Ninety-Day Costs, Reoperations, and Readmissions for Primary Total Hip Arthroplasty Patients of Varying Body Mass Index Levels.

BACKGROUND: The purpose of this study is to compare 90-day costs and outcomes for primary total hip arthroplasty patients between a nonobese (body mass index, 18.5-24.9) vs overweight (25-29.9), obese (30-34.9), severely obese (35-39.9), morbidly obese (40-44.9), and super obese (45+) cohorts. METHODS: We conducted a retrospective review of an institutional database of primary total hip arthroplasty patients from 2006 to 2013. Thirty-three super-obese patients were identified, and the other 5 cohorts were randomly selected in a 2:1 ratio (n = 363). Demographics, 90-day outcomes (costs, reoperations, and readmissions), and outcomes after 3 years (revisions and change scores for Short-Form Health Survey, Harris Hip Score, and Western Ontario and McMaster Universities Arthritis Index) were collected. Costs were determined using unit costs from our institutional administrative data for all in-hospital resource utilization. Comparisons between the nonobese and other groups were made with Kruskal-Wallis tests for non-normal data and chi-square and Fisher exact test for categorical data. RESULTS: The 90-day costs in the morbidly obese ($13,134 ± $7250 mean ± standard deviation, P < .01) and super-obese ($15,604 ± 6783, P < .01) cohorts were significantly greater than the nonobese cohorts ($10,315 ± 1848). Only the super-obese cohort had greater 90-day reoperation and readmission rates than the nonobese cohort (18.2% vs 0%, P < .01 and 21.2% vs 4.5%, P = .02, respectively). Reoperations and septic revisions after 3 years were greater in the super-obese cohort compared to the nonobese cohort 21.2% versus 3.0% (P = .01) and 18.2% versus 1.5% (P = .01), respectively. Improvements in Short-Form Health Survey, Harris Hip Score, and Western Ontario and McMaster Universities Arthritis Index were comparable in all cohorts. CONCLUSION: Super-obese patients have greater risks and costs compared to nonobese patients, but also have comparable quality of life improvements.

Cost-Effectiveness of Total Hip Arthroplasty Versus Nonoperative Management in Normal, Overweight, Obese, Severely Obese, Morbidly Obese, and Super Obese Patients: A Markov Model.

BACKGROUND: We estimated the cost-effectiveness of performing total hip arthroplasty (THA) vs nonoperative management (NM) among 6 body mass index (BMI) cohorts. METHODS: We constructed a state-transition Markov model to compare the cost utility of THA and NM in the 6 BMI groups over a 15-year period. Model parameters for transition probability (risk of revision, re-revision, and death), utility, and costs (inflation adjusted to 2017 US dollars) were estimated from the literature. Direct medical costs of managing hip arthritis were accounted in the model. Indirect societal costs were not included. A 3% annual discount rate was used for costs and utilities. The primary outcome was the incremental cost-effectiveness ratio (ICER) of THA vs NM. One-way and Monte Carlo probabilistic sensitivity analyses of the model parameters were performed to determine the robustness of the model. RESULTS: Over the 15-year time period, the ICERs for THA vs NM were the following: normal weight ($6043/QALYs [quality-adjusted life years]), overweight ($5770/QALYs), obese ($5425/QALYs), severely obese ($7382/QALYs), morbidly obese ($8338/QALYs), and super obese ($16,651/QALYs). The 2 highest BMI groups had higher incremental QALYs and incremental costs. The probabilistic sensitivity analysis suggests that THA would be cost-effective in 100% of the normal, overweight, obese, severely obese, and morbidly obese simulations, and 99.95% of super obese simulations at an ICER threshold of $50,000/QALYs. CONCLUSION: Even at a willingness-to-pay threshold of $50,000/QALYs, which is considered low for the United States, our model showed that THA would be cost-effective for all obesity levels. BMI cut-offs for THA may lead to unnecessary loss of healthcare access.

Cost-Effectiveness of Total Knee Arthroplasty vs Nonoperative Management in Normal, Overweight, Obese, Severely Obese, Morbidly Obese, and Super-Obese Patients: A Markov Model.

