Are orthopedic clinical trials representative? An analysis of race and ethnicity reported in clinical trials between 2007 and 2022 : Running title: representation of clinical trials in orthopedic surgery.

INTRODUCTION: Prior studies investigating the racial and ethnic representation of orthopedic trial participants have found low rates of reporting, but these studies are dated due to the passing of the National Institutes of Health Final Rule in 2017 requiring the reporting of racial and ethnic data among clinical trials. Therefore, we evaluated the representativeness of orthopedic clinical trials before and after the Final Rule. METHODS: A cross-sectional survey of orthopaedic clinical trials registered at ClinicalTrials.gov between October 1, 2007 and May 20, 2023 was conducted. After identifying and screening 23,752 clinical trials, 1564 trials were included in the analysis. Trials started before the implementation of the Final Rule on January 18, 2017 were grouped and compared to trials that began after. Odds ratios (OR) were utilized to identify trial characteristics associated with reporting race/ethnicity data. One-proportion z tests compared the representation of each racial and ethnic category to the 2020 United States Census. RESULTS: In total, 34% (544 of 1564) of orthopedic clinical trials evaluated reported the race of participants, while 28% (438 of 1564) reported ethnicity. Trials registered after the Final Rule were more likely to report racial (OR: 5.15, 95%CI: 3.72-7.13, p < 0.001) and ethnic (OR: 3.23, 95%CI: 2.41-4.33, p < 0.001) representation of participants. Compared with the distribution of race and ethnicity reported by the United States 2020 Census, orthopedic trials had 16.6% more White participants (95% CI 16.4%, 16.8%; p < 0.001), 3.2% fewer Black participants (95%CI 3.1%, 3.3%; p < 0.001), and 5.7% fewer Hispanic/Latino participants (95%CI 5.2%, 6.2%; p < 0.001). Trials with enrollment sizes over 100 participants were also more likely to report race and ethnicity, with odds increasing with increased sample size. CONCLUSIONS: The Final Rule marginally improved the reporting of race and ethnicity in orthopedic clinical trials, and underrepresentation of Black or African American, Multiracial, and Hispanic populations persists. LEVEL OF EVIDENCE: III.

Use of a fluoroscopy-based robotic-assisted total hip arthroplasty system produced greater improvements in patient-reported outcomes at one year compared to manual, fluoroscopic-assisted technique.

INTRODUCTION: The adoption of new technology should be supported by improvements in patient-reported outcomes (PROMs). The purpose of this study was to assess the one-year PROMs of patients who underwent total hip arthroplasty (THA) using a novel, fluoroscopy-based, robotic-assisted (RA-THA) system when compared to a manual, fluoroscopic-assisted technique (mTHA). MATERIALS AND METHODS: A review of 91 consecutive mTHA and 85 consecutive RA-THA via a direct anterior approach was conducted. All cases were performed by the same surgeon at the same institution, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Outcomes included one-year Veterans RAND-12 (VR-12) Physical/Mental, Hip Disability and Osteoarthritis Outcome (HOOS) Pain/Physical Function/Joint Replacement, and University of California Los Angeles (UCLA) Activity scores, as well as the difference between pre-operative and one-year post-operative PROMs. RESULTS: Patients in the RA-THA cohort had lower pre-operative HOOS-JR scores compared to patients in the mTHA cohort (37.0 vs. 43.1; p = 0.031). Cohorts experienced similar one-year post-operative VR-12, HOOS, and UCLA Activity scores. Patients in the RA-THA cohort experienced greater improvements across all pre- and post-operative HOOS scores compared to patients in the mTHA cohort: Pain (+ 54.7 vs. +42.1; p = 0.009), Physical Function (-41.6 vs. -28.7; p = 0.007), and Joint Replacement (+ 46.6 vs. +33.0; p = 0.002). These differences exceeded minimum clinically important difference (MCID). CONCLUSIONS: Both manual and robotic cohorts experienced benefit from THA at one-year post-operative. Importantly, the use of a novel, fluoroscopy-based robotic assistance system for primary THA resulted in greater improvements in PROMs at one-year relative to manual technique.

