Lessons Learned From the Comprehensive Care for Joint Replacement Model at an Academic Tertiary Center: The Good, the Bad, and the Ugly.

BACKGROUND: Our institution participated in the Comprehensive Care for Joint Replacement (CJR) model from 2016 to 2020. Here we review lessons learned from a total joint arthroplasty (TJA) care redesign at a tertiary academic center amid changing: (1) CJR rules; (2) inpatient only rules; and (3) outpatient trends. METHODS: Quality, financial, and patient demographic data from the years prior to and during participation in CJR were obtained from institutional and Medicare reconciled CJR performance data. RESULTS: Despite an increase in true outpatients and new challenges that arose from changing inpatient-only rules, there was significant improvement in quality metrics: decreased length of stay (3.48-1.52 days, P < .001), increased home discharge rate (70.2-85.5%, P < .001), decreased readmission rate (17.7%-5.1%, P < .001), decreased complication rate (6.5%-2.0%, P < .001), and the Centers for Medicare and Medicaid Services (CMS) Composite Quality Score increased from 4.4 to 17.6. Over the five year period, CMS saved an estimated $8.3 million on 1,486 CJR cases, $7.5 million on 1,351 non-CJR cases, and $600,000 from the voluntary classification of 371 short-stay inpatients as outpatient-a total savings of $16.4 million. Despite major physician time and effort leading to marked improvements in efficiency, quality, and large cost savings for CMS, CJR participation resulted in a net penalty of $304,456 to our institution, leading to zero physician gainsharing opportunities. CONCLUSION: The benefits of CJR were tempered by malalignment of incentives among payer, hospital, and physician as well as a lack of transparency. Future payment models should be refined based on the successes and challenges of CJR.

A Physician-led Care Redesign Blunts Predictors of Length of Stay after Total Hip and Knee Arthroplasty.

We questioned to what extent traditional predictors of care team burden (via increased length of stay [LOS] after total joint arthroplasty [TJA]) were able to be mitigated through alteration of the care pathway. The impact on LOS of traditional patient risk factors, as well as encounter variables, were analyzed for a consecutive set of patients undergoing surgery before and after a physician-initiated arthroplasty care pathway redesign. We analyzed the impact of these variables on LOS, discharge disposition, and 90-day readmission; separate analyses were performed pre- and post-redesign for LOS. Several patient factors (Risk Assessment and Prediction Tool, body mass index, age, insurance type, smoking) predicted longer LOS in the pre-redesign cohort; post-redesign, only ambulation on the day of surgery and anticoagulation type were predictive. The redesign also lessened the aggregate impact of the patient-specific risk factors, resulting in reduced variation in LOS. Physician leadership of care pathways can reduce the impact of factors that have portended longer LOS, thereby reducing variability in LOS and costs for disparate patient populations while driving improvements in value-based care indices. (Journal of Surgical Orthopaedic Advances 32(2):097-101, 2023).

A hybrid implementation-effectiveness randomized trial of CYP2D6-guided postoperative pain management.

PURPOSE: Cytochrome P450 2D6 (CYP2D6) genotype-guided opioid prescribing is limited. The purpose of this type 2 hybrid implementation-effectiveness trial was to evaluate the feasibility of clinically implementing CYP2D6-guided postsurgical pain management and determine that such an approach did not worsen pain control. METHODS: Adults undergoing total joint arthroplasty were randomized 2:1 to genotype-guided or usual pain management. For participants in the genotype-guided arm with a CYP2D6 poor (PM), intermediate (IM), or ultrarapid (UM) metabolizer phenotype, recommendations were to avoid hydrocodone, tramadol, codeine, and oxycodone. The primary endpoints were feasibility metrics and opioid use; pain intensity was a secondary endpoint. Effectiveness outcomes were collected 2 weeks postsurgery. RESULTS: Of 282 patients approached, 260 (92%) agreed to participate. In the genotype-guided arm, 20% had a high-risk (IM/PM/UM) phenotype, of whom 72% received an alternative opioid versus 0% of usual care participants (p < 0.001). In an exploratory analysis, there was less opioid consumption (200 [104-280] vs. 230 [133-350] morphine milligram equivalents; p = 0.047) and similar pain intensity (2.6 ± 0.8 vs. 2.5 ± 0.7; p = 0.638) in the genotype-guided vs. usual care arm, respectively. CONCLUSION: Implementing CYP2D6 to guide postoperative pain management is feasible and may lead to lower opioid use without compromising pain control.