BACKGROUND: We estimated the cost-effectiveness of performing total knee arthroplasty (TKA) vs nonoperative management (NM) among 6 body mass index (BMI) cohorts. METHODS: A Markov model was used to compare the cost-utility of TKA and NM in 6 BMI groups (nonobese [BMI 18.5-24.9], overweight [25-29.9], obese [30-34.9], severely obese [35-39.9], morbidly obese [40-49.9], and super-obese [50+] patients) over a 15-year period. Model parameters for transition probability (ie, revision, re-revision, death), utility, and costs were estimated from the literature. Direct medical costs but not indirect societal costs were included in the model. Costs and utilities were discounted 3% annually. The primary outcome was the incremental cost-effectiveness ratio (ICER) of TKA vs NM. One-way and probabilistic sensitivity analyses of the model parameters were performed to determine the robustness of the model. RESULTS: Over the 15-year period, the ICERs for the TKA vs NM for the different BMI categories were nonobese ($3317/quality-adjusted life years [QALYs]), overweight ($2837/QALY), obese ($2947/QALY), severely obese ($3536/QALY), morbidly obese ($5531/QALY), and super-obese ($11,878/QALY). The higher BMI groups tended to have higher incremental QALYs and also higher incremental costs. The probabilistic sensitivity analysis with an ICER threshold of $30,000/QALY showed that TKA would be cost-effective in 100% of simulations of patients with a BMI<50 and 99.16% of super-obese simulations. CONCLUSION: While performing TKA on super-obese patients is more expensive, the substantial improvements in patient outcomes make it cost-effective. Therefore, withholding TKA care based on a BMI would lead to an unjustified loss of health-care access.

Ninety-Day Costs, Reoperations, and Readmissions for Primary Total Knee Arthroplasty Patients With Varying Body Mass Index Levels.

BACKGROUND: We compared 90-day costs and outcomes for primary total knee arthroplasty patients among nonobese (body mass index [BMI] 18.5-24.9), overweight (25-29.9), obese (30-34.9), severely obese (35-39.9), morbidly obese (40-49.9), and super-obese (50+) cohorts. METHODS: We conducted a retrospective review of an institutional database of total knee arthroplasty patients from 2006 to 2013 with a minimum of 3-year follow-up. Sixty-five super-obese patients were identified, and five other cohorts were randomly selected in a 2:1 ratio (total, n = 715). Demographics, 90-day outcomes (costs, reoperations, and readmissions), and outcomes after 3 years (revisions and change scores for Short-Form Health Survey [SF-12], Knee Society Scores, and Western Ontario and McMaster Universities Arthritis Index) were aggregated. RESULTS: The 90-day costs were significantly greater in the morbidly obese ($11,568 ± $1,960) and super-obese ($14,021 ± $7,903) cohorts relative to the smaller BMI cohorts ($9,938 - $10,352). The increased cost from readmissions was the main driver of costs. The outcome change scores were similar across all the BMI cohorts for Knee Society Scores, SF-12 Mental Health Composite Score, and Western Ontario and McMaster Universities Arthritis Index, but not for the SF-12 Physical Health Composite Score. At the midterm follow-up, there was no statistical difference in repeat surgery or aseptic revision rates. Septic revisions were significantly greater in the super-obese cohort relative to the other cohorts (6.2% vs 0.8-3.1%). CONCLUSION: Health-care policy based purely on the economic costs may place morbidly obese and super-obese patients at risk of losing arthroplasty care, thereby denying them access to the comparable quality of life improvements.

Post-Discharge Care Duration, Charges, and Outcomes Among Medicare Patients After Primary Total Hip and Knee Arthroplasty.

BACKGROUND: In April 2016, the U.S. Centers for Medicare & Medicaid Services initiated mandatory 90-day bundled payments for total hip and knee arthroplasty for much of the country. Our goal was to determine duration of care, 90-day charges, and readmission rates by discharge disposition and U.S. region after hip or knee arthroplasty. METHODS: Using the 2008 Medicare Provider Analysis and Review database 100% sample, we identified patients who had undergone elective primary total hip or knee arthroplasty. We collected data on patient age, sex, comorbidities, U.S. Census region, discharge disposition, duration of care, 90-day charges, and readmission. Multivariate regression was used to assess factors associated with readmission (logistic) and charges (linear). Significance was set at p < 0.01. RESULTS: Patients undergoing 138,842 total hip arthroplasties were discharged to home (18%), home health care (34%), extended-care facilities (35%), and inpatient rehabilitation (13%); patients undergoing 329,233 total knee arthroplasties were discharged to home (21%), home health care (38%), extended-care facilities (31%), and inpatient rehabilitation (10%). Patients in the Northeast were more likely to be discharged to extended-care facilities or inpatient rehabilitation than patients in other regions. Patients in the West had the highest 90-day charges. Approximately 70% of patients were discharged home from extended-care facilities, whereas after inpatient rehabilitation, >50% of patients received home health care. Among those discharged to home, 90-day readmission rates were highest in the South (9.6%) for patients undergoing total hip arthroplasty and in the Midwest (8.7%) and the South (8.5%) for patients undergoing total knee arthroplasty. Having ≥4 comorbidities, followed by discharge to inpatient rehabilitation or an extended-care facility, had the strongest associations with readmission, whereas the region of the West and the discharge disposition to inpatient rehabilitation had the strongest association with higher charges. CONCLUSIONS: Among Medicare patients, discharge disposition and number of comorbidities were most strongly associated with readmission. Inpatient rehabilitation and the West region had the strongest associations with higher charges. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Inpatient Mortality and Morbidity for Dialysis-Dependent Patients Undergoing Primary Total Hip or Knee Arthroplasty.