Use of a novel imageless navigation system reduced fluoroscopy exposure and improved acetabular positioning in anterior approach total hip arthroplasty: a case-control study.

INTRODUCTION: Direct anterior approach (DAA) for total hip arthroplasty (THA) frequently utilizes fluoroscopy. The purpose of this study is to assess the impact of using a novel, imageless THA navigation system on radiation exposure and acetabular cup placement consistency. MATERIALS AND METHODS: This was a retrospective, single-surgeon cohort study of a consecutive group of patients who underwent DAA THA for osteoarthritis. An optic-based imageless navigation system was used to determine intraoperative acetabular inclination and anteversion angles referenced off of a generic coronal and sagittal plane in 71 cases (study group). These were compared with 71 manual cases (control group) for fluoroscopy exposure, operative duration, and acetabular placement variation. Cohorts were similar in their distributions of sex, race, ethnicity, and body mass index. Comparisons between groups were made using independent samples t tests. Alpha error was 0.05. RESULTS: Study patients experienced significantly less fluoroscopy exposure time {3.59 [Standard Deviation (SD) 1.95] vs. 9.15 (SD 5.98) seconds; p < 0.001} and dosage (0.30 [SD 0.23] vs. 0.78 [SD 0.63] mGy; p < 0.001). Study and control patients had similar operative times [82.69 (SD 11.70) vs. 89.54 (SD 14.60) minutes; p = 0.09]. The study group had a significantly lower radiographic variation for inclination and anteversion, based on mean proximity to the centroid of each cohort [3.55 (SD 1.88) vs. 5.39 (SD 3.51); p < 0.001] and also a greater proportion of cases that fell within 1 SD of the mean cohort inclination and anteversion (40.8% vs. 21.1%; p = 0.009). CONCLUSIONS: Use of a novel imageless navigation system for DAA THA significantly reduced fluoroscopic radiation exposure and improved consistency in acetabular cup placement.

COVID-19 disruptions to elective postoperative care did not adversely affect early complications or patient reported outcomes of primary TKA.

INTRODUCTION: Elective orthopedic care, including in-person office visits and physical therapy (PT), was halted on March 16, 2020, at a large, urban hospital at the onset of the local COVID-19 surge. Post-discharge care was provided predominantly through a virtual format. The purpose of this study was to assess the impact of postoperative care disruptions on early total knee arthroplasty (TKA) outcomes, specifically 90-day complications, 120-day rate of manipulation under anesthesia (MUA) and 1-year patient-reported outcome measures (PROMs). MATERIALS AND METHODS: Institutional records were queried to identify 624 patients who underwent primary, unilateral TKA for osteoarthritis and who were discharged home between 1/1/20 and 3/15/20. These patients were compared to 558 controls discharged between 1/1/19 and 3/15/2019. Cohort demographics and in-hospital characteristics were equivalent apart from inpatient morphine milligram equivalent (MME) consumption. Patient-reported access to PT (p < 0.001) and post-discharge care (p < 0.001) were worse among study patients. Study patients were prescribed fewer post-discharge PT sessions (19.8 vs. 23.5; p < 0.001) and utilized telehealth more frequently (p < 0.001). Mann-Whitney U, T, Fisher's Exact, and chi-squared tests were used to compare outcomes. RESULTS: Ninety-day CMS complications were lower among study patients (3.5% vs. 5.9%; p = 0.05). Rates of MUA were similar between groups. Study patients reported similar PROMs and marginally inferior VR-12 mental and LEAS functional outcomes at 1 year. CONCLUSION: Disruptions to elective orthopedic care in March 2020 seemed to have had no major consequences on clinical outcomes for TKA patients. Our findings question the usefulness of pre-pandemic post-discharge protocols, which may over-emphasize in-person visits and PT.

Re-initiation of elective total knee arthroplasty with an adapted pathway during the 2020 COVID-19 pandemic was safe and effective.

