Fracture-Associated Microbiome and Persistent Nonunion: Next-Generation Sequencing Reveals New Findings.

INTRODUCTION: Fracture nonunion remains a devastating complication and may occur for several reasons, though the microbial contribution remains poorly estimated. Next-generation sequencing (NGS) techniques, including 16S rRNA gene profiling, are capable of rapid bacterial detection within clinical specimens. Nonunion cases may harbor microbes that escape detection by conventional culture methods that contribute to persistence. Our aim was to investigate the application of NGS pathogen detection to nonunion diagnosis. METHODS: In this prospective multicenter study, samples were collected from 54 patients undergoing open surgical intervention for preexisting long-bone nonunion (n = 37) and control patients undergoing fixation of an acute fracture (n = 17). Intraoperative specimens were sent for dual culture and 16S rRNA gene-based microbial profiling. Patients were followed for evidence of fracture healing, whereas patients not healed at follow-up were considered persistent nonunion. Comparative analyses aimed to determine whether microbial NGS diagnostics could discriminate between nounions that healed during follow-up versus persistent nonunion. RESULTS: Positive NGS detection was significantly correlated with persistent nonunion, positive in 77% more cases than traditional culture. Nonunion cases were observed to have significantly increased diversity and altered bacterial profiles from control cases. DISCUSSION: NGS seems to be a useful adjunct in identification of organisms that may contribute to nonunion. Our findings suggest that the fracture-associated microbiome may be a significant risk factor for persistent nonunion. Ongoing work aims to determine the clinical implications of isolated organisms detected by sequencing and to identify robust microbial predictors of nonunion outcomes. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Worse Outcomes Are Associated With Proximal Femoral Replacement Following Periprosthetic Joint Infection.

BACKGROUND: Proximal femoral replacements (PFRs) are often used in the setting of severe bone loss. As osteolysis has become less common, PFR may be used to address other causes of bone loss such as infection or periprosthetic fracture. The aim of this study is to investigate the clinical outcomes of PFR for non-neoplastic conditions. METHODS: A retrospective review of 46 patients undergoing PFR at a single institution was performed. The electronic records were reviewed to extract relevant information including the reason for use of PFR, surgical variables, follow-up, and complications. Survivorship curves were generated and differences in survivorship were evaluated using the log-rank test. Radiographic evaluation was also performed. RESULTS: Using revision as an endpoint, the Kaplan-Meier analysis of the entire cohort demonstrated a survival rate of 74% at 1 year and 67% at 5 years. Patients with a preoperative diagnosis of periprosthetic joint infection demonstrated the lowest survivorship with a failure rate of 47%. Furthermore, a high dislocation rate at 17.4% (n = 8) was observed. The use of dual-mobility articulation was effective in reducing dislocation. CONCLUSION: PFR is a valuable reconstructive option for patients with massive proximal femoral bone loss. This study demonstrates that patients with periprosthetic joint infection who undergo PFR reconstruction are at very high risk of subsequent failure, most commonly from reinfection and instability. The use of a dual-mobility articulation in association with PFR appears to help mitigate risk of subsequent dislocation.

Interim Spacer Exchange for Treatment of Periprosthetic Joint Infection: Almost Half the Patients Subsequently Fail.

BACKGROUND: Interim spacer exchange may be performed in patients undergoing 2-stage exchange for periprosthetic joint infection. Several studies have demonstrated that interim spacer exchange is associated with poor outcomes. This study investigated the survivorship and risk factors for failure in patients with an interim spacer exchange. METHODS: Two institutional databases identified 182 patients who underwent spacer exchange from 2000 to 2017. Primary outcomes included progression to reimplantation, treatment success, and mortality. Bivariate analysis was performed to evaluate risk factors associated with failure. Kaplan-Meier curves using host and local grades were generated to evaluate for primary outcomes and differences in survivorship. RESULTS: The overall failure rate was 49% in patients with a spacer exchange. Most patients (60%) failed before 2 years. Higher comorbidity scores, elevated erythrocyte sedimentation rate, and non-White race were more prevalent in patients who failed. Negative cultures at the time of exchange were more prevalent in patients who did not fail. Failure rate was higher in immunocompromised conditions, and those who had revision prior to exchange. After considering clinically relevant variables, advanced host grade C was the single factor associated with treatment failure. Although survivorship curves were not significantly different between extremity local grades, higher host grades were associated with treatment failure. CONCLUSION: Almost 1 out of 2 patients with spacer exchange were found to fail the intended 2-stage revision arthroplasty. Benefits of delivering additional antibiotic load with a new spacer should be balanced against poor outcomes in patients with the aforementioned risk factors.

