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Patients undergoing total knee arthroplasty (TKA) who have malnutrition have an increased risk of periprosthetic joint infection (PJI). While malnutrition screening and intervention may decrease the risk of PJI, it utilizes healthcare resources. To date, no cost-effectiveness analyses have been done on screening and treatment of malnutrition prior to TKA.A Markov model projecting lifetime costs and quality adjusted life years (QALYs) was built to determine the cost-effectiveness of malnutrition screening and intervention for TKA patients from a societal perspective. Costs, health state utilities, and state transition probabilities were obtained from previously published literature, hospital costs at our institution, and expert opinions. Two important assumptions included that 30% of patients would be malnourished, and that a malnutrition intervention would be 50% effective. The primary outcome of this study was the incremental cost-effectiveness ratio (ICER), with a willingness-to-pay threshold of $100,000 per QALY. One-way and two-way sensitivity analyses were performed to evaluate model parameter assumptions.When utilizing the base case values, universal malnutrition screening and intervention was cost-effective compared to no malnutrition screening or intervention, with an ICER of $6,454 per QALY. Universal screening and intervention remained cost-effective, provided the cost of screening remained below $3,373, the cost of nutritional intervention remained below $12,042, the prevalence of malnutrition among surgical candidates was higher than 2%, and the risk of PJI among patients with malnutrition was greater than 1%.Universal preoperative malnutrition screening and intervention among TKA candidates is cost-effective at parameters encountered in clinical practice. Nutritional optimization programs should be considered to facilitate malnutrition screening and intervention, and future studies should evaluate their efficacy at lowering PJI risk.

Consensus recommendations are lacking regarding appropriate timing of reimplantation following 2-stage resection arthroplasty for prosthetic joint infections (PJIs). We investigated whether the time from resection arthroplasty to reimplantation was associated with treatment outcome at 2 years.Retrospective cohort review was conducted for 101 patients undergoing resection arthroplasty with an antibiotic spacer for PJI at a single tertiary academic referral institution. Time from explantation and spacer placement to reimplantation was categorized into 3 groups:12, 12-18, and18 weeks. Baseline patient and treatment course characteristics across these groups were obtained. Multivariate binary logistic regression was used to characterize association between treatment failure and time to reimplantation, controlling for American Society of Anesthesiologists (ASA) score and prior revision surgery.Time to reimplantation (TTR)18 weeks demonstrated statistically significant increased odds of treatment failure, after controlling for ASA score and prior revision surgery (odds ratio 7.00, confidence interval 2.14-25.42, P = .002). After excluding patients requiring second spacer or Girdlestone prior to replant, this increased odds of failure remained (odds ratio 4.12, confidence interval 1.18-15.37, P = .029). TTR groups were similar with respect to demographics, except for ASA (2.96 for time to reimplantation18 weeks vs 2.55 for time to reimplantation12 weeks; P = .011). Patients with TTR18 weeks were more likely to have an unplanned readmission during the spacer period (48%, 19%, and 6% for time to reimplantation18, 12-18, and 0-12 weeks, respectively; P.002).Although decision regarding TTR is largely patient specific, surgeons should be aware that TTR18 weeks may be associated with higher rates of treatment failure at 2 years.

Background Perioperative antibiotic prophylaxis is used to prevent surgical site infection and periprosthetic joint infection (PJI) after total joint arthroplasty (TJA). Secondary to a national shortage of cefazolin, patients at our institution began receiving a single preoperative prophylactic antibiotic dose for primary TJA and no 24-hour postoperative antibiotic prophylaxis. The purpose of the study was to compare the efficacy of single-dose antibiotic use versus 24-hour dosing of prophylactic antibiotics in the prevention of acute PJI and short-term complications after primary TJA. Methods A retrospective review of 3317 patients undergoing primary TJA performed from January 2015 to December 2019 identified 554 patients who received a single dose of preoperative antibiotic prophylaxis during the antibiotic shortage and 2763 patients who received post-TJA 24-hour antibiotic prophylaxis before the shortage. Patient records were evaluated for acute PJI, superficial infection, 90-day reoperation, and 90-day complications. Results There were no significant differences in patient characteristics between single-dose and 24-hour antibiotic groups. Similarly, there were no significant differences in rates of acute PJI (0.7% vs 0.2%; P = .301), superficial infection (2.4% vs 1.4%; P = .221), 90-day reoperation (2.1% vs 1.1%; P = .155), and 90-day complications (9.9% vs 7.9%; P = .169) between single and 24-hour antibiotic dose. Post hoc power analysis demonstrated adequate sample size, beta = 93%. Conclusion Single-dose prophylactic antibiotics did not lead to an increased risk of acute PJI or short-term complications after TJA. Our study suggests that administration of a single antibiotic dose may be safely considered in patients undergoing routine primary TJA.

