National Inpatient Datasets May No Longer Be Appropriate for Overall Total Hip and Knee Arthroplasties Projections after Removal from Inpatient-Only Lists.

It is unknown if the National Inpatient Sample (NIS) remains suitable to conduct projections for total knee arthroplasty (TKA) and total hip arthroplasty (THA), after their removal from "inpatient-only lists" in 2018 and 2020, respectively. We aimed to: (1) quantify primary THA and TKA volume from 2008 to 2018; (2) project estimates of future volume of THA and TKA until 2050; and (3) compare projections based on NIS data from 2008 to 2018 and 2008 to 2017, respectively. We identified all primary THA and TKA performed from 2008 to 2018 from the NIS. The projected volumes of THA and TKA were modeled using negative binomial regression models while incorporating log-transformed population data from the Centers for Disease Control and Prevention. Annual volume increased by 26% for THA and 11% for TKA (2008/2018: THA: 360,891/465,559; TKA:592,352/657,294). Based on 2008 to 2018 data, THA volume is projected to grow 120%, to 1,119,942 THAs by 2050. While, based on 2008 to 2017 data, THA volume is projected to grow 136%, to 1,219,852 THAs by 2050. Based on 2008 to 2018 data, TKA volume is projected to grow 4%, to 794,852 TKAs by 2050. While, based on 2008 to 2017 data, TKA volume is projected to grow 28%, to 1,037,474 TKAs by 2050. Projections based on 2008 to 2017 data estimated up to 240,000 (23%) more annual TKAs by 2050, compared with projections based on 2008 to 2018 data. The largest discrepancy among THA projections was an 8.2% difference (99,000 THAs) for 2050. After 2018 for TKA, and potentially 2020 for THA, projections based on the NIS will have to be interpreted with caution and may only be appropriate to estimate future inpatient volume. Level of evidence is prognostic level II.

The Arthroplasty Surgeon Growth Indicator: A Tool for Monitoring Supply and Demand Trends in the Orthopaedic Surgeon Workforce from 2020 to 2050.

BACKGROUND: Orthopaedic practices in the U.S. face a growing demand for total joint arthroplasties (TJAs), while the orthopaedic workforce size has been stagnant for decades. This study aimed to estimate annual TJA demand and orthopaedic surgeon workforce supply from 2020 to 2050, and to develop an arthroplasty surgeon growth indicator (ASGI), based on the arthroplasty-to-surgeon ratio (ASR), to gauge nationwide supply and demand trends. METHODS: National Inpatient Sample and Association of American Medical Colleges data were reviewed for individuals who underwent primary TJA and for active orthopaedic surgeons (2010 to 2020), respectively. The projected annual TJA volume and number of orthopaedic surgeons were modeled using negative binominal and linear regression, respectively. The ASR is the number of actual (or projected) annual total hip (THA) and/or knee (TKA) arthroplasties divided by the number of actual (or projected) orthopaedic surgeons. ASGI values were calculated using the 2017 ASR values as the reference, with the resulting 2017 ASGI defined as 100. RESULTS: The ASR calculation for 2017 showed an annual caseload per orthopaedic surgeon (n = 19,001) of 24.1 THAs, 41.1 TKAs, and 65.2 TJAs. By 2050, the TJA volume was projected to be 1,219,852 THAs (95% confidence interval [CI]: 464,808 to 3,201,804) and 1,037,474 TKAs (95% CI: 575,589 to 1,870,037). The number of orthopaedic surgeons was projected to decrease by 14% from 2020 to 2050 (18,834 [95% CI: 18,573 to 19,095] to 16,189 [95% CI: 14,724 to 17,655]). This would yield ASRs of 75.4 THAs (95% CI: 31.6 to 181.4), 64.1 TKAs (95% CI: 39.1 to 105.9), and 139.4 TJAs (95% CI: 70.7 to 287.3) by 2050. The TJA ASGI would double from 100 in 2017 to 213.9 (95% CI: 108.4 to 440.7) in 2050. CONCLUSIONS: Based on historical trends in TJA volumes and active orthopaedic surgeons, the average TJA caseload per orthopaedic surgeon may need to double by 2050 to meet projected U.S. demand. Further studies are needed to determine how the workforce can best meet this demand without compromising the quality of care in a value-driven health-care model. However, increasing the number of trained orthopaedic surgeons by 10% every 5 years may be a potential solution.

Should an Age Cutoff Be Considered for Elective Total Knee Arthroplasty Patients? An Analysis of Operative Success Based on Patient-Reported Outcomes.

