic VTEs between low-dose and regular-dose ASA (0% vs 0.1%, respectively; P = .79). There were no GI bleeding events in either group. There was no difference in 90-day mortality between low-dose and regular-dose ASA (0.3% vs 0.1%, respectively; P = .24).ConclusionIn 3512 primary TJA patients treated with ASA, we found a cumulative incidence of VTE <1% at 90 days. Although this study is underpowered, it appears that twice daily low-dose ASA was equally effective to twice daily regular-dose ASA for VTE chemoprophylaxis, with no difference in risk of GI bleeds or mortality.Level of EvidenceIII, retrospective cohort study.     

Is Dual Antibiotic-Loaded Bone Cement More Effective and Cost-Efficient Than a Single Antibiotic-Loaded Bone Cement to Reduce the Risk of Prosthetic Joint Infection in Aseptic Revision Knee Arthroplasty?

BackgroundHigher rates of prosthetic joint infections (PJIs) are related to patient risk factors and/or to special surgical procedures such as revision total knee arthroplasty (rTKA). Among the measures discussed to better protect those patients from the higher infection risks use of dual antibiotic-loaded bone cement has emerged as a further prophylactic option.MethodsThis retrospective study included 246 patients undergoing strictly aseptic revision knee arthroplasty at our institution in the time period 2015-2018. Based on the type of bone cement used for the cementation of the revision prosthesis, 2 groups were defined. In total, 143 patients received the low-dose single antibiotic-loaded bone cement (SALBC) PALACOS R+G and 103 patients received the high-dose dual antibiotic-loaded bone cement (DALBC) COPAL G+C. The number of PJI cases in each group over a follow-up time of minimum 1 year was compared and the extra costs for the DALBC use calculated against the economic savings per each avoided PJI case on basis of 3 different assumptions (treatment costs and amount of cement use).ResultsUse of DALBC in aseptic rTKA was associated with a significant reduction in PJI cases (relative risk = 57%, PJI rate in the SALBC group 4.1% vs 0% in the DALBC group, P = 0.035). The calculated total savings per patient was $1367. Depending on the economic assumptions the range of savings was between $1413 (less favorable calculation model) and $3661 (most favorable calculation model).ConclusionThe use of DALBC in rTKA has been found to be more effective in preventing PJI and proved cost-efficient in all our cost-calculation models.     

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.     

Socioeconomic Status May Not Be a Risk Factor for Periprosthetic Joint Infection

BackgroundPeriprosthetic joint infection (PJI) is a devastating complication after total joint arthroplasty, carrying significant economic and personal burden. The goal of this study is to use an established database to analyze socioeconomic variables and assess their relationship to PJI. Additionally, we sought to evaluate whether socioeconomic factors, along with other known risk factors of PJI, when controlled for in a statistical model affected the familial risk of PJI.MethodsWith approval from our Institutional Review Board we performed a population-based retrospective cohort study on all primary total joint arthroplasty cases of the hip or knee (n = 85,332), within a statewide database, between January 1996 and December 2013. We excluded 9854 patients due to age <18 years, missing data, history of PJI prior to index procedure, and no evidence of 2-year follow-up (excluding those with PJI). Cases that developed PJI following the index procedure (n = 2282) were compared to those that did not (n = 73,196).ResultsAfter adjusting for covariates, patients with Medicaid as a primary payer were at greater risk for experiencing PJI (relative risk 1.40, 95% confidence interval [CI] 1.08-1.82, P = .01). There was no difference in risk between the groups associated with education level or median household income (all, P > .05). First-degree relatives of patients who develop PJI (hazard ratio 1.66, 95% CI 1.23-2.24, P = .001) and first-degree and second-degree relatives combined (hazard ratio 1.39, 95% CI 1.09-1.77, P = .007) were at greater risk despite controlling for the above socioeconomic factors.ConclusionOur study provides further support that genetic factors may underlie PJI as we did observe significant familial risk even after accounting for socioeconomic factors and payer status. We did not find a correlation between education level or household income and PJI; however, Medicaid payees were at increased risk. Continued study is needed to define a possible heritable disposition to PJI in an effort to optimize treatment and possibly prevent this complication.     

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.     