Several patient-reported outcome measures (PROMs) exist to measure outcomes after total hip arthroplasty (THA) but can be limited by patient-perceived burden and completion rates. We analyzed whether the modified single assessment numerical evaluation (M-SANE), a one-question PROM, would perform similarly to multiple-question PROMs among patients undergoing primary THA.Patients undergoing THA completed the Patient-Reported Outcomes Measurement Information System-10 (PROMIS-10), the Hip Disability and Osteoarthritis Outcomes Score Junior (HOOS-Jr), and M-SANE questionnaires both preoperatively and postoperatively. The M-SANE assessment asked patients to assess their hip on a scale from 0 to 10, with 10 being the best possible score. Validity of M-SANE compared with other PROMs was determined by Spearman's correlation and floor and ceiling effects. Responsiveness was analyzed using standardized response mean (SRM).One hundred and thirty six patients with at least 1-year follow-up were reviewed. The average M-SANE score improved from 3.3 preoperatively to 7.1 at one year postoperatively. There was moderate to strong correlation at one-year follow-up between the M-SANE and HOOS-Jr (ρ = 0.75, P.001) and PROMIS-10 physical component summary (ρ = 0.63, P.001). Floor and ceiling effects of the M-SANE (floor 2.0%, ceiling 21.3%) were comparable to the HOOS-Jr (floor 0.0%, ceiling 20.8%). The responsiveness of the M-SANE after THA (SRM = 1.06, 95% CI: 0.79-1.33) was comparable to HOOS-Jr (SRM = 1.33, 95% CI: 1.08-1.59) and superior to PROMIS-10 physical component summary (SRM = 0.65, 95% CI: 0.55-0.74).The M-SANE has performed similarly across multiple psychometric properties compared with more burdensome PROMs in assessing longitudinal patient-reported outcomes after THA.

Patient-reported outcome measures (PROMs) are important for tracking outcomes following total knee arthroplasty (TKA) but can be limited by time constraints and patient compliance. We sought to evaluate the utility of the one-question, modified single assessment numerical evaluation (M-SANE) score in TKA patients compared to legacy PROMs.Patients undergoing TKA completed the Patient-Reported Outcomes Measurement Information System-10 (PROMIS-10), the Knee Disability and Osteoarthritis Outcomes Score Junior (KOOS Jr), and M-SANE (modified-SANE) assessments both preoperatively and postoperatively. The M-SANE score asked patients to rate their native or prosthetic knee on a scale from 0 to 10, with 10 being the best function. M-SANE validity was determined by the Spearman's correlation between the collected PROMs and the Bland-Altman plots. PROM responsiveness was assessed using the standardized response mean.In total, 217 patients completed PROMs preoperatively and at 1 year postoperatively. Floor and ceiling effects of the M-SANE were higher than other PROMs but still relatively low (4%-11%). There was a moderate to strong correlation at nearly all time points between the M-SANE and KOOS Jr (ρ = 0.44-0.78, P.001). There was a weak correlation between the M-SANE and PROMIS physical component summary at the preoperative evaluation (ρ = 0.28) but a strong correlation at 1-year follow up (0.65, P.001). The long-term responsiveness of the M-SANE to TKA (standardized response mean [SRM] = 0.98, 95% confidence interval [CI] 0.80-1.17) was comparable to both the KOOS Jr (SRM = 1.19, 95% CI 1.00-1.38) and PROMIS physical component summary (SRM = 0.82, 95% CI 0.74-0.91). Bland-Altman plots demonstrated that the M-SANE and KOOS Jr capture combined knee pain and functionality differently.The M-SANE score was comparable to validated multiple-question PROMs in TKA patients. The demonstrated validity of the M-SANE, as well as its comparable responsiveness to more lengthy PROMs, highlights its use as a one-question PROM for assessment of patient undergoing TKA.