Association of Perioperative Red Blood Cell Transfusion With Symptomatic Venous Thromboembolism Following Total Hip and Knee Arthroplasty.

BACKGROUND: Prior registry data suggest that perioperative red blood cell (RBC) transfusion may increase the incidence of venous thromboembolism (VTE) in patients status post surgery. However, there are limited data that explore VTE risk after perioperative transfusion in the setting of primary total joint arthroplasty (TJA). Our aim is to investigate the association between perioperative RBC transfusion and the development of symptomatic VTE after adjusting for confounding variables. METHODS: We retrospectively reviewed all patients undergoing primary TJA at a single institution from 2001 to 2016. The primary outcome was development of symptomatic VTE (deep vein thrombosis or pulmonary embolism) up to 90 days following primary TJA. To identify the association between RBC transfusion and development of VTE, univariate and multivariate analyses were used, as well as a sensitivity analysis using propensity score matching based on patient comorbidities. RESULTS: Of the 29,003 patients who underwent TJA, 2500 (8.62%) received RBC transfusion perioperatively and 302 (1.04%) developed a postoperative VTE within 90 days of surgery. While univariate analysis did suggest a slightly increased incidence of VTE in association with RBC transfusion (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.09-2.16), this difference was eliminated when multivariate analysis (OR, 0.42; 95% CI, 0.12-1.39) and propensity score matching (propensity-matched OR, 1.2; 95% CI, 0.7-1.8) were employed. CONCLUSION: Perioperative RBC transfusion does not significantly increase the incidence of symptomatic VTE following primary TJA in the 90-day postoperative period after adjustment for host VTE risk scores and other confounding variables. Perioperative RBC transfusion may be safely administered if indicated following total hip and knee arthroplasty.

Understanding Opioid Use After Total Hip Arthroplasty: A Comprehensive Analysis of a Mandatory Prescription Drug Monitoring Program.

INTRODUCTION: Opioids remain the most prescribed medication after total hip arthroplasty (THA) despite the potential for abuse and adverse effects. Given the high rates of opioid abuse and potential adverse effects, the reporting of controlled substances is now mandatory in many statewide databases. This study aimed to use a mandatory statewide database to analyze opioid prescription patterns in postoperative THA patients and identify independent risk factors for those patients who need a second prescription and/or require prolonged use (>6 months). METHODS: We retrospectively reviewed a consecutive series of 619 primary THAs. Demographic and comorbidity information were collected for all patients. Narcotic prescription data (converted to morphine milligram equivalents) as well as prescription data for sedatives, benzodiazepines, and stimulants were collected from the State's Controlled Substance Monitoring websites 6 months before and 9 months after the index procedure. Bivariate and multivariate analyses were done for second prescription and continued use. RESULTS: Of the 619 patients who underwent THA, 34.9% (216/619) used preoperative opioids, 36.2% (224/619) filled a second opioid prescription, and 10.5% (65/619) had continued use past 6 months. Patients with preoperative opioids were at an approximately 4-fold increased odds of requiring a second script and 12 times odds of continued opioid use. In the multivariate analysis, independent risk factors for requiring a second prescription, in descending order of magnitude, included the use of any sedative or sleep aid prescription and preoperative narcotic use. Independent risk factors for continued narcotic use longer than 6 months after THA included preoperative narcotic use and increased length of stay. DISCUSSION: Several risk factors and their relative weight have been identified for continued narcotic consumption after THA. It is important for surgeons to consider these predisposing factors preoperatively during the informed consent process and for managing postoperative pain expectations.

Treatment Outcomes and Attrition in Gram-Negative Periprosthetic Joint Infection.