Total knee arthroplasty (TKA) is increasing in the elderly population; however, some patients, family members, and surgeons raise age-related concerns over expected improvement and risks. This study aimed to (1) evaluate the relationship between age and change in patient-reported outcome measures (PROMs); (2) model how many patients would be denied improvements in PROMs if hypothetical age cutoffs were implemented; and (3) assess length of stay (LOS), readmission, reoperation, and mortality per age group. A prospective cohort of 4,396 primary TKAs (August 2015-August 2018) was analyzed. One-year PROMs were evaluated via Knee injury and Osteoarthritis Outcome Score (KOOS)-pain, -physical function short form (-PS), and -quality of life (-QOL), as well as Veterans Rand-12 (VR-12) physical (-PCS) and mental component (-MCS) scores. Positive predictive values (PPVs) of the number of postoperative "failures" (i.e., unattained minimal clinically important difference in PROMs) relative to number of hypothetically denied "successes" from a theoretical age-group restriction was estimated. KOOS-PS and QOL median score improvements were equivalent among all age groups (p = 0.946 and p = 0.467, respectively). KOOS-pain improvement was equivalent for ≥80 and 60-69-year groups (44.4 [27.8-55.6]). Median VR-12 PCS improvements diminished as age increased (15.9, 14.8, and 13.4 for the 60-69, 70-79, and ≥80 groups, respectively; p = 0.002) while improvement in VR-12 MCS was similar among age groups (p = 0.440). PPV for failure was highest in the ≥80 group, yet remained <34% for all KOOS measures. Overall mortality was highest in the ≥80 group (2.14%, n = 9). LOS >2, non-home discharge, and 90-day readmission were highest in the ≥80 group (8.11% [n = 24], p < 0.001; 33.7% [n = 109], p < 0.001; and 34.4% [n = 111], p = 0.001, respectively). Elderly patients exhibited similar improvement in PROMs to younger counterparts despite higher LOS, non-home discharge, and 90-day readmission. Therefore, special care pathways should be implemented for those age groups.

Do patient-reported outcome measures improve after aseptic revision total hip arthroplasty?

BACKGROUND: The purpose of this study was to determine patient-reported outcome measures (PROMs) changes in: (1) pain, function and global health; and (2) predictors of PROMs in patients undergoing aseptic revision total hip arthroplasty (rTHA) using a multilevel model with patients nested within surgeon. METHODS: A prospective cohort of 216 patients with baseline and 1-year PROMs who underwent aseptic rTHA between January 2016 and December 2017 were analysed. The most common indication for rTHA was aseptic loosening, instability, and implant failure. The PROMs included in this study were HOOS Pain and HOOS Physical Function Short-form (PS), Veterans RAND-12 Physical Component Score (VR-12 PCS), and VR-12 Mental Component Score (MCS). Multivariable linear regression models were constructed for predicting 1-year PROMs. RESULTS: Mean 1-year PROMs improvement for aseptic revisions were 30.4 points for HOOS Pain and 22.1 points for HOOS PS. Predictors of better pain relief were patients with higher baseline pain scores. Predictors of better 1-year function were patients with higher baseline function and patients with a posterolateral hip surgical approach during revision. Although VR-12 PCS scores had an overall improvement, nearly 50% of patients saw no improvement or had worse physical component scores. Only 30.7% of patients reported improvements in VR-12 MCS. CONCLUSIONS: Overall, patients undergoing aseptic rTHA improved in pain and function PROMs at 1 year. Although global health assessment improved overall, nearly half of aseptic rTHA patients reported no change in physical/mental health status. The associations highlighted in this study can help guide the shared decision-making process by setting expectations before aseptic revision THA.

The Learning Curve of Reaching the Planned Limb Alignment in Robotic-Arm-Assisted Total Knee Arthroplasty.

Evidence on the learning curve associated with robotic-arm-assisted total knee arthroplasty (ra-TKA) is scarce and mostly based on operative time. Thus, the objective of this study was to assess a surgeon's learning experience based on accuracy to reach planned limb alignment and its impact on surgical-characteristics, limb-alignment, and perioperative-outcomes. A retrospective chart review was conducted on a consecutive series of 204 primary ra-TKAs (patients), performed by a single surgeon in a single institution (3/7/2018-to-6/18/2019). Cumulative summation control sequential analysis was used for the assessment of the learning curve using accuracy of reaching the planned limb alignment establishing that surgeries had an initial-learning-phase, followed by a second-consolidation-phase. Baseline demographics, operative/tourniquet times, prosthesis type, and limb alignment were compared between these two phases. Length of stay, discharge disposition, complications, reoperation/readmission (90 days), and total morphine equivalents (TMEs) prescribed were compared between phases. Independent sample t-tests, and chi-squared analyses were performed. ra-TKA demonstrated a learning curve of 110 cases for reaching planned limb alignment (p = 0.012). Robotic experience resulted in significantly more proportion of knees in neutral-axis postoperatively (p = 0.035) and significant reduction in TMEs prescribed (p = 0.04). The mean operative and tourniquet time were found to be significantly lower in second-phase versus the first-phase (p for both < 0.0001). ra-TKA has a significant learning curve in clinical practice. A surgeon can reach the planned limb alignment with increased accuracy over time (110-cases). Progressive robotic learning and associated operative time efficiency can lead to significantly lower opioid consumption in patients undergoing TKA.