Background COVID-19 has created a void in surgical education. Given social distancing and postponed surgeries, unique educational opportunities have arisen. Attendings from 10 adult reconstruction fellowships led a multi-institution web-based weekly collaborative, the Arthroplasty Consortium (AC), developed to educate trainees through complex arthroplasty case-based discussions. Methods We performed an anonymous survey of AC participants and American Association of Hip and Knee Surgeons (AAHKS) adult reconstruction fellows. Participants were polled with regards to educational tools used before and after COVID-19 and their value. Specifically, participation in the AC, AAHKS FOCAL (Fellows Orthopedic Continued AAHKS Learning) lectures, institutional lectures, industry lectures, textbooks, online videos, journal articles, and webinars was assessed. Results Fifty-seven participants responded with 49 (86%) at the fellow level. There was an increase in the use of web-based learning, including the AC (Not applicable pre, 61% post), AAHKS FOCAL lectures (Not applicable pre, 82% post), industry lectures (53% pre, 86% post), and AAHKS/AAOS webinars (35% pre, 56% post). Usage declined with institutional lectures (89% pre, 80% post), textbooks (68% pre, 49% post), and journal articles (97% pre, 90% post), with minimal change in the use of online surgical videos (84% pre, 82% post). The majority of fellows not involved in the AC would like to see the addition of a multi-institutional case conference added to fellowship education. Of AC participants, the 2 most valuable educational tools were the AC and FOCAL lectures. Conclusion Trainee education has changed post-COVID-19 with a greater focus on web-based learning. Multi-institutional collaborative lectures and case-based discussions have significant perceived value among trainees and should be considered important educational tools post-COVID 19.

Background Under bundled payment models, gainsharing presents an important mechanism to ensure engagement and reward innovation. We hypothesized that metric selection, metric targets, and risk adjustment would impact surgeons’ performance in gainsharing models. Methods Patients undergoing total joint arthroplasty at an urban health system from 2017 to September 2018 were included. Gainsharing metrics included the following: length of stay, % discharge-to-home, 90-day readmission rate, % of patients with episode spend under target price, and % of patients with patient-reported outcomes (PROs) collected. Four scenarios were created to evaluate how metric selection/adjustment impacted surgeons’ performance designation: scenario 1 used “aspirational targets” (>60th percentile), scenario 2 used “acceptable targets” (>50th percentile), scenario 3 risk-adjusted surgeon performance prior to comparing aspirational targets, and scenario 4 included a PRO collection metric. Number of metrics achieved determined performance tier, with higher tiers getting a greater share of the gainsharing pool. Results In total, 2776 patients treated by 12 surgeons met inclusion criteria (mean length of stay 3.0 days, readmission rate 4.0%, discharge-to-home 74%, episode spend under target price 85%, PRO collection 56%). Lowering of metric targets (scenario 1 vs. 2) resulted in a 75% increase in the number of high performers and 98% of the gainsharing pool being eligible for distribution. Risk adjustment (scenario 3) caused 50% of providers to move to higher performance tiers and potential payments to increase by 28%. Adding the PRO metric did not change performance. Conclusion Quality metric/target selection and risk adjustment profoundly impact surgeons’ performance in gainsharing contracts. This impacts how successful these contracts can be in driving innovation and dis-incentivizing the “cherry picking” of patients. Level of evidence Level III.