BACKGROUND: While the prevailing belief is that periprosthetic joint infection (PJI) caused by Gram-negative (GN) organisms confers a poorer prognosis than Gram-positive (GP) cases, the current literature is sparse and inconsistent. The purpose of this study is to compare the treatment outcomes for GN PJI vs GP PJI and Gram-mixed (GM) PJI. METHODS: A retrospective review of 1189 PJI cases between 2007 and 2017 was performed using our institutional PJI database. Treatment failure defined by international consensus criteria was compared between PJI caused by GN organisms (n = 45), GP organisms (n = 663), and GM (n = 28) cases. Multivariate regression was used to predict time to failure. RESULTS: GM status, but not GN, had significantly higher rates of treatment failure compared to GP PJI (67.9% vs 33.2% failure; hazards ratio [HR] = 2.243, P = .004) in the multivariate analysis. In a subanalysis of only the 2-stage exchange procedures, both GN and GM cases were significantly less likely to reach reimplantation than GP cases (HR = .344, P < .0001; HR = .404, P = .013). CONCLUSION: Although there was no observed difference in the overall international consensus failure rates between GN (31.1% failure) and GP (33.2%) PJI cases, there was significant attrition in the 2-stage exchange GN cohort, and these patients were significantly less likely to reach reimplantation. Our findings corroborate the prevailing notion that GN PJI is associated with poorer overall outcomes vs GP PJI. These data add to the current body of literature, which may currently underestimate the overall failure rates of GN PJI treated via 2-stage exchange and fail to identify pre-reimplantation morbidity.

A Novel Adjunct Indicator of Periprosthetic Joint Infection: Platelet Count and Mean Platelet Volume.

BACKGROUND: Diagnosing a periprosthetic joint infection (PJI) is difficult and often requires a combination of objective findings. The purpose of this study is to determine whether platelets, a known acute phase reactant, would be able to further aid in the diagnosis of PJI. METHODS: A single-institution retrospective review study was performed on all revision total hip and knee arthroplasties done between 2000 and 2016 (n = 4939). PJI was defined by Musculoskeletal Infection Society criteria (n = 949). Platelet count and mean platelet volume were assessed from each patient's preoperative complete blood count. These values were then assessed as a ratio via receiver operating characteristic (ROC) curve analysis. RESULTS: The platelet count to mean platelet volume ratio for PJI patients was 33.45 compared to 25.68 for patients in the aseptic revision cohort (P < .001). ROC curve analysis demonstrates that a ratio of 31.70 has a sensitivity of 48.10 (95% confidence interval 44.9-51.4) and a specificity of 80.85 (95% confidence interval 79.6-82.1). This specificity was higher than that of both estimated sedimentation ratio (ESR) and C-reactive protein (CRP) for the same cohorts using optimal values determined via ROC curve analysis. When used in conjunction with ESR and CRP, there was a statistically significant increase in the diagnostic performance of the model used to assess PJI relative to the model that just employed ESR and CRP (P < .05). CONCLUSION: Our study demonstrates that platelets and their associated serum biomarkers are associated with PJI and warrant consideration in patients who are being evaluated for potential PJI.

Aspirin Thromboprophylaxis Confers No Increased Risk for Aseptic Loosening Following Cementless Primary Hip Arthroplasty.

