Do Patient Engagement Platforms in Total Joint Arthroplasty Improve Patient-Reported Outcomes?

BACKGROUND: Web-based patient engagement portals are increasing in popularity after total hip and knee arthroplasty (THA and TKA). The literature is mixed regarding patient utilization of these modalities and potential clinical benefit. We sought to determine which demographic factors are associated with increased platform participation and to quantify the impact of a web-based patient portal on patient-reported outcome measures (PROMs). METHODS: We performed a retrospective analysis of consecutive primary THA (n = 554) and TKA (n = 485) at a single academic institution with minimum follow-up of 12 months. Patients were divided into those who opted-in and those who opted-out of portal use. Global health and joint-specific PROMs were collected preoperatively and postoperatively. Linear mixed effects modeling, bivariate analysis, and logistic regression were utilized. RESULTS: Of the 1039 included patients, 60.6% (336) THA and 62.7% (304) TKA patients enrolled in the portal. Those who opted-in were younger (P < .001, P < .003), had higher body mass index (P = .024, P = .011), and had a higher household income (P < .001, P < .001) in THA and TKA cohorts, respectively. Portal participation in the TKA but not the THA cohort was associated with significant improvement in physical function (P = .017) and joint-specific function (P = .045). For THA patients who opted-in, increased portal logins were associated with more rapid improvement and higher functional scores (P = .013). CONCLUSION: There is an inherent difference between patients who opt-in to and those who opt-out of web-based portals. Added resources and support provided by portals may translate to improved PROMs for TKA patients but not THA patients.

Does Productivity-Based Physician Compensation Affect Surgical Rates for Elective Arthroplasty Surgery?

BACKGROUND: Surgeon compensation models could potentially influence the utilization of elective procedures. We assessed whether transitioning from salaried to a relative value unit (RVU) productivity-based physician compensation model changed the surgical rate and patient selection in elective total hip and knee arthroplasty (THA and TKA) procedures. METHODS: Our institution transitioned from salaried to RVU productivity-based reimbursement in July 2016. We performed a retrospective analysis on patients undergoing primary THA and TKA from July 2014 to July 2018 before and after the transition (salary period n = 820; RVU period n = 1188). Beta regression was used to determine the reimbursement structure as a predictor of surgery. The surgical rate was defined as the number of primary THA and TKA procedures per reimbursement period divided by all arthroplasty and osteoarthritis outpatient clinic encounters. RESULTS: There was a surgical rate of 15.8% (95% confidence interval [CI] 13.8%-17.8%) THA and 16.7% (95% CI 15.1%-18.1%) TKA procedures during RVU reimbursement compared to 11.1% (95% CI 9.8%-12.8%) THA and 11.7% (95% CI 10.5%-12.8%) TKA procedures during the salaried period (P < .001). The adjusted odds of undergoing a THA or TKA procedure increased in the RVU compared to the salaried model (THA odds ratio 1.48, 95% CI 1.43-1.53; TKA odds ratio 1.50, 95% CI 1.46-1.55; P < .001). There were no significant differences in patient age, gender, race, body mass index, or Charlson Comorbidity Index in salaried vs RVU productivity periods (P > .05 for all covariates). CONCLUSIONS: Productivity-based physician compensation may encourage higher rates of elective arthroplasty procedures without broadening patient selection.

Do Medicare's Patient-Reported Outcome Measures Collection Windows Accurately Reflect Academic Clinical Practice?

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Long-Term Implant Survivorship and Modes of Failure in Simultaneous Concurrent Bilateral Total Knee Arthroplasty.

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.

Preoperative Patient-Reported Outcomes and Clinical Characteristics as Predictors of 90-Day Cost/Utilization and Complications.

BACKGROUND: With the advent of mandatory bundle payments for total joint arthroplasty (TJA), assessing patients' risk for increased 90-day complications and resource utilization is crucial. This study assesses the degree to which preoperative patient-reported outcomes predict 90-day complications, episode costs, and utilization in TJA patients. METHODS: All TJA cases in 2017 at 2 high-volume hospitals were queried. Preoperative HOOS/KOOS JR (Hip Injury and Osteoarthritis Outcome Score/Knee Injury and Osteoarthritis Outcome Score) and Veterans RAND 12-item health survey (VR-12) were administered to patients preoperatively via e-collection platform. For patients enrolled in the Medicare bundle, cost data were extracted from claims. Bivariate and multivariate regression analyses were performed. RESULTS: In total, 2108 patients underwent TJA in 2017; 1182 (56%) were missing patient-reported outcome data and were excluded. The final study population included 926 patients, 199 (21%) of which had available cost data. Patients with high bundle costs tended to be older, suffer from vascular disease and anemia, and have higher Charlson scores (P < .05 for all). These patients also had lower baseline VR-12 Physical Component Summary Score (PCS; 24 vs 30, P ≤ .001) and higher rates of extended length of stay, skilled nursing facility discharge, 90-day complications, and 90-day readmission (P ≤ .04 for all). In multivariate analysis, higher baseline VR-12 PCS was protective against extended length of stay, skilled nursing facility discharge, >75th percentile bundle cost, and 90-day bundle cost exceeding target bundle price (P < .01 for all). Baseline VR-12 Mental Component Summary Score and HOOS/KOOS JR were not predictive of complications or bundle cost. CONCLUSION: Low baseline VR-12 PCS is predictive of high 90-day bundle costs. Baseline HOOS/KOOS JR scores were not predictive of utilization or cost. Neither VR-12 nor HOOS/KOOS JR was predictive of 90-day readmission or complications.