BACKGROUND: Dialysis-dependent patients can develop osteoarthritis or osteonecrosis, warranting hip or knee arthroplasty. Their comorbidities predispose them to complications. Our goal was to determine inpatient outcomes of dialysis-dependent patients after primary elective total hip or knee arthroplasty. METHODS: In the National Inpatient Sample, we identified 2934 dialysis-dependent patients who had undergone total hip or knee arthroplasty from 2000 through 2009 and compared them with 6,186,475 patients who had undergone the same procedures and were not dialysis-dependent. We described demographic characteristics, comorbidities, and outcomes and assessed associations of dialysis status with inpatient mortality and complications. RESULTS: In the hip arthroplasty group, dialysis-dependent patients were younger (63.2 compared with 65.2 years; p = 0.0476) and more commonly diagnosed with osteonecrosis (34.29% compared with 10.94%; p < 0.0001) than non-dialysis-dependent patients. Dialysis-dependent patients had higher inpatient mortality rates (1.88% compared with 0.13%; p < 0.0001) and greater overall complication rates (9.98% compared with 4.97%; p = 0.0001). Dialysis was an independent risk factor for mortality (odds ratio, 6.66; 95% confidence interval [95% CI], 2.66 to 16.66) and complications (odds ratio, 1.53; 95% CI, 1.01 to 2.33). In the knee arthroplasty group, dialysis-dependent patients were similar in age (66.7 compared with 66.8 years; p = 0.8085) and were more commonly diagnosed with osteonecrosis (3.32% compared with 0.74%; p < 0.0001) than non-dialysis-dependent patients. Dialysis-dependent patients had higher inpatient mortality rates (0.92% compared with 0.10%; p < 0.0001) and greater overall complication rates (12.48% compared with 5.00%; p < 0.0001). Dialysis status was an independent risk factor for mortality (odds ratio, 3.31; 95% CI, 1.04 to 10.54) and complications (odds ratio, 1.86; 95% CI, 1.34 to 2.60). CONCLUSIONS: Total hip and knee arthroplasty in dialysis-dependent patients presents high risk, with inpatient mortality rates ten to twenty times greater and overall complication rates two times greater than in non-dialysis-dependent patients. Arthroplasty should be approached with caution and preferably should be delayed until after renal transplantation.

Functional assessment of the acute local and distal transplantation of human neural stem cells after spinal cord injury.

BACKGROUND CONTEXT: Spinal cord injury can lead to severe functional impairments secondary to axonal damage, neuronal loss, and demyelination. The injured spinal cord has limited regrowth of damaged axons. Treatment remains controversial, given inconsistent functional improvement. Previous studies demonstrated functional recovery of rats with spinal cord contusion after transplantation of rat fetal neural stem cells. PURPOSE: We hypothesized that acute transplantation of human fetal neural stem cells (hNSCs) both locally at the injury site as well as distally via intrathecal injection would lead to improved functional recovery compared with controls. STUDY DESIGN/SETTING: Twenty-four adult female Long-Evans hooded rats were randomized into four groups with six animals in each group: two experimental and two control. Functional assessment was measured after injury and then weekly for 6 weeks using the Basso, Beattie, and Bresnahan Locomotor Rating Score. Data were analyzed using two-sample t test and linear mixed-effects model analysis. METHODS: Posterior exposure and laminectomy at T10 level was used. Moderate spinal cord contusion was induced by the Multicenter Animal Spinal Cord Injury Study Impactor with 10-g weight dropped from a height of 25 mm. Experimental subjects received either a subdural injection of hNSCs locally at the injury site or intrathecal injection of hNSCs through a separate distal laminotomy. Controls received control media injection either locally or distally. RESULTS: Statistically significant functional improvement was observed in local or distal hNSCs subjects versus controls (p=.034 and 0.016, respectively). No significant difference was seen between local or distal hNSC subjects (p=.66). CONCLUSIONS: Acute local and distal transplantation of hNSCs into the contused spinal cord led to significant functional recovery in the rat model. No statistical difference was found between the two techniques.