BACKGROUND: Aspirin has been shown to be a safe and cost-effective thromboprophylaxis agent with equivalent preventive efficacy to warfarin and fewer side-effects. However, animal studies have suggested delayed bone healing with aspirin and other inhibitors of prostaglandin synthesis. The impact of aspirin on aseptic loosening following cementless total hip arthroplasty (THA) has yet to be explored. Our aim was to determine if patients receiving aspirin for thromboprophylaxis had higher rates of aseptic loosening vs patients receiving warfarin after THA. METHODS: We identified 11,262 consecutive primary uncemented THA performed between 2006 and 2017. Postoperatively, either warfarin (target international normalized ratio 1.5-2.0) or aspirin chemoprophylaxis were prescribed for 4 weeks. We recorded demographics, length of stay, body mass index, preoperative nonsteroidal antiinflammatory drug use, and Elixhauser comorbidity index. All revisions because of aseptic loosening within 1 year of the index procedure were identified radiographically, confirmed intraoperatively, and did not fulfill Musculoskeletal Infection Society criteria for periprosthetic infection. Multivariate logistic regression analysis was performed. RESULTS: There was no difference (P = .14) in the rates of revision for aseptic loosening between patients in the aspirin cohort (14/4530; 0.31%; P = .14) and the warfarin cohort (36/6682; 0.54%). After accounting for confounding variables, no significant difference was noted in aseptic loosening rates between patients treated with aspirin vs those treated with warfarin (adjusted odds ratio 0.51; P = .11). Perioperative nonsteroidal antiinflammatory drug was not significantly associated with aseptic loosening (adjusted odds ratio 1.20; P = .67). CONCLUSION: While multiple agents are available for venous thromboprophylaxis, there is increasing evidence in favor of the use of aspirin. This study allays the notion that aspirin increases the rates of aseptic loosening following uncemented hip arthroplasty.

Self-Directed Home Exercises vs Outpatient Physical Therapy After Total Knee Arthroplasty: Value and Outcomes Following a Protocol Change.

BACKGROUND: The need for outpatient physical therapy (OPPT) has been questioned following primary total knee arthroplasty (TKA). Recent studies have suggested that similar outcomes may be possible with self-directed home exercise programs (HEP) compared to OPPT, which can be costly to both the patient and healthcare system. The aim of the present study is to compare the safety, efficacy, and health economics of formal OPPT with self-directed home exercises after TKA following a protocol change. METHODS: A single-surgeon, retrospective study of 520 consecutive patients undergoing primary unilateral TKA from 2016 to 2018 was performed. All 251 TKAs performed in 2016 were routinely prescribed OPPT, while all 269 TKAs in 2017 completed a self-directed HEP alone for 2 weeks. At their 2-week visit, OPPT was prescribed if patients had less than 90° range of motion or per patient request. Financial data of postdischarge costs were collected for all patients. Multivariate logistic regression evaluated for variables associated with failure of the HEP program. RESULTS: Overall, 65.8% (177/269) of patients in the HEP group did not require OPPT. There was no significant difference in percentage of patients whose range of motion was less than 90° at 2-week follow-up between OPPT and HEP (14% vs 11.9%, P = .467). Between OPPT and HEP, there were no differences in manipulation under anesthesia (3.2% vs 3%, P = .883). On average, patients who received OPPT incurred an increase in average cost of $1340.87 and $1893.42 for Medicare and private insurer patients, respectively. We did not identify any significant risk factors for failing HEP. CONCLUSION: Comparable outcomes were demonstrated between patients receiving HEP compared to OPPT with a substantial cost saving. While a portion of patients still require formal OPPT, the majority do not. Surgeons should consider an initial trial of HEP with close follow-up in order to limit unnecessary costs associated with OPPT.

Surgical Treatment of Chronic Periprosthetic Joint Infection: Fate of Spacer Exchanges.

BACKGROUND: Patients with periprosthetic joint infection (PJI) undergoing 2-stage exchange arthroplasty may undergo an interim spacer exchange for a variety of reasons including mechanical failure of spacer or persistence of infection. The objective of this study is to understand the risk factors and outcomes of patients who undergo spacer exchange during the course of a planned 2-stage exchange arthroplasty. METHODS: Our institutional database was used to identify 533 patients who underwent a 2-stage exchange arthroplasty for PJI, including 90 patients with a spacer exchange, from 2000 to 2017. A retrospective review was performed to extract relevant clinical information. Treatment outcomes included (1) progression to reimplantation and (2) treatment success as defined by a Delphi-based criterion. Both univariate and multivariate Cox regression models were performed to investigate whether spacer exchange was associated with failure. Additionally, a propensity score analysis was performed based on a 1:2 match. RESULTS: A spacer exchange was required in 16.9%. Patients who underwent spacer exchanges had a higher body mass index (P < .001), rheumatoid arthritis (P = .018), and were more likely to have PJI caused by resistant (0.048) and polymicrobial organisms (P = .007). Patients undergoing a spacer exchange demonstrated lower survivorship and an increased risk of failure in the multivariate and propensity score matched analysis compared to patients who did not require a spacer exchange. DISCUSSION: Despite an additional load of local antibiotics and repeat debridement, patients who underwent a spacer exchange demonstrated poor outcomes, including failure to undergo reimplantation and twice the failure rate. The findings of this study may need to be borne in mind when managing patients who require spacer exchange.