Technology Review: CT Scan-Guided, 3-Dimensional, Robotic-Arm Assisted Lower Extremity Arthroplasty.

Robotic-arm assisted lower extremity arthroplasty using computed tomography scan (CT)-based 3-dimensional (3D) modeling operative technologies has increasingly become mainstream over the past decade with over 550,000 procedures performed between first use in 2006 and November 2021. Studies have demonstrated multiple advantages with these technologies, such as decreased postoperative pain and subsequent decreased narcotic usage, decreased lengths of stay, less complications, reduced damage to soft tissues, decreased readmissions, as well as economic advantages in the form of meaningful cost savings for payors. The purpose of this report was to clearly and concisely summarize the good-to-high methodology peer-reviewed, published literature regarding CT scan-based, 3-dimensional robotically-assisted unicompartmental knee arthroplasty, total knee arthroplasty, and total hip arthroplasty stratified by: (1) prospective randomized studies; (2) database comparison studies; (3) national registry studies; (4) health utility studies; (5) comparison studies; and (6) basic science studies. A literature search was conducted and, after applying inclusion criteria, each study was graded based on the modified Coleman methodology score ("excellent" 85-100, "good" 70-84, "fair" 55-69, "poor" <54 points). A total of 63 of 63 good-to-excellent methodology score reports were positive for this technology, including 11 that demonstrated decreased pain and/or opioid use when compared to traditional arthroplasty techniques. The summary results of these high-quality, peer-reviewed published studies demonstrated multiple advantages of this CT scan-based robotic-arm assisted platform for lower extremity arthroplasty.

Neuromuscular Electrical Stimulation Use after Total Knee Arthroplasty Improves Early Return to Function: A Randomized Trial.

Neuromuscular electrical stimulation (NMES) has been reported as an effective method for quadriceps strengthening which could attenuate muscle loss in the early total knee arthroplasty (TKA) postoperative recovery period. The purpose of this randomized controlled trial was to test whether postoperative use of NMES on TKA patients results in increased quadriceps strength and ultimately improved functional outcomes. This randomized controlled clinical trial of 66 primary TKA patients was conducted at a large academic medical center. Patients were randomized 2:1 into treatment (NMES use, n = 44) or control arm (no NMES, n = 22). Patients who used the device for an average of 200 minutes/week or more (starting 1 week postoperative and continuing through week 12) were considered compliant. Baseline measurements and outcomes were recorded at 3, 6, and 12 weeks postoperatively, and included quadriceps strength, range of motion (ROM), resting pain, functional timed up and go (TUG), stair climb test, and knee injury and osteoarthritis outcome score (KOOS) and veterans rand 12-item health survey (VR-12) scores. Patients in the treatment arm (NMES use) experienced quadriceps strength gains over baseline at 3, 6, and 12 weeks following surgery, which were statistically significant compared with controls with quadriceps strength losses at 3 (p = 0.050) and 6 weeks (p = 0.015). The TUG improvements for patients treated with NMES showed significant improvements at 6 (p = 0.018) and 12 weeks (p = 0.003) postoperatively. Use of a home-based application-controlled NMES therapy system added to standard of care treatment showed statistically significant improvements in quadriceps strength and TUG following TKA, supporting a quicker return to function.

Greater Prevalence of Mental Health Conditions in Septic Revision Total Knee Arthroplasty: A Call to Action.

The purpose of this study was to compare the prevalence of mental health conditions among patients undergoing (1) primary total knee arthroplasty (pTKA), (2) septic revision total knee arthroplasty (rTKA), and (3) aseptic revision total knee arthroplasty (TKA). The State Inpatient Databases were queried for all TKAs from 2005 to 2014 yielding 563,144 patients. Patients were separated into the following cohorts: primary, septic revision, and aseptic revision. Diagnoses of any mental health condition and the following specific conditions were compared between the three cohorts: schizophrenia/delusion, bipolar disorder, depression/mood disorder, personality disorder, anxiety/somatic/dissociative disorder, eating disorders, attention deficit hyperactivity disorder/conduct/impulse control, alcohol abuse, and drug abuse. Throughout the study period, an increase in the prevalence of mental health conditions was observed in septic and aseptic revision patients. Overall, there was a significantly higher prevalence of mental health conditions in the septic revision cohort (22.7%) compared with the primary (17.8%, p < 0.001) and aseptic revision (20.0%, p < 0.001) cohorts. Specifically, septic revision TKA patients had a higher prevalence of depression (p < 0.001), alcohol abuse (p < 0.001), drug abuse (p < 0.001), schizophrenia (p = 0.0007), and bipolar disorder (p < 0.001), compared with primary TKA patients. Additionally, there was a significantly higher prevalence of depression (p < 0.001), alcohol abuse (p < 0.001), and drug abuse (p < 0.001) among septic revision patients compared with aseptic revision patients. Mental health conditions were significantly higher among septic revision patients. Alcohol and drug abuse were approximately twice as prevalent in septic revision patients compared with primary and aseptic revision patients. These findings should serve as a call to action for mental health support for patients suffering from PJI.