Patient and Procedural Determinants of Postoperative Pain Trajectories.

BACKGROUND: The primary goal of this study was to evaluate patterns in acute postoperative pain in a mixed surgical patient cohort with the hypothesis that there would be heterogeneity in these patterns. METHODS: This study included 360 patients from a mixed surgical cohort whose pain was measured across postoperative days 1 through 7. Pain was characterized using the Brief Pain Inventory. Primary analysis used group-based trajectory modeling to estimate trajectories/patterns of postoperative pain. Secondary analysis examined associations between sociodemographic, clinical, and behavioral patient factors and pain trajectories. RESULTS: Five distinct postoperative pain trajectories were identified. Many patients (167 of 360, 46%) were in the moderate-to-high pain group, followed by the moderate-to-low (88 of 360, 24%), high (58 of 360, 17%), low (25 of 360, 7%), and decreasing (21 of 360, 6%) pain groups. Lower age (odds ratio, 0.94; 95% CI, 0.91 to 0.99), female sex (odds ratio, 6.5; 95% CI, 1.49 to 15.6), higher anxiety (odds ratio, 1.08; 95% CI, 1.01 to 1.14), and more pain behaviors (odds ratio, 1.10; 95% CI, 1.02 to 1.18) were related to increased likelihood of being in the high pain trajectory in multivariable analysis. Preoperative and intraoperative opioids were not associated with postoperative pain trajectories. Pain trajectory group was, however, associated with postoperative opioid use (P < 0.001), with the high pain group (249.5 oral morphine milligram equivalents) requiring four times more opioids than the low pain group (60.0 oral morphine milligram equivalents). CONCLUSIONS: There are multiple distinct acute postoperative pain intensity trajectories, with 63% of patients reporting stable and sustained high or moderate-to-high pain over the first 7 days after surgery. These postoperative pain trajectories were predominantly defined by patient factors and not surgical factors.

Slow Dynamics of Acute Postoperative Pain Intensity Time Series Determined via Wavelet Analysis Are Associated With the Risk of Severe Postoperative Day 30 Pain.

BACKGROUND: Evidence suggests that increased early postoperative pain (POP) intensities are associated with increased pain in the weeks following surgery. However, it remains unclear which temporal aspects of this early POP relate to later pain experience. In this prospective cohort study, we used wavelet analysis of clinically captured POP intensity data on postoperative days 1 and 2 to characterize slow/fast dynamics of POP intensities and predict pain outcomes on postoperative day 30. METHODS: The study used clinical POP time series from the first 48 hours following surgery from 218 patients to predict their mean POP on postoperative day 30. We first used wavelet analysis to approximate the POP series and to represent the series at different time scales to characterize the early temporal profile of acute POP in the first 2 postoperative days. We then used the wavelet coefficients alongside demographic parameters as inputs to a neural network to predict the risk of severe pain 30 days after surgery. RESULTS: Slow dynamic approximation components, but not fast dynamic detailed components, were linked to pain intensity on postoperative day 30. Despite imbalanced outcome rates, using wavelet decomposition along with a neural network for classification, the model achieved an F score of 0.79 and area under the receiver operating characteristic curve of 0.74 on test-set data for classifying pain intensities on postoperative day 30. The wavelet-based approach outperformed logistic regression (F score of 0.31) and neural network (F score of 0.22) classifiers that were restricted to sociodemographic variables and linear trajectories of pain intensities. CONCLUSIONS: These findings identify latent mechanistic information within the temporal domain of clinically documented acute POP intensity ratings, which are accessible via wavelet analysis, and demonstrate that such temporal patterns inform pain outcomes at postoperative day 30.

The Risk Assessment and Prediction Tool Accurately Predicts Discharge Destination After Revision Hip and Knee Arthroplasty.