Perioperative Telephone Encounters Should Be Included in the Relative Value Scale Update Committee Review of Time Spent on Total Hip and Knee Arthroplasty.

BACKGROUND: Providing care for patients undergoing hip and knee arthroplasty requires substantial effort beyond the actual replacement surgery to ensure a safe, clinical, and economically effective outcome. Recently, the Centers for Medicare and Medicaid Services has stated that the procedural codes for total hip (THA) and total knee arthroplasty (TKA) are potentially misvalued and has asked for a review by the Relative Value Scale Update Committee (RUC). The purpose of this study is to quantify one of the additional work efforts associated with telephone encounters during the perioperative episode of care. METHODS: We retrospectively reviewed all 47,841 telephone calls from patients to our office from 2015 to 2017 in a consecutive series of 3309 patients who underwent TKA and 3651 patients who underwent THA. We recorded reasons for communication, amount of communication, and the caller identity for both 30 days preoperatively and 90 days postoperatively. We then used the RUC Building Block Method to calculate the preservice and postservice work included in a review of the time and intensity of the codes for THA and TKA. RESULTS: The average number of preoperative patient calls per patient was 2.31 for TKA and 2.44 for THA, and the average number of postoperative calls was 5.01 for TKA and 4.00 for THA. The most common reasons for patient calls were perioperative care instructions, medications, medical clearance, paperwork/insurance, and complications. Using the RUC-approved work relative value units (wRVUs) assigned to each telephone encounter, an additional 1.83 wRVUs for perioperative telephone encounters for TKA and 1.61 for THA should be assigned. CONCLUSIONS: Providing patients with appropriate support during the arthroplasty episode of care requires substantial telephonic support, which should be acknowledged. As the RUC considers reviewing the time and intensity spent on perioperative care for patients undergoing THA and TKA, they should consider appropriately documenting the amount of work required for telephone communication.

The Economics of Antibiotic Cement in Total Knee Arthroplasty: Added Cost with No Reduction in Infection Rates.

BACKGROUND: To reduce the substantial clinical and financial burden of periprosthetic joint infection (PJI), some surgeons advocate for the use of antibiotic-loaded bone cement (ALBC) in primary total knee arthroplasty (TKA), although its effectiveness continues to be debated in the literature. The purpose of this study was to determine whether the routine use of ALBC is cost-effective in reducing PJI after primary TKA. METHODS: We retrospectively reviewed a consecutive series of patients undergoing cemented primary TKA at two hospitals within our institution from 2015 to 2017. We compared demographics, comorbidities, costs, and PJI rates between patients receiving ALBC and plain cement. We performed a multivariate regression analysis to determine the independent effect of ALBC on PJI rate. We calculated readmission costs for PJI and reduction in PJI needed to justify the added cost of ALBC. RESULTS: Of 2511 patients, 1077 underwent TKA with ALBC (43%), with no difference in PJI rates (0.56% vs 0.14%, P = .0662) or complications (1.2% vs 1.6%, P = .3968) but higher cement costs ($416 vs $117, P < .0001) and overall procedure costs ($6445 vs $5.968, P < .0001). ALBC had no effect on infection rate (P = .0894). Patients readmitted with PJI had higher overall 90-day episode-of-care claims costs ($49,341 vs $19,032, P < .001). To justify additional costs, ALBC would need to prevent infection in one of every 101 patients. CONCLUSION: Routine use of ALBC in primary TKA is not cost-effective, adding $299 to the cost of episode of care without a reduction in PJI rate. Further study is needed to determine whether select use of ALBC would be justified in high-risk patients.

Intraoperative Ketamine in Total Knee Arthroplasty Does Not Decrease Pain and Narcotic Consumption: A Prospective Randomized Controlled Trial.