Weight-Based Aspirin Dosing May Further Reduce the Incidence of Venous Thromboembolism Following Primary Total Joint Arthroplasty

BackgroundObesity poses a challenge to thromboembolic prophylaxis following total joint arthroplasty (TJA). The purpose of this study is to evaluate a weight-based aspirin dosing regimen for prevention of venous thromboembolism (VTE) following TJA.MethodsThis is a retrospective observational study of 2403 patients who underwent primary total hip or knee arthroplasty at one institution. A weight-based aspirin dosing regimen for VTE prophylaxis was administered to 1247 patients: patients weighing ≥120 kg received 325 mg aspirin twice daily (BID) and those weighing <120 kg received 81 mg aspirin BID for 4 weeks. In total, 1156 patients in the comparison cohort received 81 mg aspirin BID. VTE and gastrointestinal bleeding events were identified through chart review at 42 days and 6 months postoperatively. A multivariable logistic regression was performed to adjust for covariates.ResultsThe weight-based aspirin cohort had a significantly lesser incidence of VTE at 42 days (P = .03, relative risk [RR] 0.31, 95% confidence interval 0.12-0.82) and 6 months (P = .03, RR 0.38, 95% confidence interval 0.18-0.80). There was no difference in VTE incidence between total hip arthroplasty and total knee arthroplasty cases (P = .8). There was no difference in gastrointestinal bleeding events between the cohorts at 42 days (P = .69) or 6 months (P = .92). Subanalysis of patients weighing ≥120 kg demonstrated a significant difference between the cohorts with a VTE incidence of 3.48% and 0% in the 81 mg and weight-based cohorts, respectively (P = .02).ConclusionPatients prescribed a weight-based aspirin regimen had significantly fewer VTEs after TJA compared to historical controls with an RR reduction of 69% at 6 weeks and 62% at 6 months postoperatively. This suggests the need to factor patient weight when determining postoperative VTE prophylaxis with aspirin.     

Low-Dose Aspirin Is Safe and Effective for Venous Thromboembolism Prevention in Patients Undergoing Revision Total Hip Arthroplasty: A Retrospective Cohort Study

BackgroundCurrently, there is no established universal standard of care for prophylaxis against venous thromboembolism (VTE) in orthopedic patients undergoing revision total hip arthroplasty (rTHA). The aim of this study is to determine whether a protocol of 81-mg aspirin (ASA) bis in die (BID) is safe and/or effective in preventing VTE in patients undergoing rTHAs vs 325-mg ASA BID.MethodsIn 2017, a large academic medical center adopted a new protocol for VTE prophylaxis in arthroplasty patients at standard risk. Initially, patients received 325-mg ASA BID but switched to 81-mg ASA BID. A retrospective review (2011-2019) was performed to identify 1361 consecutive rTHA patients and their associated 90-day postoperative complications such as VTE, including pulmonary embolism (PE) and/or deep vein thrombosis (DVT), as the primary outcome; and gastrointestinal and wound bleeding, acute periprosthetic joint infection, and mortality as the secondary outcome.ResultsFrom 2011 to 2017, 973 rTHAs were performed and 13 total VTE cases were diagnosed (1.34%). From 2017 to 2019, 388 rTHAs were performed with 3 total VTE cases identified (0.77%). Chi-squared analyses and logistic regression models showed no differences in rates or odds in postoperative PE (P = .09), DVT (P = .79), PE and DVT (P = .85), and total VTE (P = .38) using either dose. There were also no differences between bleeding complications (P = .14), infection rate (P = .46), and mortality (P = .53).ConclusionUsing a protocol of 81-mg of ASA BID is noninferior to 325-mg ASA BID and may be safe and effective in maintaining low rates of VTE in patients undergoing rTHA.     

The Impact of Exchanging Cerclage Fixation after Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty for Periprosthetic Joint Infection

BackgroundAn extended trochanteric osteotomy (ETO) is a powerful tool for femoral component revision. There is limited evidence that directly supports its use in the setting of a periprosthetic joint infection (PJI). Cerclage fixation raises the theoretical concern for persistent infection.MethodsOur institutional database included 76 ETOs for revision hip arthroplasty between January 1, 2008 and December 31, 2019. The cohort was divided based on indication for femoral component revision: PJI versus aseptic revision. The PJI group was subdivided based on second-stage exchange versus retention of initial cerclage fixation. Operative time, estimated blood loss, complications, and rate of repeat revision surgery were evaluated.ResultsForty-nine patients (64%) underwent revision for PJI and 27 patients (36%) underwent aseptic revision. There was no significant difference in operative times (P = .082), postoperative complications (P = .258), or rate of repeat revision surgery (P = .322) between groups. Of the 49 patients in the PJI group, 40 (82%) retained cerclage fixation while 9 (18%) had cerclage exchange. Cerclage exchange did not significantly impact operative time (P = .758), blood loss (P = .498), rate of repeat revision surgery (P = .302), or postoperative complications (P = .253) including infection (P = .639).ConclusionAn ETO remains a powerful tool for femoral component removal, even in the presence of a PJI. A multi-institutional investigation would be required to validate observed trends toward better infection control with cerclage exchange. Cerclage exchange did not appear to increase operative time, blood loss, or postoperative complication rates.     

