Background: Substance abuse disorder (SUD), alcohol abuse disorder (AUD), and depression have been identified as independent risk factors for complications after total knee arthroplasty (TKA). However, these mental health disorders are highly co-associated, and their cumulative effect on postoperative complications have not been investigated. Therefore, this study aimed to determine if patients who have more than one mental health disorder (SUD, AUD, or depression) were at an increased risk for postoperative complications following TKA. Methods: A total of 11,403 TKA patients were identified from a prospectively collected institutional database between January 1, 2017 and April 1, 2019. Patients who had depression, SUD, and AUD were separated into 7 mental health subgroups including each of these diagnoses alone and their combined permeations. Patient demographics, body mass indices, medical comorbidities, and 15 postoperative complications were collected. Univariate analyses were performed using independent Student's t-tests. Multivariate analyses were then performed to identify odds ratios (ORs) for mental health disorders subgroups associated with complications. Results: We found a total of 2073 (18%) patients diagnosed with either SUD (4%), AUD (0.6%), or depression (12%). Univariate analyses showed that depression was associated with mechanical failures (P < .001). SUD was associated with periprosthetic joint infection (PJI) (P < .001), wound complications (P ¼ .022), and aseptic loosening (P ¼ .007). AUD was associated with PJI (P < .001) and deep vein thromboses (P ¼ .003). Multivariate analyses found that AUD (OR: 19.419, P < .001) and SUD (OR:3.693, P ¼.010) were independent risk factors for PJI. Compared with SUD alone, patients with depression plus SUD were found to have a 4fold (OR: 13.639, P < .001) and 2-fold (OR:4.401, P ¼ .021) increased risk for PJI and cellulitis, respectively. Conclusions: Patients who had depression, SUD, or AUD were at increased risk for postoperative complications following primary TKA. When patients have more than one mental health diagnosis, their risk for complications was amplified. The results of this study can help identify those patients who are at greater risk of postoperative complications to enable improved preoperative optimization and patient education.

Background: Revision total knee arthroplasty (TKA) is associated with increased rates of infections, readmissions, longer operative times, and lengths-of-stay (LOS) compared to primary TKA. Additionally, increasing operative times and prolonged postoperative LOS are independent risk factors for these postoperative complications in lower extremity total joint arthroplasty (TJA). This has led to an increased effort to reduce these risk factors in order to improve patient outcomes and reduce cost. However, the relationship between operative time and LOS has not been well assessed in revision arthroplasty. Therefore, the purpose of this study was to: (I) identify predictors of longer operative times; (II) identify predictors of longer LOS; and (III) evaluate the effects of operative time, treated as both a categorical variable and a continuous variable, on LOS after revision TKA. Methods: The NSQIP database was queried for all revision TKA cases (CPT code 27487) between 2008 and 2016 which yielded 10,604 cases. Mean operative times were compared between patient demographics including age groups, sex, and body mass indexes (BMIs). To determine predictors of LOS, mean LOS were also compared between patient demographics in the same groups. To assess the correlation of operative time on LOS, the mean LOS for 30-minute operative time intervals were compared. Univariate analysis was performed with one-way analysis of variance (ANOVA) and t-tests. A multivariate analysis with a multiple linear regression model was performed to evaluate the association of LOS with operative times after adjusting for patient age, sex, and BMI. Results: The mean LOS for revision TKA was 4 (±3) days. Further analysis showed that young age is associated with increased LOS (P<0.01). An analysis of operative times showed positive correlations with young age, BMI greater than 30 and male sex (P<0.05). The mean LOS of revision TKA patients was found to increase with increasing operative time in 30-minute intervals (P<0.001). Multivariate analysis showed that longer operative times had significant associations with longer LOS even after adjusting for patient factors (β=0.102, SE =0.001, P<0.001). These results also showed that out of all of the study covariates, operative times had the greatest effect on LOS after revision TKA. Conclusions: Revision TKA is a complex procedure, often requiring increased operative times compared to primary TKA. This study provides unique insight by correlating operative times to LOS in over 10,000 revision TKAs from a nationwide database. Our results demonstrate that out of all the study covariates (age, sex, and BMI), operative times had the greatest effect on LOS. The results from this study indicate that less time spent in the operating room can lead to shorter LOS for revision TKA patients. This relationship further underscores the need for improved preoperative planning and intra-operative efficiency in an effort to decrease LOS and improve patient outcomes.

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Background: Relative value units (RVUs) are a physician reimbursement model based on the effort required, or value, in providing a procedure or service for a patient. Procedures such as conversion total hip arthroplasties (THAs) can be compared to primary THAs, but many studies have revealed increased difficulties in conversion cases. Despite the increased time and effort for conversion THA, it is unknown if this is reflected in the RVU compensation model. Therefore, the purpose of this study was to compare the: (I) mean operative times; (II) mean RVUs; (III) RVU/minute for primary and conversion THAs; and (IV) perform an individualized idealized surgeon annual cost difference analysis.Methods: A total of 103,702 primary THA patients were identified using CPT code 27130 and 2,986 conversion THA patients were identified using CPT code 27132 using the National Surgical Quality Improvement Program (NSQIP) database. The mean RVUs, operative times (minutes), and RVU/minute were calculated and compared. An annualize cost analysis of dollar amounts per case, day, and the year was also performed. Results:The mean operative times for the primary and conversion THA cohorts were 94 vs. 146 minutes (P<0.001) and mean RVUs were 21.24 vs. 25.68 (P<0.001). Interestingly, the mean RVU per minute was higher for the primary THA compared to the conversion THA groups (0.26 vs. 0.21, P<0.001). Annualized cost analysis revealed a potential $173,529 difference from performing primary vs. conversion THAs.Conclusions: Even though conversion THA can be considered to a more complex and demanding procedure, based on RVUs per minute of surgery, orthopaedic surgeons are reimbursed better for primary THA cases. This data could be used by orthopaedic surgeons to administer their practices better to yield the highest return on time.