BACKGROUND: Multiple studies have demonstrated that ketamine, a glutamate receptor blocker, may decrease postoperative pain in abdominal and orthopedic surgeries. However, its role with spinal anesthesia and total knee arthroplasty (TKA) remains unknown. The purpose of this study is to determine the efficacy of subanesthetic dosing of ketamine during TKA on postoperative pain and narcotic consumption. METHODS: In this prospective, randomized, double-blinded clinical trial, we enrolled 91 patients undergoing primary TKA with spinal anesthesia in a single institution from 2017 to 2018. Patients were randomized to receive intraoperative ketamine infusion at a rate of 6 mcg/kg/min for 75 minutes or a saline placebo. All patients received spinal anesthesia and otherwise identical surgical approaches, pain management, and rehabilitation protocols. Patient-reported visual analog pain scores were calculated preoperatively, postoperative days (POD) 0-7, and 2 weeks. Narcotic consumption was evaluated on POD 0 and 1. RESULTS: There was no difference in average pain between ketamine and placebo at all time points except for at PODs 1 (45 vs 56, P = .041) and 4 (39 vs 49, P = .040). For least pain experienced, patients administered with ketamine experienced a reduction in pain only at POD 4 (22 vs 35, P = .011). There was no difference in maximum pain cohorts at all time points of the study or in-hospital morphine equivalents between the 2 cohorts. CONCLUSION: As part of multimodal pain management protocol, intraoperative ketamine does not result in a clinically significant improvement in pain and narcotic consumption following TKA.

Risk Adjustment Is Necessary in Value-Based Payment Models for Arthroplasty for Oncology Patients.

BACKGROUND: Value-based payment models such as bundled payments have been introduced to reduce costs following total hip arthroplasty (THA). Concerns exist, however, about access to care for patients who utilize more resources. The purpose of this study is thus to compare resource utilization and outcomes of patients undergoing THA for malignancy with those undergoing THA for fracture or osteoarthritis. METHODS: We queried the American College of Surgeons National Surgical Quality Improvement Program database to identify all hip arthroplasties performed from 2013 to 2016 for a primary diagnosis of malignancy (n = 296), osteoarthritis (n = 96,480), and fracture (n = 13,406). The rates of readmissions, reoperations, comorbidities, mortality, and surgical characteristics were compared between the 3 cohorts. To control for confounding variables, a multivariate analysis was performed to identify independent risk factors for resource utilization and outcomes following THA. RESULTS: Patients undergoing THA for malignancy had a longer mean operative time (155.7 vs 82.9 vs 91.0 minutes, P < .001), longer length of stay (9.0 vs 7.2 vs 2.6 days, P < .001), and were more likely to be discharged to a rehabilitation facility (42.1% vs 61.8% vs 20.2%, P < .001) than patients with fracture or osteoarthritis. When controlling for demographics and comorbidities, patients undergoing THA for malignancy had a higher rate of readmission (adjusted odds ratio 3.39, P < .001) and reoperation (adjusted odds ratio 3.71, P < .001). CONCLUSION: Patients undergoing THA for malignancy utilize more resources in an episode-of-care and have worse outcomes. Risk adjustment is necessary for oncology patients in order to prevent access to care problems for these high-risk patients.

Cefazolin Prophylaxis for Total Joint Arthroplasty: Obese Patients Are Frequently Underdosed and at Increased Risk of Periprosthetic Joint Infection.

BACKGROUND: One of the most effective prophylactic strategies against periprosthetic joint infection (PJI) is administration of perioperative antibiotics. Many orthopedic surgeons are unaware of the weight-based dosing protocol for cefazolin. This study aimed at elucidating what proportion of patients receiving cefazolin prophylaxis are underdosed and whether this increases the risk of PJI. METHODS: A retrospective study of 17,393 primary total joint arthroplasties receiving cefazolin as perioperative prophylaxis from 2005 to 2017 was performed. Patients were stratified into 2 groups (underdosed and adequately dosed) based on patient weight and antibiotic dosage. Patients who developed PJI within 1 year following index procedure were identified. A bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify risk factors for PJI. RESULTS: The majority of patients weighing greater than 120 kg (95.9%, 944/984) were underdosed. Underdosed patients had a higher rate of PJI at 1 year compared with adequately dosed patients (1.51% vs 0.86%, P = .002). Patients weighing greater than 120 kg had higher 1-year PJI rate than patients weighing less than 120 kg (3.25% vs 0.83%, P < .001). Patients who were underdosed (odds ratio, 1.665; P = .006) with greater comorbidities (odds ratio, 1.259; P < .001) were more likely to develop PJI at 1 year. CONCLUSION: Cefazolin underdosing is common, especially for patients weighing more than 120 kg. Our study reports that underdosed patients were more likely to develop PJI. Orthopedic surgeons should pay attention to the weight-based dosing of antibiotics in the perioperative period to avoid increasing risk of PJI.