Defining and Optimizing Value in Total Joint Arthroplasty From the Patient, Payer, and Provider Perspectives.

BACKGROUND: 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. METHODS: 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 vs <50th percentile). Multivariate analysis was performed to identify predictors. RESULTS: 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). CONCLUSION: 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.

Ultracongruent Versus Posterior-Stabilized Polyethylene: No Difference in Anterior Knee Pain but Decreased Noise Generation.

BACKGROUND: Noise generation and anterior knee pain can occur after primary total knee arthroplasty (TKA) and may affect patient satisfaction. Polyethylene design in cruciate-sacrificing implants could be a variable influencing these complications. The purpose of this study was to analyze the effect of polyethylene design on noise generation and anterior knee pain. METHODS: We prospectively reviewed a cohort of patients who underwent primary TKA between 2014 and 2022 by a single surgeon using either a posterior-stabilized (PS) or ultracongruent (UC) polyethylene of the same implant design. The primary outcomes were measured through a noise generation questionnaire and the Knee Injury and Osteoarthritis Outcome Score-Patellofemoral score. RESULTS: A total of 409 TKA procedures were included, 153 (37.4%) PS and 256 (62.6%) UC. No difference was noted in the Knee Injury and Osteoarthritis Outcome Score-Patellofemoral score between PS and UC designs (71.7 ± 26 versus 74.2 ± 23.2, P = 0.313). A higher percentage of patients in the PS cohort reported hearing (32.7% versus 22.3%, P = 0.020) or feeling noise (28.8 versus 20.3, P = 0.051) coming from their implant. No notable difference was observed in noise-related satisfaction rates. Independent risk factors of noise generation were age (OR, 0.96; P = 0.006) and PS polyethylene (OR, 1.61; P = 0.043). Noise generation was associated with decreased patient-reported outcome measure scores (P < 0.001). CONCLUSION: While there was no difference in anterior knee pain between PS and UC polyethylene designs, PS inserts exhibit higher rates of noise generation compared with UC. Noise generation had comparable satisfaction but was associated with decreased patient-reported outcome measure scores.

The Effect of Intra-articular Hyaluronic Acid Injections and Payer Coverage on Total Knee Arthroplasty Procedures: Evidence From Large US Claims Database.

Background: There is debate regarding the efficacy of intra-articular (IA) hyaluronic acid (HA) injections for the management of knee osteoarthritis (OA). This study aimed to determine if IA HA utilization and payer coverage of viscosupplementation affected the prevalence of total knee arthroplasty (TKA) procedures and the age of TKA patients. Methods: We performed a retrospective analysis from 2014 to 2020 using a large national commercial claims data set. We analyzed the number of TKA procedures and the age of the patients in states that covered IA HA vs those with limited coverage. Mixed random effects and slopes models were used to identify the impact of the IA HA injections. Results: Of 7,335,301 patients with knee OA, 440,606 (6.0%) received a TKA procedure at an average age of 59 years. The rate of TKA procedures increased by 0.56% per year (95% confidence interval [CI] 0.46-0.66; P < .001). Payer coverage of IA HA injections had no effect on TKA prevalence (P = .926). The age of surgical patients increased yearly by 0.15 years (95% CI 0.12-0.18; P < .001), regardless of IA HA injections (P = .990). After controlling for demographics and comorbidities, patients that received an IA HA injection had a higher probability of receiving a subsequent TKA (odds ratio = 2.83; 95% CI 2.80-2.87; P < .001); this finding was conditional of patients' age at the first diagnosis of knee OA. Conclusions: Additional clinical trials should be employed to identify the role of HA injections in the treatment armamentarium for knee OA.

Online Information and Mentorship: Perspectives From Orthopaedic Surgery Residency Applicants.