The traditional goal of the gap-balancing method in total knee arthroplasty is to create equal and symmetric knee laxity throughout the arc of flexion. The purpose of this study was to (1) quantify the laxity in the native and the replaced knee throughout the range of flexion in gap-balancing total knee arthroplasty (TKA) and (2) quantify the precision in achieving a targeted gap profile throughout flexion using a robotic-assisted technique with active ligament tensioning.Robotic-assisted, gap-balancing TKA was performed in 14 cadaver specimens. The proximal tibia was resected, and the native tibiofemoral gaps were measured using a robotic tensioner that dynamically tensioned the soft-tissue envelope throughout the arc of flexion. The femoral implant was then aligned to balance the gaps at 0° and 90° of flexion. The postoperative gaps were then measured during final trialing with the robotic tensioner and compared with the planned gaps.The native gaps increased by 3.4 ± 1.7 mm medially and 3.7 ± 2.1 mm laterally from full extension to 20° of flexion (P.001) and then remained consistent through the remaining arc of flexion. Gap balancing after TKA produced equal gaps at 0° and 90° of flexion, but the gap laxity in midflexion was 2-4 mm greater than at 0° and 90° (P.001). The root mean square error between the planned gaps and actual measured postoperative gaps was 1.6 mm medially and 1.7 mm laterally throughout the range of motion.Aiming for equal gaps at 0° and 90° of flexion produced equal gaps in extension and flexion with larger gaps in midflexion. Consistent soft-tissue balance to a planned gap profile could be achieved by using controlled ligament tensioning in robotic-assisted TKA.

Background This prospective cohort study evaluates the impact of total hip arthroplasty and total knee arthroplasty on patient’s spouses/significant others (SSOs). Methods Patients and SSOs were provided similar outcome metrics (Global Health Patient-Reported Outcomes Measurement Information System, Hip Disability and Osteoarthritis Outcome Score for Joint Replacement, and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement) at preoperative and postoperative visits. Pearson correlation was used to evaluate scores. Results Our sample included 99 patients (58 total hip arthroplasties and 41 total knee arthroplasties). We found strong correlation between patient and SSO mental status scores. We found moderate correlation for some physical function domains. Conclusion SSOs closely share total joint arthroplasty patient’s mental and even some of the physical burden of disease and recovery.

INTRODUCTION: Irrigation and debridement with modular component exchange (IDMCE) can treat prosthetic joint infection (PJI) following total knee arthroplasty (TKA). Compared to two-stage revision, IDMCE is associated with lower morbidity, but may carry higher infection recurrence rates. We aimed to identify prognostic factors associated with successful IDMCE following patients with PJI. METHODS: We identified 99 consecutive patients who underwent IDMCE following TKA PJI at a tertiary academic medical center from November 2009 through January 2016. Examined variables included age, gender, symptom duration, body mass index, Charlson Comorbidity Index, total protein, albumin, hemoglobin A1c, erythrocyte sedimentation rate (ESR), C-reactive protein, white blood cell count, gram stain results, final cultures, and use of long-term antibiotic suppression. Success was defined as no further operation on the ipsilateral knee. We used t-tests and chi-squared analyses to determine whether each preoperative factor was associated with IDMCE reoperation. RESULTS: At mean follow-up of 2.6 years, 64 patients who underwent IDMCE were defined as successful. Thirty-five patients required one or more additional procedures for recurrent infection; of these, 20 patients underwent two-stage revision. Patients with symptom duration of less than two days avoided additional surgery in 88% of cases. Elevated ESR >47mm/hr was the only variable associated with reoperation (P=0.005). There were no associations among the other examined variables. CONCLUSION: Using IDMCE for PJI after TKA required reoperation in 35% of cases. Elevated preoperative ESR laboratory values and duration of symptoms >2 days were associated with re-operation.

