Acute Kidney Injury After Total Hip and Knee Arthroplasty. What Is the Culprit?

Background: Acute kidney injury (AKI) is associated with increased complications after total hip arthroplasty (THA) and total knee arthroplasty (TKA). The purpose of this study was to determine the risk factors for AKI after THA and TKA and evaluate if preoperative use of antihypertensive drugs is a risk factor for AKI. Methods: A retrospective review of 7406 primary TKAs and THAs (4532 hips and 2874 knees) from 2013 to 2019 was performed. The following preoperative variables were obtained from medical records: medications, chemistry 7 panel, Elixhauser comorbidities, and demographic factors. AKI was defined as an increase in serum creatinine by 26.4 µmol·L-1. Multivariate analysis was performed to identify the risk factors. Results: The overall incidence of postoperative AKI was 6.2% (n = 459). Risk factors for postoperative AKI were found to be: chronic kidney disease (odds ratio [OR] = 7.09; 95% confidence interval [CI]: 4.8-9.4), diabetes (OR: 5.03; 95% CI: 2.8-6.06), ≥3 antihypertensive drugs (OR: 4.2; 95% CI: 2.1-6.2), preoperative use of an angiotensin receptor blockers or angiotensin-converting enzyme inhibitors (OR: 3.8; 95% CI: 2.2-5.9), perioperative vancomycin (OR: 2.7; 95% CI: 1.8-4.6), and body mass index >40 kg/m2 (OR: 1.9; 95% CI: 1.3-3.06). Conclusions: We have identified several modifiable risk factors for AKI that can be optimized prior to an elective THA or TKA. The use of certain antihypertensive agents namely angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and multidrug antihypertensive regimens were found to significantly increase the risk of AKI. Therefore, perioperative management of patients undergoing joint replacement should include medical comanagement with a focus on careful management of antihypertensives.

Bibliometric Analysis of Spinopelvic Alignment in Total Hip Arthroplasty.

INTRODUCTION: Postoperative dislocation of unclear etiology remains a concern after total hip arthroplasty (THA). Interest is growing in the importance of spinopelvic alignment on stability in THA. The purpose of this study was to analyze publication trends, areas of interest, and future research direction of spinopelvic alignment in THA. METHODS: Articles on the topic of spinopelvic alignment in THA published between 1990 and 2022 were obtained through Web of Science Core Collection of Clarivate Analytics (WSCCA). Results were screened by title, abstract, and full text. The inclusion criterion was English-language peer-reviewed journal publications on the clinical topic of spinopelvic alignment in THA. Bibliometric software was used to characterize publication trends. RESULTS: We screened 1,211 articles, yielding 132 meeting the inclusion criterion. From 1990 to 2022, published articles have steadily increased, peaking in 2021. Countries that have been the most productive in contributions to research are those in which THA is the most prevalent. Our analysis of keyword frequency showed increasing interest in "pelvic tilt," "anteversion," and "acetabular component" position. CONCLUSION: Our study identified that increasing attention is being given to spinopelvic mobility and PT in the setting of THA. The United States and France produced the most studies related to spinopelvic alignment.

Dilute Povidone-Iodine Irrigation Reduces the Rate of Periprosthetic Joint Infection Following Hip and Knee Arthroplasty: An Analysis of 31,331 Cases.

BACKGROUND: Total joint arthroplasty (TJA) surgeons employ various strategies to reduce the risk of periprosthetic joint infection (PJI). Few studies have examined the efficacy of preclosure dilute povidone-iodine irrigation in a large cohort accounting for recent practice changes in TJA. This study compared the risk of PJI in TJA patients with and without dilute povidone-iodine irrigation. METHODS: This is a retrospective study of all consecutive primary TJAs between 2009 and 2019 at a single institution. We included 31,331 cases, of which 8659 were irrigated with dilute povidone-iodine and 22,672 were irrigated with sterile saline prior to closure. The primary endpoint was PJI as defined by 2018 International Consensus Meeting criteria with a minimum follow-up of 1 year. Multivariate logistic regression was used to determine the association between dilute povidone-iodine irrigation and PJI while controlling for demographics, comorbidities, and operative factors. RESULTS: In total, 340 patients (1.09%) developed PJI. Dilute povidone-iodine irrigation was associated with 2.34 times lower rate of PJI (0.6% vs 1.3%). Using multiple regression, dilute povidone-iodine remained significantly associated with a reduction in PJI. The absolute risk reduction was 0.73% and number needed to treat was 137 patients. Female gender, American Society of Anesthesiologists score, operative time, anesthesia type, prophylactic antibiotic type, and tranexamic acid were other significant factors in the regression model. CONCLUSION: The routine use of dilute povidone-iodine could prevent 1 PJI for every 137 TJA patients, regardless of their preoperative risk. These findings support the use of povidone-iodine irrigation as a safe and cost-effective measure to reduce PJI.

Staging Total Hip and Knee Arthroplasty Procedures Within 90 Days Increases Costs in Bundled Payment Programs.