The 2018 Definition of Periprosthetic Hip and Knee Infection: An Evidence-Based and Validated Criteria.

BACKGROUND: The introduction of the Musculoskeletal Infection Society (MSIS) criteria for periprosthetic joint infection (PJI) in 2011 resulted in improvements in diagnostic confidence and research collaboration. The emergence of new diagnostic tests and the lessons we have learned from the past 7 years using the MSIS definition, prompted us to develop an evidence-based and validated updated version of the criteria. METHODS: This multi-institutional study of patients undergoing revision total joint arthroplasty was conducted at 3 academic centers. For the development of the new diagnostic criteria, PJI and aseptic patient cohorts were stringently defined: PJI cases were defined using only major criteria from the MSIS definition (n = 684) and aseptic cases underwent one-stage revision for a noninfective indication and did not fail within 2 years (n = 820). Serum C-reactive protein (CRP), D-dimer, erythrocyte sedimentation rate were investigated, as well as synovial white blood cell count, polymorphonuclear percentage, leukocyte esterase, alpha-defensin, and synovial CRP. Intraoperative findings included frozen section, presence of purulence, and isolation of a pathogen by culture. A stepwise approach using random forest analysis and multivariate regression was used to generate relative weights for each diagnostic marker. Preoperative and intraoperative definitions were created based on beta coefficients. The new definition was then validated on an external cohort of 222 patients with PJI who subsequently failed with reinfection and 200 aseptic patients. The performance of the new criteria was compared to the established MSIS and the prior International Consensus Meeting definitions. RESULTS: Two positive cultures or the presence of a sinus tract were considered as major criteria and diagnostic of PJI. The calculated weights of an elevated serum CRP (>1 mg/dL), D-dimer (>860 ng/mL), and erythrocyte sedimentation rate (>30 mm/h) were 2, 2, and 1 points, respectively. Furthermore, elevated synovial fluid white blood cell count (>3000 cells/µL), alpha-defensin (signal-to-cutoff ratio >1), leukocyte esterase (++), polymorphonuclear percentage (>80%), and synovial CRP (>6.9 mg/L) received 3, 3, 3, 2, and 1 points, respectively. Patients with an aggregate score of greater than or equal to 6 were considered infected, while a score between 2 and 5 required the inclusion of intraoperative findings for confirming or refuting the diagnosis. Intraoperative findings of positive histology, purulence, and single positive culture were assigned 3, 3, and 2 points, respectively. Combined with the preoperative score, a total of greater than or equal to 6 was considered infected, a score between 4 and 5 was inconclusive, and a score of 3 or less was not infected. The new criteria demonstrated a higher sensitivity of 97.7% compared to the MSIS (79.3%) and International Consensus Meeting definition (86.9%), with a similar specificity of 99.5%. CONCLUSION: This study offers an evidence-based definition for diagnosing hip and knee PJI, which has shown excellent performance on formal external validation.

Incise Draping Reduces the Rate of Contamination of the Surgical Site During Hip Surgery: A Prospective, Randomized Trial.