Background This study investigates the cost-effectiveness of total hip arthroplasty (THA) in patients 80 years old. Methods A Markov, state-transition model projecting lifetime costs and quality-adjusted life years (QALYs) was constructed to determine cost-effectiveness from a societal perspective. Costs (in 2016 US dollars), health state utilities, and state transition probabilities were obtained from published literature. Primary outcome was incremental cost-effectiveness ratio, with a willingness-to-pay threshold of $100,000/QALY. Sensitivity analyses were performed to evaluate parameter assumptions. Results At our base-case values, THA was cost-effective compared to non-operative treatment with a total lifetime accrued cost of $186,444 vs $182,732, and a higher lifetime accrued utility (5.60 vs 5.09). Cost per QALY for THA was $33,318 vs $35,914 for non-operative management, and the incremental cost-effectiveness ratio was $7307 per QALY. Sensitivity analysis demonstrated THA to be cost-effective with a utility of successful primary THA above 0.67, a peri-operative mortality risk below 0.14, and a risk of primary THA failure below 0.14. Analysis further demonstrated that THA is a cost-effective option below a base-rate mortality threshold of 0.19, corresponding to the average base-rate mortality of a 93-year-old individual. Markov cohort analysis indicated that for patients undergoing THA at age 80 there was an approximate 28% reduction in total lifetime long-term assisted living expenditure compared to non-operatively managed patients with end-stage hip osteoarthritis. Conclusion The results of our model demonstrate that THA is a cost-effective option compared to non-operative management in patients ≥80 years old. This analysis may inform policy regarding THA in elderly patients.

We sought to determine whether several preoperative socioeconomic status (SES) variables meaningfully improve predictive models for primary total knee arthroplasty (TKA) length of stay (LOS), facility discharge, and clinically significant Veterans RAND-12 physical component score (PCS) improvement.We prospectively collected clinical data on 2198 TKAs at a high-volume rural tertiary academic hospital from April 2011 through March 2016. SES variables included race and/or ethnicity, living alone, education, employment, and household income, along with numerous adjusting variables. We determined individual SES predictors and whether the inclusion of all SES variables contributed to each 10-fold cross-validated area under the model's area under the receiver operating characteristic (AUC). We also used 1000-fold bootstrapping methods to determine whether the SES and non-SES models were statistically different from each other.At least 1 SES predicted each outcome. Ethnic minority patients and those with incomes$35,000 predicted longer LOS. Ethnic minority patients, the unemployed, and those living alone predicted facility discharge. Unemployed patients were less likely to achieve PCS improvement. Without the 5 SES variables, the AUC values of the LOS, discharge, and PCS models were 0.74 (95% confidence interval [CI] 0.72-0.77, "acceptable"); 0.86 (CI 0.84-0.87, "excellent"); and 0.80 (CI 0.78-0.82, "excellent"), respectively. Including the 5 SES variables, the 10-fold cross-validated and bootstrapped AUC values were 0.76 (CI 0.74-0.79); 0.87 (CI 0.85-0.88); and 0.81 (0.79-0.83), respectively.We developed validated predictive models for outcomes after TKA. Although inclusion of multiple SES variables provided statistical predictive value in our models, the amount of improvement may not be clinically meaningful.

Treatment of massive acetabular bone loss in revision total hip arthroplasty is complex, and various treatment strategies have been described. We describe a novel technique of using a Trabecular Metal Revision Shell as a buttress augment creating a "double-cup" construct rather than the use of custom triflanges or cup-cage constructs for Paprosky types IIIA and IIIB acetabular defects.We retrospectively reviewed 20 double-cup cases at a mean of 2.4 years follow-up at a single institution between 2005 and 2014. We evaluated postoperative radiographic evidence of acetabular loosening and complication rates, restoration of hip center of rotation, preoperative and postoperative modified Harris Hip Score, and Merle d'Aubigne-Postel pain and walking scores.There were no revisions for acetabular loosening and no cases of aseptic loosening. We observed a 25% dislocation rate, which was the most common complication. Most dislocations occurred within the first year after surgery and most were acetabulum only revisions. Hip center of rotation was restored to an average of 22.5 mm within the interteardrop line. Average Harris Hip Score improved from 28.2 to 68.7 (P.001) and Merle d'Aubigne-Postel pain and walking scores improved from 2.7 to 5.1 and 2.4 to 4, respectively (P.001).The double-cup construct is a reliable option for reconstruction of Paprosky type IIIA and IIIB acetabular defects with no cases of acetabular loosening both clinically and radiographically at a mean of 2 years follow-up. The most common complication was dislocation in the acetabulum-only revisions, and clinical outcome measures were reliably improved in surviving cases.