BACKGROUND: The Risk Assessment and Prediction Tool (RAPT) was developed and validated to predict discharge disposition after primary total hip and knee arthroplasty (THA/TKA). To date, there are no studies evaluating the applicability and accuracy of RAPT for revision THA/TKA. This study aims to determine the predictive accuracy of the RAPT for revision THA/TKA. METHODS: Prospectively collected data from a single tertiary academic medical center were retrospectively analyzed for patients undergoing revision THA/TKA between January 2016 and July 2019. RAPT score was used to predict their postoperative discharge destination and its predictive accuracy was calculated. Patient risk (low, intermediate, and high) for postoperative inpatient rehabilitation facilities or skilled nursing facilities were determined based on the predictive accuracy of each RAPT score. Other factors evaluated included patient-reported discharge expectation, body mass index, and American Society of Anesthesiologists scores. RESULTS: A total of 716 consecutive revision THA/TKA episodes were analyzed. Overall, predictive accuracy of RAPT for discharge disposition was 83%. RAPT scores <3 and >8 were deemed high and low risk of discharge to a post-acute care facility, respectively. RAPT scores of 4 to 7 were still accurate 65%-71% of the time and were deemed to be intermediate-risk. RAPT score and patient-reported discharge expectation had the strongest correlation with actual discharge disposition. CONCLUSION: The RAPT has high predictive accuracy for discharge planning in revision THA/TKA patients. Patient-expected discharge destination is a powerful modulator of the RAPT score and we suggest that it be taken into consideration for preoperative discharge planning.

Revision Arthroplasty Does Not Require More Opioids Than Primaries: A Review of Prescribing Practices After Implementation of a Structured Perioperative Pain Management Strategy.

BACKGROUND: There is a growing body of literature on opioid mitigation strategies following total joint arthroplasty. However, these have almost exclusively been studied in populations undergoing primary procedures, with revision arthroplasty historically thought to be more resistant due to procedural variability and complexity. We report on opioid utilization for revision arthroplasty following implementation of a structured, standardized opioid reduction strategy. METHODS: Beginning January 2015, a comprehensive multidisciplinary pain protocol was developed and applied universally to all patients undergoing hip and knee arthroplasty, including revisions, without exclusion. We performed a retrospective review of opioid prescription trends for the revision arthroplasty subgroup between January 2014 and July 2018, with the first year serving as a baseline for comparison. Inpatient and outpatient opioid prescription data, inpatient satisfaction scores, and quality metrics were also reviewed. RESULTS: We identified 1273 revision arthroplasty cases in the study period. There was a significant reduction in average oral morphine equivalents utilized per procedure when comparing preintervention and postimplementation values. Overall, inpatient prescriptions decreased 24.1% and outpatient utilization decreased 62.4% over the study period. Significant reductions were seen in both the total hip (60.6%) and total knee (64.0%) subgroups. Although revision arthroplasty patients were prescribed 32.5% more oral morphine equivalents at baseline, at year 5 there was no significant difference in outpatient prescriptions between primary and revision subgroups. CONCLUSION: At our institution, a standardized opioid reduction strategy has resulted in marked reduction in opioid prescriptions for revision arthroplasty patients in line with generally successful reductions for primary arthroplasty. More importantly, with this approach, revision arthroplasty patients required no more outpatient opioids than their primary counterparts. LEVEL OF EVIDENCE: Level III, Retrospective cohort study.

The Effect of the COVID-19 Pandemic on Electively Scheduled Hip and Knee Arthroplasty Patients in the United States.

BACKGROUND: In response to the COVID-19 pandemic, hospitals in the United States were recommended to stop performing elective procedures. This stoppage has led to the cancellation of a large number of hip and knee arthroplasties. The effect of this on patients' physical mental and economic health is unknown. METHODS: A survey was developed by the AAHKS Research Committee to assess pain, anxiety, physical function, and economic ability of patients to undergo a delayed operation. Six institutions conducted the survey to 360 patients who had to have elective hip and knee arthroplasty cancelled between March and July of 2020. RESULTS: Patients were most anxious about the uncertainty of when their operation could be rescheduled. Although 85% of patients understood and agreed with the public health measures to curb infections, almost 90% of patients plan to reschedule as soon as possible. Age and geographic region of the patients affected their anxiety. Younger patients were more likely to have financial concerns and concerns about job security. Patients in the Northeast were more concerned about catching COVID-19 during a future hospitalization. CONCLUSIONS: Patients suffering from the pain of hip and knee arthritis continue to struggle with pain from their end-stage disease. They have anxiety about the COVID-19 pandemic. Few patients feel they will be limited financially and 90% want to have surgery as soon as possible. Age and physical location of the patients affect their causes for anxiety around their future surgery.