Outcome and Predictors of Septic Failure Following Total Joint Arthroplasty for Prior Septic Arthritis of Hip and Knee Joint

BackgroundArthroplasty patients with prior septic arthritis are at a high risk of developing periprosthetic joint infection (PJI). The aims of this study are to investigate the outcome and predictors of septic failure following total joint arthroplasty (TJA) for prior septic arthritis. In addition, the optimal timing of TJA is also discussed.MethodsA retrospective review of 105 TJA patients with prior septic arthritis between January 2000 and December 2019 was performed. Patient-specific and surgery-related factors, organism profiles, and other relevant variables were recorded.ResultsAt a mean follow-up of 10.3 years, the PJI rate was 16.2%. The adjusted Cox proportional hazards model showed that male gender (HR, 9.95; P < .01), end-stage renal disease (HR, 37.34; P < .01), debridement surgery ≥3 times (HR,4.75; P = .04) and polymicrobial infection in primary septic arthritis (HR, 10.02; P = .02) were independent risk factors for PJI. Neither the types of initial debridement, nor one-stage vs two-stage arthroplasty was related to the risk of PJI. While delaying the timing of TJA did not correlate with a reduction of PJI rate, there was a higher risk of PJI re-infection by the same microorganisms isolated in prior septic arthritis if TJA was performed within 6 months after septic arthritis.ConclusionsOur study demonstrated that male gender, end-stage renal disease (ESRD), multiple debridement surgeries and polymicrobial septic arthritis predisposed septic failure of TJA following prior septic arthritis. Surgeons should counsel patients with the potential complications, and be cognizant about the risk factors pertaining to septic failure when considering TJA.     

Surgical Helmet Systems Are Associated With a Lower Rate of Prosthetic Joint Infection After Total Knee Arthroplasty: Combined Results From the New Zealand Joint Registry and Surgical Site Infection Improvement Programme

BackgroundThis study aimed to identify the risk factors, in particular the use of surgical helmet systems (SHSs), for prosthetic joint infection (PJI) after total knee arthroplasty (TKA). Data recorded by the New Zealand Surgical Site Infection Improvement Programme (SSIIP) and the New Zealand Joint Registry (NZJR) were combined and analyzed.MethodsPrimary TKA procedures performed between July 2013 and June 2018 that were recorded by both the SSIIP and NZJR were analyzed. Two primary outcomes were measured: (1) PJI within 90 days as recorded by the SSIIP and (2) revision TKA for deep infection within 6 months as recorded by the NZJR. Univariate and multivariate analyses were performed to identify risk factors for both outcomes with results considered significant at P < .05.ResultsA total of 19,322 primary TKAs were recorded by both databases in which 97 patients had a PJI within 90 days as recorded by the SSIIP (0.50%), and 90 patients had a revision TKA for deep infection within 6 months (0.47%) as recorded by the NZJR. An SHS was associated with a lower rate of PJI (adjusted odds ratio [OR] = 0.50, P = .008) and revision for deep infection (adjusted OR = 0.55, P = .022) than conventional gowning. Male sex (adjusted OR = 2.6, P < .001) and an American Society of Anesthesiologists score >2 were patient risk factors for infection (OR = 2.63, P < .001 for PJI and OR = 1.75, P = .017 for revision for deep infection).ConclusionUsing contemporary data from the SSIIP and NZJR, the use of the SHS was associated with a lower rate of PJI after primary TKA than conventional surgical gowning. Male sex and a higher American Society of Anesthesiologists score continue to be risk factors for infection.     