INTRODUCTION: In June 2020 when elective total knee arthroplasty (TKA) resumed after the initial COVID-19 surge, we adapted our TKA pathway focusing on a shorter hospitalization, increased home discharge, and use of post-discharge telemedicine and telerehabilitation. The purpose of this study was to evaluate if changes in postoperative care affected early TKA outcomes. MATERIALS AND METHODS: Five hundred and fifty-four patients who underwent elective primary unilateral TKA for primary osteoarthritis between June and August 2020 (study group) were matched 1:1 for age, sex, body mass index, and Charlson comorbidity index with control patients who underwent surgery between August and November 2019. Study patients were discharged 25 h earlier on average compared to controls, more frequently on the same-day or postoperative day-1 (24.9% vs. 16.1%; p = 0.001), and more frequently home (97.3% vs. 83.8%; p < 0.001). Study patients used telemedicine (11.7% vs. 0%; p < 0.001) and telerehabilitation (19.7% vs. 2.5%; p < 0.001) at higher rates than controls. Generalized estimating equations, Mann-Whitney U, and Chi-Square tests were used to compare outcomes between groups including unscheduled office visits, ER visits, readmissions, Center for Medicare and Medicaid Services (CMS) complications, manipulation under anesthesia (MUA), and patient-reported outcomes measures (PROMs). RESULTS: Rates of emergency room visits, readmissions, CMS complications, MUA, and improvements in PROMs were similar between cohorts. Study patients experienced higher rates of unscheduled outpatient visits (9.2% vs. 4.9%; p = 0.004), predominantly due to wound complications. CONCLUSIONS: A protocol implemented during the COVID-19 pandemic that leveraged a shortened hospitalization, higher rates of home discharge, and increased use of telemedicine and telerehabilitation was safe and effective.

Preoperative cannabis use does not increase opioid utilization following primary total hip arthroplasty in a propensity matched analysis.

PURPOSE: The recreational and medical use of cannabis is being legalized worldwide. Its use has been linked to an increased risk of developing opioid use disorders. As opioids continue to be prescribed after total hip arthroplasty (THA), the influence that preoperative cannabis use may have on postoperative opioid consumption remains unknown. The purpose of this study was to assess the relationship between preoperative cannabis use and opioid utilization following primary THA. METHODS: We identified all patients over the age of 18 who underwent unilateral, primary THA for a diagnosis of osteoarthritis at a single institution from February 2019 to April 2021. Our cohort was grouped into current cannabis users (within 6 months of surgery) and those who reported never using cannabis. One hundred and fifty-six current users were propensity score matched 1:6 with 936 never users based on age, sex, BMI, history of chronic pain, smoking status, history of anxiety/depression, ASA classification and type of anesthesia. Outcomes included inpatient and postdischarge opioid use in morphine milligram equivalents. RESULTS: Total inpatient opioid utilization, opioids refilled, and total opioids used within 90 postoperative days were similar between the groups. CONCLUSION: In propensity score matched analyses, preoperative cannabis use was not independently associated with an increase in inpatient or outpatient, 90-days opioid consumption following elective THA.

"Uncontrolled" Hypertension Is Not an Independent Risk Factor for Adverse Short-Term Outcomes Following Total Joint Arthroplasty.

BACKGROUND: Uncontrolled hypertension (HTN) is a risk factor for mortality following elective surgery and poor hemodynamic control during total joint arthroplasty (TJA). However, the relationship between uncontrolled HTN and TJA outcomes remains poorly understood. The purpose of this study is to better define HTN parameters that are predictive of adverse arthroplasty outcomes. METHODS: This is a retrospective cohort analysis on patients who underwent primary TJA for osteoarthritis between 2017 and 2021 at a large orthopedic practice. Uncontrolled HTN was defined as a systolic blood pressure (SBP) > 140 mm Hg, or diastolic blood pressure (DBP) > 90 mm Hg. Spearman's rank correlations were used to evaluate relationships among uncontrolled HTN and operative duration, hemoglobin drop, allogenic transfusions, length of stay, intraoperative/postoperative complications, and readmissions. RESULTS: Four thousand three hundred forty-five patients met the selection criteria, of which 55.1% (N = 2394) presented with uncontrolled HTN. In total, 17.1% (N = 745) and 3.2% (N = 138) of patients had an SBP ≥ 160 and 180 mm Hg, respectively. In addition, 1.9% of patients (N = 84) presented with SBP ≥ 200 mm Hg (N = 13) and/or DBP ≥ 100 mm Hg (N = 71). Eight-four percent (N = 626) of patients who presented with SBP > 160 mm Hg had been preoperatively prescribed HTN control medications. Receiver operator curve analysis demonstrated poor predictive value of blood pressure for all aforementioned outcome variables. CONCLUSION: Our findings suggest that as defined, uncontrolled HTN is not an appropriate individual predictor of TJA outcomes and should not be used as a "hard stop" when determining eligibility for elective surgery. Further research utilizing a larger cohort is needed to define the relationship between HTN and TJA outcomes.