The Comprehensive Care for Joint Replacement (CJR) mandates collection of patient-reported outcome measures (PROMs) for eligible total hip and total knee arthroplasty (THA and TKA) procedures during specific time periods that may not be attainable within routine academic practice.We performed a retrospective analysis of prospectively collected PROM data from a 2017 cohort of primary THA and TKA patients who completed the Patient-Reported Outcomes Measurement Information System-10 global health survey in preoperative or postoperative time periods. The primary outcome was completion rates of Patient-Reported Outcomes Measurement Information System-10 per the CJR collection periods (90-0 days preoperative and 270-365 days postoperative) compared to an extended postoperative collection period of 270-396 days. Bivariate analysis and logistic regression were used to analyze the association between survey completion rates and patient characteristics.Of the 860 primary THAs and TKAs in 2017, 725 (84.3%) had preoperative surveys completed 90-0 days before surgery. Among the 725 patients, 215 (29.7%) completed postoperative surveys within the CJR timeline of 270-365 days. Completion increased by 120 additional surveys (+16.5%) in the additional postoperative time period of 270-396 days (P.001). No patient or procedural factors significantly correlated with a higher likelihood of postoperative PROM completion (P.05 for all covariates).In an academic clinical practice, completion rates of postoperative PROMs as part of routine clinical practice within the CJR mandated period was low for THA and TKA patients. CJR may consider additional time beyond 365 days to improve PROM completion rates.

Background There is limited evidence describing long-term implant survivorship and modes of failure in simultaneous concurrent bilateral total knee arthroplasty (TKA). Methods We performed a retrospective review of 266 consecutive patients (532 knees) who underwent simultaneous concurrent bilateral TKA. We reviewed medical records for preoperative characteristics, perioperative complications, and revision surgeries. The primary outcome was TKA survivorship. Secondary outcomes included indication and type of revision surgery. We used the Kaplan-Meier method to estimate survivorship and characterize risk of revision up to 20 years post-TKA. Results Our cohort had median follow-up of 9.8 years (interquartile range, 3.9-15.9). Forty-four patients (17%) underwent revision. Revision was more common among younger and male patients. The cumulative incidence of first-time revision per knee (n = 532) was 1.27 per 100 component-years. Implant survival was 99% (confidence interval, 97%-99%) at 5 years, 92% (89%-95%) at 10 years, 83% (77%-87%) at 15 years, and 62% (50%-73%) at 20 years. Five and 10-year survivorship compared favorably to estimates of TKA survivorship in the literature. The cumulative incidence of revision surgery per patient was 1.91 per 100 component-years. Implant survival at 5-, 10-, 15-, and 20-year time points was 96% (CI, 92%-98%), 84% (77%-89%), 71% (62%-79%), and 59% (46%-70%), respectively. Aseptic loosening (40%), polyethylene wear (34%), and infection (11%) were the most common indications for revision. Conclusion Simultaneous concurrent bilateral TKA is associated with a higher risk of reoperation for the patient when both knees are evaluated but similar implant survivorship to the literature when each knee was evaluated in isolation.