No clinically meaningful difference in 1-year patient-reported outcomes among major approaches for primary total hip arthroplasty.

BACKGROUND: Debate continues around the most effective surgical approach for primary total hip arthroplasty (THA). This study's purpose was to compare 1-year patient-reported outcome measures (PROMs) of patients who underwent direct anterior (DA), transgluteal anterolateral (AL)/direct lateral (DL), and posterolateral (PL) approaches. METHODS: A prospective consecutive series of primary THA for osteoarthritis (n = 2390) were performed at 5 sites within a single institution with standardised care pathways (20 surgeons). Patients were categorised by approach: DA (n = 913; 38%), AL/DL (n = 505; 21%), or PL (n = 972; 41%). Primary outcomes were pain, function, and activity assessed by 1-year postoperative PROMs. Multivariable regression modeling was used to control for differences among the groups. Wald tests were performed to test the significance of select patient factors and simultaneous 95% confidence intervals were constructed. RESULTS: At 1-year postoperative, PROMs were successfully collected from 1842 (77.1%) patients. Approach was a statistically significant factor for 1-year HOOS pain (p = 0.002). Approach was not a significant factor for 1-year HOOS-PS (p = 0.16) or 1-year UCLA activity (p = 0.382). Pairwise comparisons showed no significant difference in 1-year HOOS pain scores between DA and PL approach (p > 0.05). AL/DL approach had lower (worse) pain scores than DA or PL approaches with differences in adjusted median score of 3.47 and 2.43, respectively (p < 0.05). CONCLUSIONS: Patients receiving the AL/DL approach had a small statistical difference in pain scores at 1 year, but no clinically meaningful differences in pain, activity, or function exist at 1-year postoperative.

Temporal Trends in Revision Total Hip and Knee Arthroplasty from 2008 to 2018: Gaps and Opportunities.

BACKGROUND: An overall assessment of how patient demographic characteristics and comorbidities are improving or worsening can allow better understanding of the value of revision total joint arthroplasty (TJA). Therefore, the purpose of this study was to identify patient demographic characteristics and comorbidities trends and episode-of-care outcome trends from 2008 to 2018 in patients undergoing revision TJA. METHODS: The National Surgical Quality Improvement Program database was queried to identify patient demographic characteristics, comorbidities, and episode-of-care outcomes in patients undergoing revision TJA from 2008 to 2018 (n = 45,706). Pairwise t tests and pairwise chi-square tests were performed on consecutive years with Bonferroni correction. Trends were assessed using the 2-tailed Mann-Kendall test of the temporal trend. RESULTS: Among patients undergoing revision TJA, there was no clinically important difference, from 2008 to 2018, in age, body mass index (BMI), percentages with >40 kg/m2 BMI, diabetes (18.8% to 19%), chronic obstructive pulmonary disease (4.1% to 5.4%), congestive heart failure within 30 days (0% to 1%), or acute renal failure (0% to 0.2%). However, modifiable comorbidities including smoking status (14.7% to 12.0%; p = 0.01), hypertension (66% to 26.0%; p = 0.02), anemia (34.5% to 26.3%; p < 0.001), malnutrition (10.4% to 9.3%; p = 0.004), and overall morbidity or mortality probability have improved, with a decrease in the hospital length of stay and 30-day readmission and a significant increase in home discharge (p < 0.001 for all). CONCLUSIONS: Time-difference analysis demonstrated that the overall health status of patients undergoing revision TJA improved from 2008 to 2018. However, formal time-trend analysis demonstrated improvements to a lesser degree. The multidisciplinary effort to improve value-based metrics including patient comorbidity optimization and episode-of-care outcomes for primary TJA has been shown to potentially have an impact on revision TJA. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

NarxCare Scores Greater Than 300 Are Associated with Adverse Outcomes After Primary THA.