Does Body Mass Index Influence the Outcomes and Survivorship of Modern Cementless Total Knee Arthroplasty?

BACKGROUND: Higher body mass index (BMI) has been associated with higher rates of aseptic loosening following cemented total knee arthroplasty (TKA). However, there is a paucity of evidence on the effect of BMI on the durability of modern cementless TKA. We aimed to assess the association between BMI and clinical outcomes following cementless TKA and to determine if there was a BMI threshold beyond which the risk of revision significantly increased. METHODS: We identified 1,408 cementless TKAs of a modern design from an institutional registry. Patients were classified into BMI categories: normal (n = 136), overweight (n = 476), obese class I (n = 423), II (n = 258), and III (n = 115). The Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and 12-item Short Form Health Survey scores were collected preoperatively and 2 years postoperatively. Survivorship was recorded at minimum 2 years (range, 24 to 88 months). BMI was analyzed as a continuous and categorical variable. RESULTS: The improvement in patient-reported outcomes was similar across the groups. Thirty four knees (2.4%) were revised and 14 (1.0%) were for aseptic failure. Mean time-to-revision was 1.2 ± 1.3 years and did not differ across BMI categories (P = .455). Survivorship free from all-cause and aseptic revision was 97.1% and 99.0% at mean 4 years, respectively. Using Cox regression to control for demographics and bilateral procedures, BMI had no association with all-cause revision (P = .612) or aseptic revision (P = .186). Receiver operating characteristic curve analysis found no relationship between BMI and revision risk (c-statistic = 0.51). CONCLUSION: BMI did not influence functional outcomes and survivorship of modern cementless TKA, possibly due to improved biological fixation at the bone-implant interface. Longer follow-up is necessary to confirm these findings.

Redefining Indications for Modern Cementless Total Knee Arthroplasty: Clinical Outcomes and Survivorship in Patients >75 Years Old.

BACKGROUND: Most studies on cementless total knee arthroplasty (TKA) have excluded patients >75 years due to concerns that older patients have poorer bone mineral density and osteogenic activity. This study compared the midterm outcomes and survivorship of cemented and cementless TKA of the same modern design performed in patients >75 years. METHODS: We identified a consecutive series of 120 primary cementless TKA performed in patients >75 years. Each case was propensity score matched 1:3 with 360 cemented TKA of the same modern design based on age, sex, body mass index, Charlson Comorbidity Index, bilateral procedures, liner type, and year of surgery. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and Short Form-12 (SF-12) were collected preoperatively, at 6 months and 2 years. Implant survivorship was recorded at mean 4.2 years (range, 2.0-7.9). RESULTS: Mean age was 79.0 ± 3.4 years (range, 75-92) in the cemented cohort and 78.9 ± 3.5 (range, 75-91) in the cementless cohort (P = .769). There was no difference in final postoperative scores or improvement in scores at 2 years. The percentage of patients that met the minimal clinically important difference was also similar (KOOS-JR, 68.9% vs 69.2%, P = .955; SF-12 Physical, 71.7% vs 66.7%, P = .299). Seven-year survivorship free from aseptic revision was 99.4% for cemented knees and 100% for cementless knees (log-rank, P = .453). CONCLUSION: Patients over 75 years undergoing cementless or cemented TKA of the same modern design had comparable outcomes and survivorship in the midterm. The theoretical risks of cementless fixation in this age group were not realized in this study.

The Hospital Frailty Risk Score is Not an Accurate Predictor of Treatment Costs for Total Joint Replacement Patients in a Medicare Bundled Payment Population.