The purpose of this study is to define value in bundled total joint arthroplasty (TJA) from the differing perspectives of the patient, payer/employer, and hospital/provider.Demographic, psychosocial, clinical, financial, and patient-reported outcomes (PROs) data from 2017 to 2018 elective TJA cases at a multihospital academic health system were queried. Value was defined as improvement in PROs (preoperatively to 1 year postoperatively) for patients, improvement in PROs per $1000 of bundle cost for payers, and the normalized sum of improvement in PROs and hospital bundle margin for providers. Bivariate analysis was used to compare high value vs low value (50th percentile vs50th percentile). Multivariate analysis was performed to identify predictors.A total of 280 patients had PRO data, of which 71 had Medicare claims data. Diabetes (odds ratio [OR], 0.45; P = .02) predicted low value for patients; female gender (OR, 0.25), hypertension (OR, 0.17), pulmonary disease (OR, 0.12), and skilled nursing facility discharge (OR, 0.17) for payers (P ≤ .03 for all); and pulmonary disease (OR, 0.16) and skilled nursing facility discharge (OR, 0.19) for providers (P ≤ .04 for all).This is the first article to define value in TJA under a bundle payment model from multiple perspectives, providing a foundation for future studies analyzing value-based TJA.

Background Periprosthetic joint infection (PJI) after total knee arthroplasty is challenging to diagnose. Compared with culture-based techniques, next-generation sequencing (NGS) is more sensitive for identifying organisms but is also less specific and more expensive. To date, there has been no study comparing the cost-effectiveness of these two methods to diagnose PJI after total knee arthroplasty. Methods A Markov, state-transition model projecting lifetime costs and quality-adjusted life years (QALYs) was constructed to determine the cost-effectiveness from a societal perspective. The primary outcome was incremental cost-effectiveness ratio, with a willingness-to-pay threshold of $100,000/QALY. Sensitivity analyses were performed to evaluate parameter assumptions. Results At our base case values, culture was not determined to be cost-effective compared to NGS, with an incremental cost-effectiveness ratio of $422,784 per QALY. One-way sensitivity analyses found NGS to be the cost-effective choice above a pretest probability of 45.5% for PJI. In addition, NGS was cost-effective if its sensitivity was greater than 70.0% and its specificity greater than 94.1%. Two-way sensitivity analyses revealed that the pretest probability and test performance parameters (sensitivity and specificity) were the largest factors for identifying whether a particular strategy was cost-effective. Conclusion The results of our model suggest that the cost-effectiveness of NGS to diagnose PJI depends primarily on the pretest probability of PJI and the performance characteristics of the NGS technology. Our results are consistent with the idea that NGS should be reserved for clinical contexts with a high pretest probability of PJI. Further study is required to determine the indications and subgroups for which NGS offers clinical benefit.

Background Unicompartmental knee arthroplasty (UKA) is a treatment option for single-compartment knee osteoarthritis. Robotic assistance may improve survival rates of UKA, but the cost-effectiveness of robot-assisted UKA is unknown. The purpose of this study was to delineate the revision rate, hospital volume, and robotic system costs for which this technology would be cost-effective. Methods We created a Markov decision analysis to evaluate the costs, outcomes, and incremental cost-effectiveness of robot-assisted UKA in 64-year-old patients with end-stage unicompartmental knee osteoarthritis. Results Robot-assisted UKA was more costly than traditional UKA, but offered a slightly better outcome with 0.06 additional quality-adjusted life-years at an incremental cost of $47,180 per quality-adjusted life-years, given a case volume of 100 cases annually. The system was cost-effective when case volume exceeded 94 cases per year, 2-year failure rates were below 1.2%, and total system costs were Conclusion Robot-assisted UKA is cost-effective compared with traditional UKA when annual case volume exceeds 94 cases per year. It is not cost-effective at low-volume or medium-volume arthroplasty centers.