BACKGROUND: The association between preoperative prescription drug use (narcotics, sedatives, and stimulants) and complications and/or greater healthcare utilization (length of stay, discharge disposition, readmission, emergency department visits, and reoperation) after total joint arthroplasty has been established but not well quantified. The NarxCare score (NCS) is a weighted scalar measure of overall prescription opioid, sedative, and stimulant use. Higher scores reflect riskier drug-use patterns, which are calculated based on (1) the number of prescribing providers, (2) the number of dispensing pharmacies, (3) milligram equivalence doses, (4) coprescribed potentiating drugs, and (5) overlapping prescription days. The aforementioned factors have not been incorporated into association measures between preoperative prescription drug use and adverse events after THA. In addition, the utility of the NCS as a scalar measure in predicting post-THA complications has not been explored. QUESTIONS/PURPOSES: (1) Is the NarxCare score (NCS) associated with 90-day readmission, reoperation, emergency department visits, length of stay, and discharge disposition after primary THA; and are there NCS thresholds associated with a higher risk for those adverse outcomes if such an association exists? (2) Is there an association between the type of preoperative active drug prescription and the aforementioned outcomes? METHODS: Of 3040 primary unilateral THAs performed between November 2018 and December 2019, 92% (2787) had complete baseline information and were subsequently included. The cohort with missing baseline information (NCS or demographic/racial determinants; 8%) had similar BMI distribution but slightly younger age and a lower Charlson Comorbidity Index (CCI). Outcomes in this retrospective study of a longitudinally maintained institutional database included 90-day readmissions (all-cause, procedure, and nonprocedure-related), reoperations, 90-day emergency department (ED) visits, prolonged length of stay (> 2 days), and discharge disposition (home or nonhome). The association between the NCS category and THA outcomes was analyzed through multivariable regression analyses and a confirmatory propensity score-matched comparison based on age, gender, race, BMI, smoking status, CCI, insurance status, preoperative diagnosis, and surgical approach, which removed significant differences at baseline. A similar regression model was constructed to evaluate the association between the type of preoperative active drug prescription (opioids, sedatives, and stimulants) and adverse outcomes after THA. RESULTS: After controlling for potentially confounding variables like age, gender, race, BMI, smoking status, CCI, insurance status, preoperative diagnosis, and surgical approach, an NCS of 300 to 399 was associated with a higher odds of 90-day all-cause readmission (odds ratio 2.0 [95% confidence interval 1.1 to 3.3]; p = 0.02), procedure-related readmission (OR 3.3 [95% CI 1.4 to 7.9]; p = 0.006), length of stay > 2 days (OR 2.2 [95% CI 1.5 to 3.2]; p < 0.001), and nonhome discharge (OR 2.0 [95% CI 1.3 to 3.1]; p = 0.002). A score of 400 to 499 demonstrated a similar pattern, in addition to a higher odds of 90-day emergency department visits (OR 2.2 [95% CI 1.2 to 3.9]; p = 0.01). After controlling for potentially confounding variables like age, gender, race, BMI, smoking status, CCI, insurance status, preoperative diagnosis, and surgical approach, we found no clinically important association between an active opioid prescription and 90-day all-cause readmission (OR 1.002 [95% CI 1.001 to 1.004]; p = 0.05), procedure-related readmission (OR 1.003 [95% CI 1.001 to 1.006]; p = 0.02), length of stay > 2 days (OR 1.003 [95% CI 1.002 to 1.005]; p < 0.001), or nonhome discharge (OR 1.002 [95% CI 1.001 to 1.003]; p = 0.019); the large size of the database allowed us to find statistical associations, but the effect sizes are so small that the finding is unlikely to be clinically meaningful. A similarly small association that is unlikely to be clinically important was found between active sedative use and 90-day ED visits (OR 1.002 [95% CI 1.001 to 1.004]; p = 0.02). CONCLUSION: Preoperative prescription drug use, as reflected by higher NCSs, has a dose-response association with adverse outcomes after THA. Surgeons may use the preoperative NCS to initiate and guide a patient-centered discussion regarding possible postoperative risks associated with prescription drug-use patterns (sedatives, opioids, or stimulants). An interdisciplinary approach can then be initiated to mitigate unfavorable patterns of prescription drug use and subsequently lower patient NCSs. However, given its nature and its reflection of drug-use patterns rather than patients' current health status, the NCS does not qualify as a basis for surgical denial or ineligibility. LEVEL OF EVIDENCE: Level III, diagnostic study.

Total Knee Arthroplasty among Medicare Beneficiaries with Hemophilia A and B Is Associated with Increased Complications and Higher Costs.