BACKGROUND: Medically complex patients require more resources and experience higher costs within total joint arthroplasty (TJA) bundled payment models. While risk adjustment would be beneficial for such patients, no tool currently exists which can reliably identify these patients preoperatively. The purpose of this study is to determine if the Hospital Frailty Risk Score (HFRS) is a valid predictor of high-TJA treatment costs. METHODS: Retrospective analysis was performed on patients who underwent primary TJA between 2015 and 2020 from a single large orthopedic practice. ICD-10 codes from an institutional database were used to calculate HFRS. Cost data including inpatient, postacute, and episode of care (EOC) costs were collected. Charlson comorbidity index, demographics, readmissions, and complications were analyzed. RESULTS: 4936 patients had a calculable HFRS and those with intermediate and high scores experienced more frequent readmissions/complications after TJA, as well as higher EOC costs. However, HFRS did not reliably predict EOC costs, yielding a sensitivity of 49% and specificity of 66%. Multivariate analysis revealed that both patient age and sex are superior individual cost predictors when compared with HFRS. Secondary analyses indicated that HFRS more effectively predicts TJA complications and readmissions but is still nonideal for clinical applications. CONCLUSION: HFRS has poor sensitivity as a predictor of high-EOC costs for TJA patients but has adequate specificity for predicting postoperative readmissions and complications. Further research is needed to develop a scale that can appropriately predict orthopedic cost outcomes.

Use of a fluoroscopy-based robotic-assisted total hip arthroplasty system resulted in greater improvements in hip-specific outcome measures at one-year compared to a CT-based robotic-assisted system.

BACKGROUND: The purpose of this study was to compare one-year patient reported outcome measures between a novel fluoroscopy-based robotic-assisted (FL-RTHA) system and an existing computerised tomography-based robotic assisted (CT-RTHA) system. METHODS: A review of 85 consecutive FL-RTHA and 125 consecutive CT-RTHA was conducted. Outcomes included one-year post-operative Veterans RAND-12 (VR-12) Physical (PCS)/Mental (MCS), Hip Disability and Osteoarthritis Outcome (HOOS) Pain/Physical Function (PS)/Joint replacement, and University of California Los Angeles (UCLA) Activity scores. RESULTS: The FL-RTHA cohort had lower pre-operative VR-12 PCS, HOOS Pain, HOOS-PS, HOOS-JR, and UCLA Activity scores compared with patients in the CT-RTHA cohort. The FL-RTHA cohort reported greater improvements in HOOS-PS scores (-41.54 vs. -36.55; p = 0.028) than the CT-RTHA cohort. Both cohorts experienced similar rates of major post-operative complications, and had similar radiographic outcomes. CONCLUSIONS: Use of the fluoroscopy-based robotic system resulted in greater improvements in HOOS-PS in one-year relative to the CT-based robotic technique.

Body morphometry did not affect the accuracy of a second-generation, miniature imageless navigation system for total hip arthroplasty (THA) using a posterior approach.

Introduction: Some modern imageless navigation platforms for total hip arthroplasty (THA) rely on virtual frontal and sagittal planes determined with the patient in the lateral decubitus position. Body morphometry that changes with gender, body mass index, and other demographic factors may affect accuracy in patient positioning and consequently, navigation accuracy. The objective of this study was to analyze the influence of patient factors on the intraoperative accuracy of a second-generation imageless computer-assisted surgery platform. Methods: 325 consecutive patients undergoing posterior approach, navigated THA arthroplasty for primary osteoarthritis by a single surgeon were retrospectively reviewed. An optic-based imageless navigation system referenced off a generic sagittal and coronal plane was used to determine acetabular inclination and anteversion. Acetabular accuracy was determined by assessing differences between intraoperative values and those obtained from measuring standardized 6-week follow-up radiographs. The effect of age, gender, BMI, race, ethnicity, and laterality on acetabular accuracy was assessed via t-tests, Pearson correlation and ANOVA. Results: Gender had a significant impact on raw inclination accuracy (females and males had an average error of 1.41° and -1.03°, respectively - p < 0.001). There was a weak correlation between acetabular accuracy and patient age and BMI as a continuous variable (both absolute γ < 0.2). No difference was found between acetabular accuracy and BMI groups. Conclusion: This second-generation imageless computer assisted device provided accurate cup positioning regardless of patient's BMI. Gender was the only factor impacting inclination accuracy.