Background Patient-reported outcomes are essential to demonstrate the value of hip and knee arthroplasty, a common target for payment reforms. We compare patient-reported global and condition-specific outcomes after hip and knee arthroplasty based on hospital participation in Medicare’s bundled payment programs. Methods We performed a prospective observational study using the Comparative Effectiveness of Pulmonary Embolism Prevention after Hip and Knee Replacement trial. Differences in patient-reported outcomes through 6 months were compared between bundle and nonbundle hospitals using mixed-effects regression, controlling for baseline patient characteristics. Outcomes were the brief Knee Injury and Osteoarthritis Outcomes Score or the brief Hip Disability and Osteoarthritis Outcomes Score, the Patient-Reported Outcomes Measurement Information System Physical Health Score, and the Numeric Pain Rating Scale, measures of joint function, overall health, and pain, respectively. Results Relative to nonbundled hospitals, arthroplasty patients at bundled hospitals had slightly lower improvement in Knee Injury and Osteoarthritis Outcomes Score (−1.8 point relative difference at 6 months; 95% confidence interval −3.2 to −0.4; P = .011) and Hip Disability and Osteoarthritis Outcomes Score (−2.3 point relative difference at 6 months; 95% confidence interval −4.0 to −0.5; P = .010). However, these effects were small, and the proportions of patients who achieved a minimum clinically important difference were similar. Preoperative to postoperative change in the Patient-Reported Outcomes Measurement Information System Physical Health Score and Numeric Pain Rating Scale demonstrated a similar pattern of slightly worse outcomes at bundled hospitals with similar rates of achieving a minimum clinically important difference. Conclusions Patients receiving care at hospitals participating in Medicare’s bundled payment programs do not have meaningfully worse improvements in patient-reported measures of function, health, or pain after hip or knee arthroplasty.

Background Patients aged 80 and above who suffer from end-stage osteoarthritis may benefit from total knee arthroplasty (TKA), but at high potential risk. Additionally, there is controversy about whether functional improvement in patients above age 80 is similar to younger patients. We compared functional improvement, length of stay (LOS), and facility discharge rates after TKA between this cohort and patients less than 80 years of age. Methods We completed a retrospective cohort study comparing TKA patients aged 80 and above with all patients younger than 80. We utilized data from a prospectively collected institutional repository of 2308 TKAs performed from April 2011 through July 2016 at an academic medical center in the United States. We performed multivariable logistic regression to determine the association between age group and clinically significant improvement in the Patient-Reported Outcome Measurement Information System (PROMIS)-10 physical component summary (PCS) score. Secondary outcomes included the magnitude of PCS change, LOS, and facility discharge. Results There were 175 (7.6%) TKAs in patients older than 80 years compared with 2133 TKAs in patients younger than 80. Patients over 80 had similar adjusted odds of achieving clinically significant PCS improvement following TKA (P = .366), and there was no statistical difference in adjusted postoperative PCS improvement between the 2 age groups. Age 80 and above was associated with a longer adjusted LOS and demonstrated increased odds of facility discharge (odds ratio 4.11, P Conclusion Following TKA, patients older than 80 years demonstrate similar adjusted functional improvement in comparison to younger patients. However, older patients did require substantially more resources as they remained in the hospital longer and were discharged to rehabilitation more often.

Background Total knee and hip arthroplasties can be associated with substantial blood loss, affecting morbidity and even mortality. Two pharmacological antifibrinolytics, e-aminocaproic acid (EACA) and tranexamic acid (TXA) have been used to minimize perioperative blood loss, but both have associated morbidity. Given the added cost of these medications and the risks associated with then, a cost-effectiveness analysis was undertaken to ascertain the best strategy. Methods A cost-effectiveness model was constructed using the payoffs of cost (in United States dollars) and effectiveness (quality-adjusted life expectancy, in days). The medical literature was used to ascertain various complications, their probabilities, utility values, and direct medical costs associated with various health states. A time horizon of 10 years and a willingness to pay threshold of $100,000 was used. Results The total cost and effectiveness (quality-adjusted life expectancy, in days) was $459.77, $951.22, and $1174.87 and 3411.19, 3248.02, and 3342.69 for TXA, no pharmacologic hemostatic agent, and EACA, respectively. Because TXA is less expensive and more effective than the competing alternatives, it was the favored strategy. One-way sensitivity analyses for probability of transfusion and myocardial infarction for all 3 strategies revealed that TXA remains the dominant strategy across all clinically plausible values. Conclusion TXA, when compared with no pharmacologic hemostatic agent and with EACA, is the most cost-effective strategy to minimize intraoperative blood loss in hip and knee total joint arthroplasties. These findings are robust to sensitivity analyses using clinically plausible probabilities.