Operations on patients with hemophilia A and B are complex. Studies evaluating postoperative outcomes and costs following total knee arthroplasty (TKA) in patients with hemophilia are limited. A retrospective review of the entire Medicare dataset from 2005 to 2014 was performed. International Classification of Disease 9th revision codes were used to identify patients with hemophilia A and B and they were matched to controls using a 1:1 random matching process based on age, gender, Charlson Comorbidity Index (CCI), and select comorbidity burden. The 90-day preoperative period was evaluated for comorbidities and the 90-day postoperative period was analyzed for outcomes and reimbursements. Logistic regression models were generated to compare outcomes between cases and controls. A total of 4,034 patients with hemophilia were identified as having undergone TKA. About 44.8% were between the ages of 65 and 74 and 62.4% were female. Although the CCI was identical in both cohorts, individual comorbidities not controlled for varied significantly. Medical complications were more frequent among the patients with hemophilia: postoperative bleeding (odds ratio [OR]: 1.7; 95% confidence interval [CI]: 1.2-2.3), deep venous thrombosis (OR: 2.3; 95% CI: 1.8-2.8), pulmonary embolism (OR: 2.9; 95% CI: 2.1-3.9), and blood transfusions (OR: 1.8; 95% CI: 1.6-1.9). Hemophilia was associated with higher odds of periprosthetic infection (1.78 vs. 0.98%, OR: 1.8 95% CI: 1.2-2.7). The 90-day reimbursements were higher for patients with hemophilia (mean: $22,249 vs. $13,017, p < 0.001). Medicare beneficiaries with a diagnosis of hemophilia experience more frequent postoperative complications and incur greater 90-day costs than matched controls following TKA. Surgeons should consider this when optimizing patients for TKA and payors should consider this for risk-adjusting payment models.

The Potential Effects of Imposing a Body Mass Index Threshold on Patient-Reported Outcomes After Total Knee Arthroplasty.

BACKGROUND: Operative eligibility thresholds based on body mass index (BMI) alone may risk restricting access to improved pain control, function, and quality of life. This study evaluated the use of BMI-cutoffs to offering TKA in avoiding: 1) 90-day readmission, 2) one-year mortality, and 3) failure to achieve clinically important one-year PROMS improvement (MCID). METHODS: A total of 4126 primary elective unilateral TKA patients from 2015 to 2018 were prospectively collected. For specific BMI(kg/m2) cutoffs: 30, 35, 40, 45, and 50, the positive predictive value (PPV) for 90-day readmission, one-year mortality, and failure to achieve one-year MCID were calculated. The number of patients denied complication-free postoperative courses per averted adverse outcome/failed improvement was estimated. RESULTS: Rates of 90-day readmission and one-year mortality were similar across BMI categories (P > .05, each). PPVs for preventing 90-day readmission and one-year mortality were low across all models of BMI cutoffs. The highest PPV for 90-day readmission and one-year mortality was detected at cutoffs of 45 (6.4%) and 40 (0.87%), respectively. BMI cutoff of 40 would deny 18 patients 90-day readmission-free, and 194 patients one-year mortality-free postoperative courses for each averted 90-day readmission/one-year mortality. Such cutoff would also deny 11 patients an MCID per avoided failure. Implementing BMI thresholds alone did not influence the rate of improvements in KOOS-PS, KRQOL, or VR-12. CONCLUSION: Utilizing BMI cutoffs as the sole determinants of TKA ineligibility may deny patients complication-free postoperative courses and clinically important improvements. Shared decision-making supported by predictive tools may aid in balancing the potential benefit TKA offers to obese patients with the potentially increased complication risk and cost of care provision.

Estimated glomerular filtration rate is a prognosticator of adverse outcomes after primary total knee arthroplasty among patients with chronic kidney disease and glomerular hyperfiltration.

BACKGROUND: The goals of this study were: (1) to test whether patients with an Estimated glomerular filtration rate (eGFR) that is higher or lower than population-based standards have an increased risk of 30-day mortality, return to the operating room, readmission, non-home discharge, any complication, major complications, and minor complications after primary total knee arthroplasty (TKA); and (2) to find out whether there is a significant non-linear relationship between eGFR and those same variables. METHODS: A total of 168,919 primary TKAs were identified using The National Surgical Quality Improvement Program (NSQIP) database between 1 January 2008 and 31 December 2016. The following outcomes were assessed at 30 days: mortality, return to the operating room, readmission, non-home discharge, any complication, major complications, and minor complications. RESULTS: Multivariate binomial logistical regression found that patients with hyperfiltration had higher rates of readmission (P < 0.03), non-home discharge (P < 0.01), any complication (P < 0.01), major complications (P = 0.03), and minor complications (P < 0.01) compared to reference patients with eGFR in the normal range. Patients with an eGFR less than 60 (stage 3 chronic kidney disease or higher) had increased odds of mortality (P < 0.05), readmission (P < 0.05), any complication (P < 0.01), major complications (P < 0.01), and minor complications (P < 0.01). Spline regression found statistically significant non-linear relationships between eGFR and mortality (P < 0.001), return to the operating room (P = 0.0029), and readmission as well as non-home discharge (P < 0.001). CONCLUSION: Low eGFR and hyperfiltration may be associated with elevated risk of 30-day adverse events. GFR can be used as a risk stratification tool to counseling patients with particular attention paid to those with a GFR < 30 ml/min/1.73 m2.

Developing a personalized outcome prediction tool for knee arthroplasty.