Robotic-assisted total hip arthroplasty utilizing a fluoroscopy-guided system produced similar cup accuracy and precision relative to a computerized tomography-based robotic platform.

Robotic assistance for total hip arthroplasty (THA) has been demonstrated to improve accuracy of acetabular cup placement relative to manual, unassisted technique. The purpose of this investigation was to compare the accuracy and precision between a fluoroscopy-based robotic total hip arthroplasty platform (FL-RTHA) and a computerized tomography-based (CT-RTHA) platform. The study included 98 consecutive FL-RTHA and 159 CT-RTHA procedures performed via direct anterior approach (DAA). All cases were performed for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Primary outcome variables included cup implantation accuracy and precision (variance). Implantation accuracy was calculated as the absolute value of the difference between pre-operative target cup angles (inclination and anteversion) and the same post-operative angles. Percentage placement in the Lewinnek safe zone was also measured for both cohorts. The FL-RTHA and CT-RTHA cohorts demonstrated a 1.2° difference in absolute values for cup inclination accuracy (4.6° ± 3.6 vs. 3.4 ± 2.7; p = 0.005), and no difference in absolute values for cup anteversion accuracy (4.7° ± 4.1 vs. 4.6 ± 3.4; p = 0.991). Cohorts demonstrated similar precision for cup inclination and anteversion placement parameters, as well as equivalent Lewinnek safe zone placement. The use of a fluoroscopy-based robotic assistance platform for primary DAA THA resulted in similar accuracy and precision of acetabular cup placement when compared to a CT-based robotic assistance system.

Defining the Learning Period of a Novel Imageless Navigation System for Posterior Approach Total Hip Arthroplasty: Analysis of Surgical Time and Accuracy.

Introduction: The use of imageless navigation in total hip arthroplasty (THA) is frequently associated with prolonged surgical times, predominantly during the learning period. The purpose of the present study was to characterize the learning period of a novel imageless navigation system, specifically as it related to surgical time and acetabular navigation accuracy. Materials and Methods: This was a retrospective observational study of a consecutive group of 158 patients who underwent primary unilateral THA for osteoarthritis by a team headed by a single surgeon. All procedures used an imageless navigation system to measure acetabular cup inclination and anteversion angles, referencing a generic sagittal and frontal plane. Navigation accuracy was determined by assessing differences between intraoperative inclination and anteversion values and those obtained from standardized 6-week follow-up radiographs. Operative time and navigation accuracy were assessed by plotting moving averages of 7 consecutive cases. The learning period was defined using Mann-Kendall trend analyses, student t-tests and nonlinear regression modeling based on surgical time and navigation accuracy. Alpha error was 0.05. Results: The average surgical time was 67.3 min (SD:9.2) (range 45-95). The average navigation accuracy for inclination was 0.01° (SD:4.2) (range - 10 to 10), and that for anteversion was - 4.9° (SD:3.8) (range - 14 to 5). Average surgical time and navigation accuracy were similar between the first and final cases in the series with no learning period detected. Conclusions: There was no discernible learning period effect on surgical time or system measurement accuracy during the early phases of adoption for this imageless navigation system.

Fluoroscopy-based robotics in total hip arthroplasty mitigates laterality-based differences in acetabular cup placement when compared to the manual, fluoroscopic- assisted technique.

BACKGROUND: Robotic assistance in total hip arthroplasty (RA-THA) has been shown to minimize laterality-based differences in acetabular cup positioning. OBJECTIVE: To determine if the use of a novel, fluoroscopy-based RA-THA system mitigates differences in acetabular cup placement between left (L) and right (R) side hip procedures, when compared to manual, fluoroscopic-assisted technique. METHODS: We conducted a retrospective review of 106 consecutive mTHA (40 L/66 R) and 102 RA-THA (48 L/54 R) primary direct anterior approach procedures. All cases were performed by a single right-hand-dominant surgeon, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Outcomes included acetabular cup inclination and anteversion, and the proportion of cups within the Lewinnek safe-zone. RESULTS: The average inclination of mTHA L cases was smaller than that of mTHA R cases (41.10∘± 7.38 vs. 43.97∘± 6.27; p= 0.04). For RA-THA, L and R cup angles were similar. There were fewer overall mTHA hips within the Lewinnek safe-zone compared to RA-THA (0.59 vs. 0.78; p= 0.003), as well as fewer mTHA R cases than RA-THA R cases (0.59 vs. 0.80; p= 0.03) within safe zone. CONCLUSION: Use of a novel, fluoroscopy-based robotic system mitigates laterality-based differences in acetabular cup placement that were observed in a manual, fluoroscopic-assisted cohort.