Clinical Evaluation of Alpha Defensin Test Following Staged Treatment of Prosthetic Joint Infections.

BACKGROUND: Diagnosing persistent infection following staged treatment of prosthetic joint infection (PJI) is challenging. The alpha defensin (AD) test has been shown to be an accurate diagnostic test for the primary diagnosis PJI but has limited evaluation for use following a staged treatment of PJI. The goal of this study was to evaluate the diagnostic accuracy of AD testing following staged treatment of PJI before reimplantation surgery and to determine if negative AD test predicted success following reimplantation using Delphi Criteria at time of last follow-up. METHODS: Patients who underwent AD testing prior to reimplantation after staged treatment of PJI (n = 52) were reviewed. Preoperative data (AD result, synovial fluid [SF], C-reactive protein level [mg/L], SF culture, SF white blood cell count, % of polymorphonuclear lymphocytes, serum C-reactive protein/erythrocyte sedimentation rate) and intraoperative data (purulence and tissue culture) were reviewed and used to classify patients using 2018 Musculoskeletal Infectious Disease Society criteria for infection, which was then used as a gold standard test to calculate diagnostic accuracy. Chart review was used to determine if patients who underwent reimplantation surgery would go on to treatment failure as defined by Delphi Criteria. RESULTS: The sensitivity and specificity of AD test result as compared with Musculoskeletal Infectious Disease Society criteria in diagnosing PJI was calculated to be 71% and 97.78%. Positive predictive value was calculated to be 83.3%, and negative predictive value was calculated to be 95.65%. Patients who underwent reimplantation (46/52 patients) all had negative AD test results, and 9/46 or 19.5% would have treatment failure as defined by the Delphi Criteria with an average follow-up of 588 days. CONCLUSION: AD demonstrates high specificity and negative predictive value, with low sensitivity when utilized after staged treatment of PJI. Further investigation of this and other diagnostic tests following staged treatment of PJI is needed. Additionally, validated criteria used to identify persistent infection following staged treatment of PJI are required.

Bundled Payment "Creep": Institutional Redesign for Primary Arthroplasty Positively Affects Revision Arthroplasty.

BACKGROUND: Revision total joint arthroplasty (TJA) is associated with increased readmissions, complications, and expense compared to primary TJA. Bundled payment methods have been used to improve value of care in primary TJA, but little is known of their impact in revision TJA patients. The purpose of this study is to evaluate the impact of a care redesign for a bundled payment model for primary TJA on quality metrics for revision patients, despite absence of a targeted intervention for revisions. METHODS: We compared quality metrics for all revision TJA patients including readmission rate, use of post-acute care facility after discharge, length of stay, and cost, between the year leading up to the redesign and the 2 years following its implementation. Changes in the primary TJA group over the same time period were also assessed for comparison. RESULTS: Despite a volume increase of 37% over the study period, readmissions declined from 8.9% to 5.8%. Use of post-acute care facilities decreased from 42% to 24%. Length of stay went from 4.84 to 3.92 days. Cost of the hospital episode declined by 5%. CONCLUSION: Our health system experienced a halo effect from our bundled payment-influenced care redesign, with revision TJA patients experiencing notable improvements in several quality metrics, though not as pronounced as in the primary TJA population. These changes benefitted the patients, the health system, and the payers. We attribute these positive changes to an altered institutional mindset, resulting from an invested and aligned care team, with active physician oversight over the care episode.

Arthroplasty Care Redesign Impacts the Predictive Accuracy of the Risk Assessment and Prediction Tool.