Utility of Diagnostic Markers in Late Periprosthetic Joint Infection Workup for Total Knee Arthroplasty Patients Who Received Antibiotics 48 Hours Before Aspiration

BackgroundDiagnosing periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) remains challenging despite recent advancements in testing and evolving criteria over the last decade. Moreover, the effects of antibiotic use on diagnostic markers are not fully understood. Thus, this study sought to determine the influence of antibiotic use within 48 hours before knee aspiration on synovial and serum laboratory values for suspected late PJI.MethodsPatients who underwent a TKA and subsequent knee arthrocentesis for PJI workup at least 6 weeks after their index arthroplasty were reviewed across a single healthcare system from 2013 to 2020. Median synovial white blood cell (WBC) count, synovial polymorphonuclear (PMN) percentage, serum erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP), and serum WBC count were compared between immediate antibiotic and nonantibiotic PJI groups. Receiver operating characteristic (ROC) curves and Youden’s index were used to determine test performance and diagnostic cutoffs for the immediate antibiotics group.ResultsThe immediate antibiotics group had significantly more culture-negative PJIs than the no antibiotics group (38.1 versus 16.2%, P = .0124). Synovial WBC count demonstrated excellent discriminatory ability for late PJI in the immediate antibiotics group (area under curve, AUC = 0.97), followed by synovial PMN percentage (AUC = 0.88), serum CRP (AUC = 0.86), and serum ESR (AUC = 0.82).ConclusionAntibiotic use immediately preceding knee aspiration should not preclude the utility of synovial and serum lab values for the diagnosis of late PJI. Instead, these markers should be considered thoroughly during infection workup considering the high rate of culture-negative PJI in these patients.Level of EvidenceLevel III, retrospective comparative study.     

Synovial Fluid Absolute Neutrophil Count and Neutrophil-To-Lymphocyte Ratio are not Superior to Polymorphonuclear Percentage in Detecting Periprosthetic Joint Infection

BackgroundSerum and synovial biomarkers are currently used to diagnose periprosthetic joint infection (PJI). Serum neutrophil-to-lymphocyte ratio (NLR) has shown promise as an inexpensive test in diagnosing infection, but there are no reports of synovial NLR or absolute neutrophil count (ANC) for diagnosing chronic PJI. The purpose of this study was to investigate the diagnostic potential of both markers.MethodsA retrospective review of 730 patients who underwent total joint arthroplasty and subsequent aspiration was conducted. Synovial white blood cell (WBC) count, synovial polymorphonuclear percentage (PMN%), synovial NLR, synovial ANC, serum erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP), serum WBC, serum PMN%, serum NLR, and serum ANC had their utility in diagnosing PJI examined by area-under-the-curve analyses (AUC). Pairwise comparisons of AUCs were performed.ResultsThe AUCs for synovial WBC, PMN%, NLR, and ANC were 0.84, 0.84, 0.83, and 0.85, respectively. Synovial fluid ANC was a superior marker to synovial NLR (P = .027) and synovial WBC (P = .003) but not PMN% (P = .365). Synovial NLR was inferior to PMN% (P = .006) but not different from synovial WBC (P > .05). The AUCs for serum ESR, CRP, WBC, PMN%, NLR, and ANC were 0.70, 0.79, 0.63, 0.72, 0.74, and 0.67, respectively. Serum CRP outperformed all other serum markers (P < .05) except for PMN% and NLR (P > .05). Serum PMN% and NLR were similar to serum ESR (P > .05).ConclusionSynovial ANC had similar performance to PMN% in diagnosing chronic PJI, whereas synovial NLR was a worse diagnostic marker. The lack of superiority to synovial PMN% limits the utility of these tests compared to established criteria.     

Trends of Prosthetic Joint Infection Organisms and Recurrence for a Single High-Volume Arthroplasty Surgeon Over 20 Years

BackgroundProsthetic joint infection (PJI) is a morbid complication following total joint arthroplasty (TJA). PJI diagnosis and treatment has changed over time, and patient co-management with a high-volume musculoskeletal infectious disease (MSK ID) specialist has been implemented at our institution in the last decade.MethodsWe retrospectively evaluated all consecutive TJA patients treated for PJI between 1995 and 2018 by a single high-volume revision TJA surgeon. Microbial identities, antibiotic resistance, prior PJI, and MSK ID consultation were investigated.ResultsIn total, 261 PJI patients (median age 66 years, interquartile range 57-75) were treated. One-year and 5-year reinfection rates were 15.8% (95% confidence interval [CI] 11.6-20.7) and 22.1% (95% CI 17.0-27.7), respectively. Microbial identities and antibiotic resistances did not change significantly over time. Despite seeing more prior PJI patients (53.3% vs 37.6%, P = .012), MSK ID-managed patients had similar infection rates as non-MSK ID-managed patients (hazard ratio [HR] 1.02, 95% CI 0.6-1.75, P = .93). Prior PJI was associated with higher reinfection risk (HR 2.39, 95% CI 1.39-4.12, P = .002) overall and in patients without MSK ID consultation, specifically (HR 2.78, 95% CI 1.37-5.65, P = .005). This risk was somewhat lower and did not reach significance in prior PJI patients with MSK ID consultation (HR 1.97, 95% CI 0.87-4.48, P = .106).ConclusionWe noted minimal differences in microbial/antibiotic resistances for PJI over 20 years in a single institution, suggesting current standards of PJI treatment remain encouragingly valid in most cases. MSK ID involvement was not associated with lower reinfection risk overall; however, in patients with prior PJI, the risk of reinfection appeared to be somewhat lower with MSK ID involvement.Level of EvidenceLevel IV–Case Series.     