INTRODUCTION: Applying to orthopaedic surgery residency is competitive. Online information and mentorship are important tools applicants use to learn about programs and navigate the process. We aimed to identify which resources applicants use and their perspectives on those resources. METHODS: We surveyed all applicants at a single residency program for the 2018 to 2019 application cycle (n = 610) regarding the importance of online resources and mentors during the application process. We defined mentorship as advice from faculty advisors or counselors, orthopaedic residents, medical school alumni, or other medical students. We also assessed their attitudes about the quality and availability of these resources. Applicants were asked to rank resources and complete Likert scales (1 to 5) to indicate the relative utility and quality of options. Descriptive statistics were used to summarize data for comparisons. RESULTS: The response rate was 42% (259 of 610 applicants). Almost 50% of applicants reported that they would have likely applied to fewer programs if they had better information. Applicants used program websites with the highest cumulative frequency (96%), followed by advice from medical school faculty/counselors and advice from orthopaedic residents at home institution (both 82%). The next two most popular online resources were a circulating Google Document (78%) and the Doximity Residency Navigator (73%). On average, the quality of online resources was felt to be poorer than mentorship with advice from orthopaedic residents receiving the highest quality rating (4.16) and being ranked most frequently as a top three resource (122 votes). Mentorship comprised three of the top five highest mean quality ratings and three of the top five cumulative rankings by usefulness. CONCLUSION: Applicants reference online resources frequently, despite valuing mentorship more. If the orthopaedic community fostered better mentorship for applicants, they may not feel compelled to rely on subpar online information. Both online information and mentorship can be improved to create a more effective application experience.

Orthopaedic Surgeon Physiological Indicators of Strain as Measured by a Wearable Fitness Device.

INTRODUCTION: Symptoms of stress, depression, and burnout are prevalent in medicine, adversely affecting physician performance. We investigated real-time measurements of physiological strain in orthopaedic resident and faculty surgeon volunteers and identified potential daily stressors. METHODS: We performed a prospective blinded cohort pilot study in our academic orthopaedic department. Physicians used a wearable fitness device for 12 weeks to objectively measure heart rate variability (HRV), a documented parameter of overall well-being. Baseline burnout levels were assessed using the Maslach Burnout Inventory questionnaire. Daily surveys inquiring on work responsibilities (clinic, operating room [OR], or "other") were correlated with physiological parameters of strain. Descriptive statistics and linear mixed effects modeling were used to evaluate bivariate relationships. RESULTS: Of the 21 participating surgeons, 9 faculty and 12 residents, there was a response rate of 95.2% for the initial burnout survey. Daily surveys were completed for 63.8% (54.9 ± 22.3 days) of the total collection window, and surgeons wore the device for 83.2% of the study (71.6 ± 25.0 days). Residents trended toward lower personal accomplishment and greater psychological detachment on the Maslach Burnout Inventory, with 5 surgeons including 1 faculty surgeon (11.1%) and 4 resident surgeons (33.3%) found to have negatively trending HRV throughout the study period demonstrating higher physiological strain. Time in the OR led to increased next-day HRV (y-intercept = 47.39; B = 4.90; 95% confidence interval, 2.14-7.66; P < 0.001), indicative of lower physiological strain. An increase in device-reported sleep from a surgeon's baseline resulted in a significant increase in next-day HRV (y-intercept = 50.46; B = 0.64; 95% confidence interval, 0.11-1.17; P = 0.02). DISCUSSION: Orthopaedic residents, more than faculty, had physiologic findings suggestive of burnout. Time in the OR and increased sleep improved physiological strain parameters. Real-time biometric measurements can identify those at risk of burnout and in need of well-being interventions. LEVEL OF EVIDENCE: Level III.

Guidelines for Patient-CenteredOpioid Prescribing and Optimal FDA-Compliant Disposal of Excess Pills after Inpatient Operation: Prospective Clinical Trial.