BACKGROUND: Iodophor-impregnated adhesive incise drapes are widely used during surgeries for reducing surgical site contamination. There is little evidence to support the latter belief. This study evaluated the efficacy of iodophor-impregnated adhesive drapes for reducing bacterial contamination and counts at the incision site during hip surgery. METHODS: In this prospective, randomized clinical trial, we enrolled 101 patients undergoing open joint preservation procedure of the hip. Half the patients had the adhesive drape applied to the skin prior to incision, while the remainder underwent the same surgery without a drape. Culture swabs were taken from the surgical site at 5 points (preskin preparation, after skin preparation, postincision, before subcutaneous closure, prior to dressing application) and sent for culture and colony counts. Mixed-effects logistic regressions were used to estimate effects of time and drape application on contamination rate. RESULTS: At the conclusion of surgery, 12.0% of incisions with adhesive drapes and 27.4% without adhesive drapes were positive for bacterial colonization. When controlling for preoperative colonization and other factors, patients without adhesive drapes were significantly more likely to have bacteria present at the time of skin closure, and at all time points when swab cultures were taken. CONCLUSION: It appears that the iodophor-impregnated adhesive draping significantly reduces bacterial colonization of the incision. Bacterial count at the skin was extremely high in some patients in whom adhesive drapes were not used, raising the possibility that a subsequent surgical site infection or periprosthetic joint infection could arise had an implant been utilized.

Infection Following Total Joint Arthroplasty Is the Main Cause of Litigation: Data From One Metropolitan Area.

BACKGROUND: A prior survey of members of the American Association of Hip and Knee Surgeons revealed that 78% of responding surgeons were named as a defendant in at least 1 lawsuit, and 69% of these lawsuits were dismissed or settled out of court. The most common sources of litigation were nerve injury, limb-length discrepancy, and infection. This study examined common reasons for lawsuits after total joint arthroplasty (TJA) in a single metropolitan area. METHODS: A retrospective review of lawsuits filed between 2009 and 2015 in a 5-county metropolitan area was performed, including 30 hospitals and 113 TJA surgeons. Complaints underwent a manual review to determine the number of lawsuits and the specific allegations filed against each surgeon. RESULTS: Thirty-one (27.4%) surgeons were named as a defendant in at least 1 lawsuit. Eighty-three total lawsuits were filed during the period, 50 of which were dismissed or settled outside of court. Top reasons for lawsuits were, in descending order, infection, nerve injury, chronic pain, vascular injury, periprosthetic fracture, retention of foreign body, dislocation, limb-length discrepancy, venous thromboembolism, loosening, compartment syndrome, and other medical complaints. CONCLUSION: Infection appears to be the basis of most lawsuits after TJA. Surgeons should be aware of the potential for a lawsuit for complications and should strive to better communicate with patients regarding preoperative informed consent and disclosure after adverse events. Surgeons should minimize performing surgery in patients at high risk of complications, such as patients with a higher likelihood of developing postoperative infection or patients on chronic pain medications.

Increased Complications for Schizophrenia and Bipolar Disorder Patients Undergoing Total Joint Arthroplasty.

BACKGROUND: Although it has been shown that anxiety and depression are associated with increased complications after total joint arthroplasty (TJA), the outcomes of TJA in patients with a history of psychosis are unknown. This study evaluated the influence of bipolar and schizophrenic disorders on complications after TJA, particularly aseptic and septic revisions. METHODS: A retrospective review of 156 TJAs (125 primaries and 31 revisions) was performed at a single institution from 2000 to 2015. Bipolar and schizophrenic patients were identified based on International Classification of Diseases, Ninth Revision codes or by those actively taking anti-psychotic medications, followed by manual chart review to confirm diagnoses. The psychosis patient cohort was matched 3:1 for a variety of factors. Revisions and readmissions were evaluated. Survivorship curves were generated. RESULTS: Patients with schizophrenia or bipolar disorder had an increased odds of developing peri-prosthetic joint infection at 90 days (odds ratio [OR] 3.34, P = .049), 2 years (OR 3.94, P = .004), and at any time point (OR 4.32, P = .002). Psychosis patients had increased odds of aseptic and mechanical revisions at all endpoints, particularly from dislocation. Psychosis patients had a higher number of post-operative emergency department visits (P < .001), and were more likely to be discharged to a rehabilitation facility (P < .001). CONCLUSIONS: Patients with bipolar affective disorder or schizophrenia may have multiple barriers to self-care after TJA, and are at an increased risk for undergoing revision TJA for prosthetic joint infection and mechanical causes. Increased pre-operative education and screening of this patient population may be necessary prior to performing TJA.