Fluoroscopy-based robotic assistance for total hip arthroplasty improves acetabular cup placement accuracy for obese patients compared to the manual, fluoroscopic- assisted technique.

BACKGROUND: Patient obesity is a risk factor for poor acetabular cup positioning in total hip arthroplasty (THA). OBJECTIVE: To assess the impact of using a novel, fluoroscopy-based robotic THA system on acetabular cup placement in obese versus non-obese patients. METHODS: A review of 105 consecutive manual unassisted (mTHA) (47 Obese/58 Non-obese) and 102 robotic-assisted (RA-THA) (50 Obese/52 Non-obese) primary, direct anterior approach THA procedures was conducted. All cases were performed by a single surgeon, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Obesity was defined as a Body Mass Index (BMI) ⩾ 30 kg/m2. Outcomes included acetabular cup inclination and anteversion, and the proportion of cups within the Lewinnek safe-zone. RESULTS: Obese patients in the mTHA cohort had larger cup inclination angles on average compared to non-obese patients (44.82∘± 6.51 vs. 41.39∘± 6.75; p= 0.009). Obese mTHA patients were less likely to have cup placement within the Lewinnek zone compared to non-obese mTHA patients (0.48 vs. 0.67; p= 0.027). Obesity had no effect on the accuracy of RA-THA. CONCLUSION: Obesity affects the placement of the acetabular component in manual THA. The novel, fluoroscopy-based robotic THA system in this study demonstrated accurate cup placement regardless of obesity status.

Cost-effectiveness of a novel, fluoroscopy-based robotic-assisted total hip arthroplasty system: A Markov analysis.

BACKGROUND: The purpose of this study was to assess the cost-effectiveness of a novel, fluoroscopy-based robotic-assisted total hip arthroplasty (RA-THA) system compared to a manual unassisted technique (mTHA) up to 5 years post-operatively. METHODS: A Markov model was constructed to compare the cost-effectiveness of RA-THA and mTHA. Cost-effectiveness was defined as an Incremental Cost-Effectiveness Ratio (ICER) <$50 000 or $100 000 per Quality Adjusted Life Year (QALY). RESULTS: RA-THA patients experienced lower costs compared to mTHA patients at 1 year ($20 865.12 ± 9897.52 vs. $21 660.86 ± 9909.15; p < 0.001) and 5 years ($23 124.57 ± 10 045.48 vs. $25 756.42 ± 10 091.84; p < 0.001) post-operatively. RA-THA patients also accrued more QALYs (1-year: 0.901 ± 0.117 vs. 0.888 ± 0.114; p < 0.001; 5-years: 4.455 ± 0.563 vs. 4.384 ± 0.537 p < 0.001). Overall, RA-THA was cost-effective (1-year ICER: $-61 210.77; 5-year ICER: $-37 068.31). CONCLUSIONS: The novel, fluoroscopy-based RA-THA system demonstrated cost-effectiveness when compared to manual unassisted THA.

Robotic-assisted total hip arthroplasty utilizing a fluoroscopy-guided system resulted in improved intra-operative efficiency relative to a computerized tomography-based platform.