BACKGROUND: The Risk Assessment and Prediction Tool (RAPT) is used to predict patient discharge disposition after total joint arthroplasty. Following a comprehensive, multidisciplinary redesign, our institution noticed a trend toward home discharge in patients with RAPT scores that historically predicted discharge to acute care facilities, presenting an opportunity to redefine the predictive ranges for RAPT. METHODS: Retrospectively collected data were analyzed from a single institution in patients undergoing elective primary total joint arthroplasty from January 2016 to April 2017. Predictive accuracy (PA) was calculated for each RAPT score (1-12), RAPT score risk ranges (low, intermediate, and high), as well as overall. Other factors evaluated included patient-reported discharge expectation, body mass index, and American Society of Anesthesiologists scores as related to discharge disposition and the PA of RAPT. RESULTS: Overall PA of RAPT was 88% (n = 1024 patients). Patients were high risk for acute care facility with a RAPT score of 1 to 3 (PA ≥ 83%), intermediate risk 4 to 7 (PA, 52%-79%), and low risk 8 to 12 (PA ≥ 89%). In multivariable analysis, RAPT score and patient-reported discharge expectation had the strongest correlation with actual discharge disposition. CONCLUSION: Our multidisciplinary redesign has impacted the PA of RAPT. The original predictive ranges should be modified to reflect the increasing proportion of patients being discharged home following elective arthroplasty procedures. We have identified patient-expected discharge destination as a powerful modulator of the RAPT score and suggest that it be taken into consideration for discharge planning.

Structural Allograft Supporting a Trabecular Metal Cup Provides Durable Results in Complex Revision Arthroplasty.

BACKGROUND: Revision total hip arthroplasty (THA) is challenging specially in the presence of severe acetabular bone deficiency. We report the use of a highly porous revision shell augmented by structural allograft to provide structural support and coverage to the acetabular component. METHODS: We identified 56 patients (58 hips) undergoing revision THA, where a trabecular metal revision cup was supported by structural allograft. Mean follow-up was 5.4 years (range 2-12 years). Preoperatively acetabular bone defects were classified as Paprosky 2A in 6 hips (10%), 2B in 12 hips (21%), 2C in 12 hips (21%), 3A in 11 hips (19%), and 3B in 17 hips (29%). Structural allograft configuration was classified as type 1 (flying buttress) in 13 hips, type 2 (dome support) in 23 hips, and type 3 (footings) in 17 hips, with 5 hips having combined configurations. RESULTS: All hips showed evidence of union between the allograft and host bone at latest follow-up, 14 hips had partial resorption of the allograft that did not affect cup stability. Three acetabular components demonstrated failure of ingrowth. Survivorship-free from radiographic acetabular loosening as end point was 94% at 5 years. The 5-year survivorship with revision for any reason as end point was 90%. CONCLUSION: Trabecular metal shells combined with structural bone allograft in revision THA demonstrate excellent midterm survival, with 94% of acetabular components obtaining stable union onto host bone at 5 years. Allograft restored bone stock with minimal resorption, and when it occurred did not alter the survivorship of the acetabular component.

Acute delayed infection: increased risk in failed metal on metal total hip arthroplasty.

Adverse local tissue reactions occurring in metal-on-metal total hip arthroplasty (MoM THA) could potentially lead to secondary failure modes such as dislocation or infection. The authors report a series of 124 patients treated with MoM hip arthroplasty between 2006 and 2010 with a minimum follow-up of 3 years. Eight hips presented with acute delayed or late periprosthetic joint infection (PJI) (defined as an infection occurring after 3 months in an otherwise well functioning implant). The rate of infection observed was higher than expected, almost 4 times higher (5.6%) compared to previous historical cohorts from our institution (1.3%). This high risk of infection in patients with DePuy ASR implants requires further study but we theorize that the increased prevalence of infection could be due to a combination of particulate debris, molecular (rather than particulate) effects of Co and Cr ions on soft tissues, and/or products of corrosion that may change the local environment predisposing to infection.

Reversal of the Halo Effect: Prolonged Participation in Comprehensive Care for Joint Replacement Negatively Impacts Revision Metrics.