AIMS: The purpose of this study was to develop a personalized outcome prediction tool, to be used with knee arthroplasty patients, that predicts outcomes (lengths of stay (LOS), 90 day readmission, and one-year patient-reported outcome measures (PROMs) on an individual basis and allows for dynamic modifiable risk factors. METHODS: Data were prospectively collected on all patients who underwent total or unicompartmental knee arthroplasty at a between July 2015 and June 2018. Cohort 1 (n = 5,958) was utilized to develop models for LOS and 90 day readmission. Cohort 2 (n = 2,391, surgery date 2015 to 2017) was utilized to develop models for one-year improvements in Knee Injury and Osteoarthritis Outcome Score (KOOS) pain score, KOOS function score, and KOOS quality of life (QOL) score. Model accuracies within the imputed data set were assessed through cross-validation with root mean square errors (RMSEs) and mean absolute errors (MAEs) for the LOS and PROMs models, and the index of prediction accuracy (IPA), and area under the curve (AUC) for the readmission models. Model accuracies in new patient data sets were assessed with AUC. RESULTS: Within the imputed datasets, the LOS (RMSE 1.161) and PROMs models (RMSE 15.775, 11.056, 21.680 for KOOS pain, function, and QOL, respectively) demonstrated good accuracy. For all models, the accuracy of predicting outcomes in a new set of patients were consistent with the cross-validation accuracy overall. Upon validation with a new patient dataset, the LOS and readmission models demonstrated high accuracy (71.5% and 65.0%, respectively). Similarly, the one-year PROMs improvement models demonstrated high accuracy in predicting ten-point improvements in KOOS pain (72.1%), function (72.9%), and QOL (70.8%) scores. CONCLUSION: The data-driven models developed in this study offer scalable predictive tools that can accurately estimate the likelihood of improved pain, function, and quality of life one year after knee arthroplasty as well as LOS and 90 day readmission. Cite this article: Bone Joint J 2020;102-B(9):1183-1193.

Preoperative cut-off values for body mass index deny patients clinically significant improvements in patient-reported outcomes after total hip arthroplasty.

AIMS: Thresholds for operative eligibility based on body mass index (BMI) alone may restrict patient access to the benefits of arthroplasty. The purpose of this study was to evaluate the relationship between BMI and improvements in patient-reported outcome measures (PROMs), and to determine how many patients would have been denied improvements in PROMs if BMI cut-offs were to be implemented. METHODS: A prospective cohort of 3,449 primary total hip arthroplasties (THAs) performed between 2015 and 2018 were analyzed. The following one-year PROMs were evaluated: hip injury and osteoarthritis outcome score (HOOS) pain, HOOS Physical Function Shortform (PS), University of California, Los Angeles (UCLA) activity, Veterans Rand-12 Physical Component Score (VR-12 PCS), and VR-12 Mental Component Score (VR-12 MCS). Positive predictive values for failure to improve and the number of patients denied surgery in order to avoid a failed improvement were calculated for each PROM at different BMI cut-offs. RESULTS: There was a trend to improved outcomes in terms of pain and function improvements with higher BMI. Patients with BMI ≥ 40 kg/m2 had median (Q1, Q3) HOOS pain improvements of 58 points (interquartile range (IQR) 41 to 70) and those with BMI 35 to 40 kg/m2 had median improvements of 55 (IQR 40 to 68). With a BMI cut-off of 30 kg/m2, 21 patients would have been denied a meaningful improvement in HOOS pain score in order to avoid one failed improvement. At a 35 kg/m2 cut-off, 18 patients would be denied improvement, at a 40 kg/m2 cut-off 21 patients would be denied improvement, and at a 45 kg/m2 cut-off 21 patients would be denied improvement. Similar findings were observed for HOOS-PS, UCLA, and VR-12 scores. CONCLUSION: Patients with higher BMIs show greater improvements in PROMs. Using BMI alone to determine eligibility criteria did not improve the rate of clinically meaningful improvements. BMI thresholds prevent patients who may benefit the most from surgery from undergoing THA. Surgeons should consider PROMs improvements in determining eligibility for THA while balancing traditional metrics of preoperative risk stratification. Cite this article: Bone Joint J 2020;102-B(6):683-692.

Does the Timing of the Second Surgery of a Staged Bilateral Total Joint Arthroplasty Affect the Rate of Hospital Adverse Events and Perioperative Outcomes?