BACKGROUND: To optimize responsible opioid prescribing after inpatient operation, we implemented a clinical trial with the following objectives: prospectively validate patient-centered opioid prescription guidelines and increase the FDA-compliant disposal rate of leftover opioid pills to higher than currently reported rates of 20% to 30%. STUDY DESIGN: We prospectively enrolled 229 patients admitted for 48 hours or longer after elective general, colorectal, urologic, gynecologic, or thoracic operation. At discharge, patients received a prescription for both nonopioid analgesics and opioids based on their opioid usage the day before discharge: if 0 oral morphine milligram equivalents (MME) were used, then five 5-mg oxycodone pill-equivalents were prescribed; if 1 to 29 MME were used, then fifteen 5-mg oxycodone pill-equivalents were prescribed; if 30 or more MME were used, then thirty 5-mg oxycodone pill-equivalents were prescribed. We considered patients' opioid pain medication needs to be satisfied if no opioid refills were obtained. To improve FDA-compliant disposal of leftover pills, we implemented patient education, convenient drop-box, reminder phone call, and questionnaire. RESULTS: Our opioid guideline satisfied 93% (213 of 229) of patients. Satisfaction was significantly higher in lower opioid usage groups (p = 0.001): 99% (99 of 100) in the 0 MME group, 90% (91 of 101) in the 1 to 29 MME group, and 82% (23 of 28) in the 30 or more MME group. Overall, 95% (217 of 229) of patients used nonopioid analgesics. Sixty percent (138 of 229) had leftover pills; 83% (114 of 138) disposed of them using an FDA-compliant method and 51% (58 of 114) used the convenient drop-box. Of 2,604 prescribed pills, only 187 (7%) were kept by patients. CONCLUSIONS: This clinical trial prospectively validated a patient-centered opioid discharge prescription guideline that satisfied 93% of patients. FDA-compliant disposal of excess pills was achieved in 83% of patients with easily actionable interventions.

Screw Fixation Versus Hemiarthroplasty for Nondisplaced Femoral Neck Fractures in the Elderly: A Cost-Effectiveness Analysis.

OBJECTIVE: To evaluate the cost-effectiveness of screw fixation versus hemiarthroplasty for nondisplaced femoral neck fractures in low-demand elderly patients. METHODS: We constructed a Markov decision model using a low-demand, 80-year-old patient as the base case. Costs, health-state utilities, mortality rates, and transition probabilities were obtained from published literature. The simulation model was cycled until all patients were deceased to estimate lifetime costs and quality-adjusted life years (QALYs). The primary outcome was the incremental cost-effectiveness ratio with a willingness-to-pay threshold set at $100,000 per QALY. We performed sensitivity analyses to assess our parameter assumptions. RESULTS: For the base case, hemiarthroplasty was associated with greater quality of life (2.96 QALYs) compared with screw fixation (2.73 QALYs) with lower cost ($23,467 vs. $25,356). Cost per QALY for hemiarthroplasty was $7925 compared with $9303 in screw fixation. Hemiarthroplasty provided better outcomes at lower cost, indicating dominance over screw fixation. CONCLUSIONS: Hemiarthroplasty is a cost-effective option compared with screw fixation for the treatment of nondisplaced femoral neck fractures in the low-demand elderly. Medical comorbidities and other factors that impact perioperative mortality should also be considered in the treatment decision. LEVEL OF EVIDENCE: Economic Level III. See Instructions for Authors for a complete description of levels of evidence.

Acute Tubular Necrosis from Rhabdomyolysis from Leg Compartment Syndrome: A Case Report.

CASE: A 31-year-old male sustained acute compartment syndrome to his left leg after a low-energy fall and required a 4-compartment fasciotomy release. His immediate postoperative course was complicated by acute tubular necrosis (ATN) with creatinine elevated to 4.89 mg/dL from rhabdomyolysis. ATN was managed with aggressive hydration, sodium bicarbonate, and alkaline diuresis, and his creatinine levels improved. CONCLUSIONS: ATN from rhabdomyolysis is a rare complication of compartment syndrome that requires high suspicion and timely treatment to prevent further nephrotoxicity and the resultant increases in mortality. It is imperative for orthopedic surgeons to be aware of this potential complication.

Relationship Between Baseline Patient-reported Outcomes and Demographic, Psychosocial, and Clinical Characteristics: A Retrospective Study.

INTRODUCTION: Alternative payment models in total lower extremity joint replacement (TJR) increasingly emphasize patient-reported outcomes (PROs) to link the latter to value-based payments. It is unclear to what extent demographic, psychosocial, and clinical characteristics are related to PROs measured preoperatively with the commonly used Hip/Knee Osteoarthritis Outcome Scores (HOOS/KOOS) and the Veterans RAND 12-Item Health Survey (VR-12) questionnaires. We aim to identify (1) the preoperative relationship between HOOS/KOOS and VR-12 scores and several demographic, psychosocial, and clinical patient characteristics and (2) the best modifiable factors for optimization, which may result in improved baseline PROs before TJR. METHODS: All TJR cases performed in 2017 at the two highest-volume hospitals within an urban academic health system were queried. Preoperative HOOS/KOOS and VR-12 surveys were administered through an e-collection platform. VR-12 physical and mental component scores (PCS, MCS) were generated. Patient information was extracted from the electronic health record. Bivariate and multivariate regression analyses were performed. Odds ratios (ORs) and 95% confidence intervals were reported. RESULTS: In univariate analysis, patients with HOOS/KOOS, VR-12 PCS, and MCS in the ≤25th percentile group were more likely to have an ASA score of ≥3 compared with those with higher scores. In multivariate analysis, increased and decreased odds of low HOOS/KOOS were associated with a one-unit increase in Charlson Comorbidity Index (OR, 1.16) and VR-12 MCS (OR, 0.97), respectively. Increased odds of low baseline VR-12 PCS and MCS were associated with ASA class ≥3 (OR, 1.65 and 1.40). Decreased odds of a low MCS were associated with an increase in HOOS/KOOS (OR, 0.98) (P ≤ 0.05 for all). CONCLUSION: Of the factors that are associated with low baseline PRO scores, preoperatively addressing mismanaged comorbidities, mental health, and physical function were identified as the best modifiable factors for optimization, which may result in improved baseline PROs before TJR.