Background: The downstream regional effect of the Comprehensive Care for Joint Replacement (CJR) program on care pathway-adjacent patients, including revision arthroplasty patients, is poorly understood. Prior studies have demonstrated that care pathways targeting primary total joint arthroplasty may produce a halo effect, impacting more complex patients with parallel care pathways. However, neither the effect of regional referral changes from CJR nor the durability of these positive changes with prolonged bundle participation has been assessed. Methods: Blinded data were pulled from electronic medical records. Primary analyses focused on the effect of CJR participation from 2015 (baseline) to 2020 (final participation year) at a tertiary care safety-net hospital. Patient demographics were evaluated using multivariate analysis of variance and chi-square calculations between procedure types over time. Results: Patients who underwent revision total knee arthroplasty (N = 376) and revision total hip arthroplasty (N = 482) were included. More patients moved through the revision-care pathway over the participation period, with volume increasing by 42% over time. Patients became more medically complex: the Charlson comorbidity index increased from 3.91 to 4.65 (P = .01). The mean length of stay decreased from 5.14 days to 4.50 days (P = .03), but the all-cause complication (8.3%-15.2%; P = .02) and readmission rates (13.6%-16.6%; P = .19) increased over time. Conclusions: Despite care pathway improvements over 5 years of CJR participation, revision patients did not display clear benefits in quality metrics but demonstrated a considerable increase in volume and medical complexity over time. The care of these patients may supersede even thoughtfully implemented care pathways, especially when referral burden increases, as may be prone to happen in regional, financial risk-conferring value-based programs. Understanding the impact of mandatory bundled payment programs like CJR on the care of arthroplasty patients regionally will be essential as value-based programs evolve.

Opioid Utilization After Primary Total Hip and Knee Arthroplasty Following Sequential Implementation of Statewide Legislation.

Background: Following total hip arthroplasty (THA) and total knee arthroplasty (TKA), increased opioid use is associated with poor clinical outcomes. This study investigates implications of Florida legislative mandates on prescribing practices and opioid utilization following primary THA and TKA. Methods: We retrospectively reviewed patients undergoing primary TKA or THA between January 1, 2018, to December 31, 2020 at our academic medical center. Three groups were identified: procedures performed prior to mandates, after seven-day prescription limit, and after mandated electronic prescribing. A multivariate analyses of variance evaluated length of stay, morphine milligram equivalents (MMEs), age, body mass index and number of prescription refills. Chi-square tests compared preoperative opioid use, readmissions, and discharge disposition. Results: There were 198 patients in group one, 238 patients in group two, and 215 patients in group three (N = 651). Prior to any mandates, patients were prescribed 822.3 + 626.7 MMEs. Following a seven-day prescription limit this decreased to 465.0 + 296.0 MMEs (P < .001), which further decreased after mandated electronic prescribing (228.0 + 284.4 MMEs [P < 0.001]). Patients undergoing THA were prescribed less MME than those undergoing TKA. There was a 2.6% 90-day readmission rate, with no pain-related readmissions. Conclusions: Florida legislative mandates for opioid prescription quantities and electronic prescribing have effectively reduced average MMEs prescribed following primary arthroplasty. Despite a shift towards ambulatory surgery, opioid utilization decreased without compromising patient outcomes. These findings underscore the significance of both legislative and surgical practices influencing opioid prescribing habits among orthopaedic surgeons.

Outpatient total hip and knee arthroplasty - Patient expectations versus experience.