Use of Antimicrobial-Impregnated Incise Drapes to Prevent Periprosthetic Joint Infection in Primary Total Joint Arthroplasty: A Retrospective Analysis of 9774 Cases

BackgroundAntimicrobial-impregnated incise drapes are often used despite any literature that demonstrates a reduction in the rate of periprosthetic joint infection (PJI). The aim of this study is to compare the efficacy of antimicrobial-impregnated incise drapes with nonantimicrobial-impregnated incise drapes for the prevention of PJI in patients undergoing total joint arthroplasty (TJA).MethodsA retrospective study of 9774 primary TJAs from 2000 to 2012 was performed. Patients who received an antimicrobial-impregnated incise drape (n = 5241) were compared with patients who received a nonantimicrobial-impregnated incise drape (n = 4533). The decision to use an antimicrobial drape was based on the surgeon’s discretion. Patients who developed PJI within 1 year after index surgery were identified. Multivariate logistic regression analysis and sensitivity analysis using propensity score matching were performed to control for potential confounders.ResultsThe overall PJI rate was 1.14% (60 of 5241) for patients who received an antimicrobial-impregnated incise drape compared with 1.26% (57 of 4533) for those with a nonantimicrobial-impregnated incise drape. There was no difference in the PJI rate between patients with an antimicrobial-impregnated incise drape and those who received nonantimicrobial-impregnated incise drape in the univariate (odds ratio [OR] = 0.91; 95% confidence interval [CI] = 0.63-1.30), multivariate (adjusted OR = 0.92; 95% CI, 0.63-1.34), or propensity score matching analysis (OR = 0.84; 95% CI = 0.52-1.35).ConclusionDespite the increasing adoption of the use of antimicrobial-impregnated incise drapes in our institute, this study suggests that antimicrobial-impregnated incise drapes do not reduce PJI in patients undergoing primary TJAs.     

D-Dimer,Erythrocyte Sedimentation Rate,and C-Reactive Protein Sensitivities for Periprosthetic Joint Infection Diagnosis

BackgroundThere is contradicting evidence on the diagnostic value of inflammatory biomarkers for periprosthetic joint infection (PJI). We sought to quantify the sensitivity of D-dimer for acute and chronic PJI diagnosis and evaluate D-dimer lab values in the 90-day postoperative window in a control cohort of primary joint arthroplasty patients for comparison.MethodsAn institutional database was queried for patients undergoing revision procedures for PJI after total hip arthroplasty (THA) and total knee arthroplasty (TKA) from 2014 to present. CRP, ESR, and D-dimer were collected within 90 days pre and postoperatively and sensitivities for the diagnosis of PJI were calculated. The control group included patients who underwent a negative diagnostic workup for deep venous thrombosis (DVT) or pulmonary embolus (PE) and had a D-dimer lab collected within 90 days postoperatively from primary total joint arthroplasty (TJA).ResultsA total of 604 PJI patients were identified, and 81 patients had D-dimer, ESR, and CRP collected. There were 50/81 acute PJI patients and 31/81 chronic PJI patients who had median D-dimer values of 2,136.5 ng/mL [interquartile range (IQR): 1,642-3,966.5] and 3,336 ng/mL [IQR: 1,976-5,594]. Only the chronic PJI group had significantly higher D-dimer values when compared to the control cohort (P = .009). The sensitivity of D-dimer was calculated to be 92% and 93.5% in the acute and chronic PJI groups, respectively.ConclusionSerum D-dimer may not have high diagnostic utility for acute PJI, especially in the setting of recent surgery; however, it still may be useful for patients who have chronic PJI.