Robotic-assisted total hip arthroplasty (THA) using a computerized-tomography (CT) based workflow increases surgical time relative to traditional manual technique. The purpose of this investigation was to compare the intra-operative efficiencies of two robotic THA systems: a fluoroscopy-based platform (FL-RTHA) and a contemporary, CT-based (CT-RTHA) platform. A review of 107 consecutive FL-RTHA and 159 CT-RTHA primary, direct anterior approach (DAA) THA procedures was conducted. All cases were performed by one of two surgeons operating at the same institution, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Primary outcome variables included averages and consistencies (variances) for surgical times and operating room (OR) times. A secondary outcome was to quantify the duration of robot-active phases in the FL-RTHA workflow. The FL-RTHA cohort experienced shorter surgical times (38.71 min ± 7.00 vs. 75.33 min ± 11.38; p < 0.001) and OR times (101.35 min ± 12.22 vs. 156.74 min ± 17.79; p < 0.001) compared to the CT-RTHA cohort. Surgical times and OR times were both more consistent in the FL-RTHA cohort compared to the CT-RTHA cohort (p < 0.001). Patients who underwent DAA THA with the assistance of a fluoroscopy-based robotic system experienced shorter and more consistent surgical times and OR times compared to patients who underwent similar DAA THA procedures with a contemporary, CT-based robotic platform.

Ceramic-on-polyethylene hip arthroplasty reduces the risk of postoperative periprosthetic joint infection.

Metal-on-polyethylene (MoP) total hip arthroplasty (THA) prostheses are known to release metal debris. Basic science studies suggest that metal implants induce a pro-inflammatory response that ultimately chemoattracts leukocytes including macrophages and neutrophils to the surgical site. This raises concern of higher risk of infection with these prostheses through the "trojan horse" mechanism by which neutrophils and macrophages transport intracellular pathogens from a remote site. This study compared the infection occurrence between MoP and ceramic-on-polyethylene (CoP) implants to determine if a higher infection rate in MoP is present. We reviewed a consecutive series of 6052 CoP and 4550 MoP primary THA patients from 2015 to 2019. The occurrence of periprosthetic joint infection at 2 years was defined according to the 2018 ICM definition. Statistical analysis consisted of descriptive statistics, univariate analysis, and regression modeling. When compared to CoP, MoP patients were older, included more females, had a higher body mass index, and more commonly affected by comorbidities according to Elixhauser's score. Total revisions were higher in the MoP group (3.19% vs. 2.41%) The absolute incidence of PJI was higher in MoP (2.40% vs. 1.64%). When we adjusted for confounding factors, MoP was found independently associated with a higher PJI risk. Despite MoP and CoP both being widely used for primary THA, we found a higher incidence of PJI in MoP patients. The association remained significant when controlled for possible confounders. We hypothesize that leukocyte recruitment to these implants may play a role and should be further investigated.

Nonagenarians and Octogenarians Undergoing THA and TKA: A 10-Year Age Difference Increases Rates of In-Hospital Complications But Does Not Affect 90-Day Outcomes.

Background: The population of nonagenarians undergoing total joint arthroplasty (TJA) of the hip or knee is expected to increase, but this population may be reluctant to consider elective surgery because of their advanced age. Purpose: We sought to compare TJA outcomes between nonagenarians and octogenarians with an exact 10-year age difference. Methods: We performed a retrospective chart review, including 129 nonagenarians who underwent primary unilateral TJA for osteoarthritis in a 4-year period at a single institution and who were matched with 381 octogenarians based on sex, body mass index, Charlson Comorbidity Index, replaced joint (hip or knee), and a 10-year age difference. Ninety-day outcomes included Centers for Medicare and Medicaid Services (CMS) defined complications, unscheduled outpatient clinic visits, emergency room (ER) visits, and readmissions. No patients were lost to follow-up. Results: Nonagenarians and octogenarians had comparable rates of CMS complications (10% vs 6.3%, respectively), but nonagenarians had higher rates of CMS mechanical complications (6.2% vs 1.6%). There was 1 death in each group. Nonagenarians had longer hospital stays than octogenarians (4.1 vs 3.0 days, respectively), and a greater risk of in-hospital events and complications (60.5% vs 37.3%, respectively). The groups showed similar rates of unscheduled outpatient visits (14.7% vs 13.9%, respectively), ER visits (12.4 vs 6.6%, respectively), and readmissions (6.2% vs 7.1%, respectively). Conclusions: This retrospective study found higher rates of in-hospital complications in nonagenarians than in matched octogenarians following elective TJA, although the 2 groups showed similar rates of postdischarge complications. Further research in a larger cohort is needed.