Aims & objectives: With modern advancements in surgical techniques and rapid recovery protocols, incidence of outpatient total joint arthroplasty (TJA) is increasing. Previous literature has historically focused on cost, safety, and clinical outcomes, with few studies investigating patient expectations and experiences. The aim of this study was to survey preoperative patient expectations related to outpatient TJA surgery compared with perioperative perceptions and experience. Materials & methods: Prospective study of patients undergoing outpatient total hip or knee arthroplasty at a single Tertiary Academic center. Preoperative and postoperative surveys were administered during routine clinic visits. Results: One hundred and six patients completed preoperative surveys; 79 completed postoperative surveys and were included in the final data analysis. Fifty (63.3 %) patients reported being aware of outpatient TJA prior to undergoing the procedure. There was no difference between preoperative anticipated pain control and postoperative perceived pain control (6.64 vs. 6.88, p = 0.77). Most postoperative patients (N = 56, 70.9 %) rated outpatient surgery as "much better" or "better" than expected. Most postoperative patients (N = 68, 86 %) would opt to have outpatient surgery again. Fifty-two (65.8 %) of postoperative patients believed outpatient surgery sped up their postoperative rehabilitation. Conclusion: For most patients, the outpatient surgical experience met or exceeded expectations. Nearly 90 % of patients would prefer to have outpatient surgery in the future, further supporting the continued migration of elective arthroplasty away from inpatient sites of care.

Comparison of Five-Day vs. Fourteen-Day Incubation of Cultures for Diagnosis of Periprosthetic Joint Infection in Hip Arthroplasty.

Background: Periprosthetic joint infections (PJI) are among the most morbid complications in total hip arthroplasty (THA). The ideal incubation time, however, for intraoperative cultures for PJI diagnosis remains unclear. As such, the aim of this study was to determine if any differences existed in culture-positive rates and organism detection between five-day and fourteen-day cultures. Methods: This retrospective cohort study consisted of THA cases diagnosed with PJI performed between May 2014 and May 2020 at a single tertiary-care institution. Analyses compared five-day and fourteen-day cultures and carried out a pre-specified subgroup analysis by organism and PJI type. Results: A total of 147 surgeries were performed in 101 patients (57.1% females), of which 65% (n = 98) obtained five-day cultures and 34% (n = 49) obtained fourteen-day cultures. The positive culture rate was 67.3% (n = 99) with Staphylococcus aureus being the most common pathogen identified (n = 41 specimens, 41.4%). The positive culture rate was not significantly different between groups (66.3% five-day, 69.4% fourteen-day, p = 0.852). Fourteen-day cultures had a significantly longer time-to-positive culture (5.0 days) than five-day cultures (3.0 days, p < 0.001), a higher rate of fungi (5.6% vs. 0%), and a lower rate of Gram-negatives (4.5% vs. 18.7%, p = 0.016). Conclusions: Fourteen-day cultures did not increase the positivity rate, had higher rates of slow-growth pathogens, and had a longer time-to-positivization than five-day cultures. Prolonged culture holds may provide more thorough organism detection for PJI without increasing the diagnostic culture yield.

The Microbiome of Osteoarthritic Hip and Knee Joints: A Prospective Multicenter Investigation.

BACKGROUND: Recent advances in high-throughput DNA sequencing technologies have made it possible to characterize the microbial profile in anatomical sites previously assumed to be sterile. We used this approach to explore the microbial composition within joints of osteoarthritic patients. METHODS: This prospective multicenter study recruited 113 patients undergoing hip or knee arthroplasty between 2017 and 2019. Demographics and prior intra-articular injections were noted. Matched synovial fluid, tissue, and swab specimens were obtained and shipped to a centralized laboratory for testing. Following DNA extraction, microbial 16S-rRNA sequencing was performed. RESULTS: Comparisons of paired specimens indicated that each was a comparable measure for microbiological sampling of the joint. Swab specimens were modestly different in bacterial composition from synovial fluid and tissue. The 5 most abundant genera were Escherichia, Cutibacterium, Staphylococcus, Acinetobacter, and Pseudomonas. Although sample size varied, the hospital of origin explained a significant portion (18.5%) of the variance in the microbial composition of the joint, and corticosteroid injection within 6 months before arthroplasty was associated with elevated abundance of several lineages. CONCLUSIONS: The findings revealed that prior intra-articular injection and the operative hospital environment may influence the microbial composition of the joint. Furthermore, the most common species observed in this study were not among the most common in previous skin microbiome studies, suggesting that the microbial profiles detected are not likely explained solely by skin contamination. Further research is needed to determine the relationship between the hospital and a "closed" microbiome environment. These findings contribute to establishing the baseline microbial signal and identifying contributing variables in the osteoarthritic joint, which will be valuable as a comparator in the contexts of infection and long-term arthroplasty success. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.