BACKGROUND: The optimal timing of the second surgery in primary staged bilateral total hip/knee arthroplasty remains uncertain. Perioperative hospital adverse events represent a significant issue, even "minor events" lead to substantial costs in workup tests, interconsultations, and/or increased hospital length-of-stay (LOS). Therefore, we sought to ascertain whether the timing of the second arthroplasty affects perioperative outcomes and/or rates of adverse events. METHODS: We retrospectively reviewed a consecutive series of 670 primary staged bilateral total hip/knee arthroplasty performed by 2 surgeons (2010-2016) at a single institution. The days between both arthroplasties were calculated for each pair of hips or knees. We evaluated demographics and LOS, discharge disposition, adverse events (ie, nausea, pulmonary embolism), and transfusion rates. The second arthroplasties (n = 335) were set apart in 2 groups based on the time they were done with respect to their corresponding contralateral first arthroplasty using 3 different thresholds: (1) ≤90 vs >90 days, (2) ≤180 vs >180 days, and (3) ≤365 vs >365 days. RESULTS: No significant differences in outcome comparisons were observed using either 90 or 180 days thresholds. However, using the 365 days thresholds, the mean LOS (2.21 vs 1.92 days, P = .015), adverse event (26% vs 15.3%, P = .021), total transfusion (7.4% vs 1.5%, P = .020), and allogeneic transfusion (6.9% vs 1.5%, P = .033) rates were significantly higher in second arthroplasties performed at or less than 1 year apart from the first, respectively. CONCLUSION: Staging the second arthroplasty more than a year apart from the first one seems to offer better LOS and rates of hospital adverse events, transfusions. However, unless patients are willing to wait a year between surgeries, our data also suggest no increased risk in regards to adverse events when proceeding before or after 90/180 days. LEVEL OF EVIDENCE: Level III.

The Utility of Serum d-Dimer for the Diagnosis of Periprosthetic Joint Infection in Revision Total Hip and Knee Arthroplasty.

BACKGROUND: There is scarce and contradicting evidence supporting the use of serum d-dimer for the diagnosis of periprosthetic joint infection in revision total hip (THA) and knee (TKA) arthroplasty. Therefore, the purpose of this study is to test the accuracy of serum d-dimer against the 2013 International Consensus Meeting (ICM) criteria. METHODS: A retrospective review was performed on a consecutive series of 172 revision THA/TKA surgeries performed by 3 fellowship-trained surgeons at a single institution (August 2017 to May 2019) and that had d-dimer performed during their preoperative workup. Of this cohort, 111 (42 THAs/69 TKAs) cases had complete 2013 ICM criteria tests and were included in the final analysis. Septic and aseptic revisions were categorized per 2013 ICM criteria ("gold standard") and compared against serum d-dimer using an established threshold (850 ng/mL). Sensitivity, specificity, likelihood ratios, and positive/negative predictive values were determined. Independent t-tests, Fisher's exact tests, chi-squared tests, and receiver operating characteristic curve analysis were performed. RESULTS: There was no statistically significant difference in baseline demographics between septic and aseptic cases per 2013 ICM criteria. When compared to ICM criteria, d-dimer demonstrated high sensitivity (95.9%) and negative predictive value (90.9%) but low specificity (32.3%), positive predictive value (52.8%), and overall, poor accuracy (61%) to diagnose periprosthetic joint infection. Positive likelihood ratio was 1.42 while negative likelihood ratio was 0.13. The area under the curve (AUC) was 0.742. CONCLUSION: Serum d-dimer has poor accuracy to discriminate between septic and aseptic cases using a described threshold in the setting of revision THA and TKA.

In-Room Ultraviolet Air Filtration Units Reduce Airborne Particles During Total Joint Arthroplasty.

Reducing airborne bioburden in total joint arthroplasty (TJA) is of critical importance. The efficacy of crystalline ultraviolet-C (C-UVC) filtration in reducing bioburden in a dynamic operating room (OR) environment has not been evaluated. We assessed whether C-UVC filtration reduced (i) total particle counts (TPC); (ii) viable particle counts (VPC); and (iii) colony-forming units (CFUs). Fifty primary TJA cases were performed in a positive-pressure OR; 25 cases with the C-UVC unit and 25 cases without. The air was sampled by a particle counter and an impact air sampler to measure particle counts and CFUs, respectively. To compare TPC, VPC, and CFU/m3 between groups, independent t tests and multivariate regression, adjusted for number of OR staff and door openings, were performed. The C-UVC group had significantly lower TPC (2.6 × 106 vs. 4.7 × 106 particles, p = 0.001) and VPC (18,605 vs. 27,516 particles, p = 0.001). There were fewer CFUs in the C-UVC group (10.9 CFU/m3 vs. 13.7 CFU/m3 , p = 0.163). Multivariate analysis identified C-UVC filtration as a significant predictor of decreased TPC (ß = -0.44, p = 0.002) and VPC (ß = -0.47, p = 0.001) after accounting for door openings and number of OR staff. The reduction in CFUs was not significant on multivariate analysis. In this prospective pilot study, a C-UVC air disinfection and recirculation unit led to a significant reduction in both TPC and VPC and a non-significant reduction in CFU. Statement of clinical significance: Further studies are needed to investigate the effects of C-UVC filtration units on surgical-site infection rates. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:431-437, 2020.