Short term patient outcomes after total knee arthroplasty: Does the implant matter?

BACKGROUND: Newer implants for total knee arthroplasty (TKA) often gain market share at higher cost with little patient-reported and long-term clinical data. We compared outcomes after TKA using two different implants: DePuy PFC Sigma and Attune. METHODS: Using a prospective data repository from an academic tertiary medical center, we analyzed 2116 TKAs (1603 Sigma and 513 Attune) from April 2011 through July 2016. Outcomes included length of surgery, length of stay, facility discharge, 90-day reoperation, range of motion (ROM) change, and patient-reported physical function (PCS). RESULTS: There was no difference in length of surgery (Attune -2.87 min, P = 0.143). Implant type was not associated with extended LOS (>3 days) (OR 0.80, P = 0.439). There was no difference in facility discharge (OR 0.65, P = 0.103). Unadjusted 90-day reoperations were 0.3% for Sigma and 1.0% for Attune cohorts (P = 0.158). Sigma implants were associated with more ROM improvement in unadjusted analyses (+2.1 degree improvement P = 0.031). Fifty nine percent of the Sigma cohort and 49% of the Attune cohort achieved the minimal clinically important (MCID) change for PCS improvement, although there was no adjusted difference in achieving MCID (Attune OR 0.84, P = 0.435). There was no adjusted difference in absolute PCS improvement (Attune +0.12 score, P = 0.864). CONCLUSIONS: Our data show no difference in physical function and most outcomes between Sigma and Attune. Attune implants had shorter absolute LOS, but there were no differences in extended LOS.

Effects of the Length of Stay on the Cost of Total Knee and Total Hip Arthroplasty from 2002 to 2013.

BACKGROUND: Utilization of total knee and hip arthroplasty has greatly increased in the past decade in the United States; these are among the most expensive procedures in patients with Medicare. Advances in surgical techniques, anesthesia, and care pathways decrease hospital length of stay. We examined how trends in hospital cost were altered by decreases in length of stay. METHODS: Procedure, demographic, and economic data were collected on 6.4 million admissions for total knee arthroplasty and 2.8 million admissions for total hip arthroplasty from 2002 to 2013 using the National (Nationwide) Inpatient Sample, a component of the Healthcare Cost and Utilization Project. Trends in mean hospital costs and their association with length of stay were estimated using inflation-adjusted, survey-weighted generalized linear regression models, controlling for patient demographic characteristics and comorbidity. RESULTS: From 2002 to 2013, the length of stay decreased from a mean time of 4.06 to 2.97 days for total knee arthroplasty and from 4.06 to 2.75 days for total hip arthroplasty. During the same time period, the mean hospital cost for total knee arthroplasty increased from $14,988 (95% confidence interval [CI], $14,927 to $15,049) in 2002 to $22,837 (95% CI, $22,765 to $22,910) in 2013 (an overall increase of $7,849 or 52.4%). The mean hospital cost for total hip arthroplasty increased from $15,792 (95% CI, $15,706 to $15,878) in 2002 to $23,650 (95% CI, $23,544 to $23,755) in 2013 (an increase of $7,858 or 49.8%). If length of stay were set at the 2002 mean, the growth in cost for total knee arthroplasty would have been 70.8% instead of 52.4% as observed, and the growth in cost for total hip arthroplasty would have been 67.4% instead of 49.8% as observed. CONCLUSIONS: Hospital costs for joint replacement increased from 2002 to 2013, but were attenuated by reducing inpatient length of stay. With demographic characteristics showing an upward trend in the utilization of joint arthroplasty, including a shift toward younger population groups, reduction in length of stay remains an important target for procedure-level cost containment under emerging payment models.