BACKGROUND: Under current Medicare bundled payment programs, when a patient undergoes a subsequent elective procedure within the 90-day episode-of-care, the first procedure is excluded from the bundle and a new episode-of-care initiated. The purpose of this study was to determine if staging bilateral total hip (THA) and total knee arthroplasty (TKA) procedures within 90 days have an effect on bundled episode-of-care costs. METHODS: We reviewed a consecutive series of Medicare patients undergoing staged primary THA and TKA from 2015-2019. Patients who underwent a prior procedure within 90 days were compared to those who had undergone a procedure 90-120 days prior. We then performed a multivariate analysis to identify the independent effect of staging timeframe on costs and outcomes. RESULTS: Of the 136 patients undergoing a staged bilateral THA or TKA, 48 patients underwent staged procedures within 90 days (35%) and 88 patients between 91-120 days (65%). There were no significant differences observed for demographics, comorbidities, complications, readmissions, or discharge disposition (all P > .05). Patients undergoing a staged procedure within 90 days had increased episode-of-care costs by $2021 (95% CI $11-$4032, P = .049), increased postacute care costs by $2019 (95% CI $66-$3971, P < .001), and reduced per-patient margin by $2868 (95% CI-$866-$4869, P = .005). DISCUSSION: Patients undergoing staged bilateral THA or TKA within 90 days have increased episode-of-care costs compared to those undergoing a staged procedure from 91-120 days. Since patients may still not be fully recovered from the first procedure, CMS should address the inappropriate allocation of costs to ensure institutions are not penalized.

The Use of Cementless Components Does Not Significantly Increase Procedural Costs in Total Knee Arthroplasty.

BACKGROUND: Modern cementless total knee arthroplasty (TKA) designs have shown promising early clinical success; however, concerns exist regarding the higher cost of the cementless implants. The purpose of this study is to evaluate the total facility cost of cementless vs traditional cemented TKA along with the effect of cementless fixation on short-term outcomes. METHODS: We reviewed a consecutive series of patients between 2015 and 2017 who underwent either cementless or cemented primary TKA. Itemized facility costs were calculated for every procedure using a time-driven activity-based costing algorithm. Controlling for demographic variables and medical comorbidities, we performed a multivariate analysis to identify independent risk factors for facility costs following TKA. Short-term outcome metrics including complications, readmissions, and patient-reported outcomes were compared between groups. RESULTS: Among the 2426 primary TKA patients in this study, 119 (4.91%) were performed using cementless implants. When compared to cemented TKA, cementless TKA patients had higher implant costs ($3047.80 vs $2808.73, P < .0001), but lower supply costs ($639.49 vs $815.57, P < .0001) and lower operating room personnel costs ($982.01 vs $1238.26, P < .0001). When controlling for confounding variables, cementless fixation did not have a significant effect on total facility cost or outcomes. CONCLUSION: In conclusion, the use of cementless TKA implants did not significantly increase total procedural costs when compared to traditional cemented TKA components at our institution. Our data suggest that the increased cost of a cementless implant is recouped through savings in cost of cement and supplies, as well as shorter operative times. The authors encourage investigators at other institutions to use the authors' methodology to evaluate (preferably in a prospective manner) whether the findings from this study can be corroborated.

Costs and Outcomes of Medicare Advantage and Traditional Medicare Beneficiaries After Total Hip and Knee Arthroplasty.

INTRODUCTION: Medicare Advantage (MA) has increased popularity among eligible participants by providing additional benefits from a private insurer, but these plans are omitted from several government cost savings programs, including bundled payment models. The purpose of this study was to determine whether 90-day episode-of-care (EOC) costs and outcomes were different for patients with MA plans undergoing total joint arthroplasty compared with traditional Medicare patients. METHODS: We reviewed claims data for a consecutive series of patients undergoing primary total hip and knee arthroplasty from 2015 to 2018 at our institution with traditional Medicare coverage or MA through a single private insurer. Demographics, comorbidities, 90-day costs, readmissions, complications, and discharge disposition were compared between the groups. A multivariate regression analysis was performed to determine the independent effect of insurance status on EOC costs and outcomes. RESULTS: Of the 10,869 patients in the study, 1,076 (9.9%) were covered under an MA plan. MA patients were more likely to be discharged to a rehabilitation facility (19% versus 14%, P < 0.0001). No significant differences were observed in length of stay (1.88 versus 1.88 days, P = 0.1439), complications (3.9% versus 3.5%, P = 0.4554), or readmissions (5.9% versus 4.9%, P = 0.1893). EOC costs were significantly higher for the MA group ($21,347 versus $19,551, P < 0.0001). DISCUSSION: Patients with MA have higher total EOC costs than traditional Medicare beneficiaries with comparable short-term outcomes after total hip and knee arthroplasty. Further study is needed to determine whether alternative payment models in MA patients can improve care and reduce costs.

Conversion Total Knee Arthroplasty is Associated with Increased Post-Acute Care Costs.

BACKGROUND: Alternative payment models have been viewed as successfully decreasing costs following primary total knee arthroplasty (TKA) while maintaining quality. Concerns exist regarding access to care for patients who may utilize more resources in a bundled payment arrangement. The purpose of this study is to determine if patients undergoing conversion of prior surgery to TKA have increased costs compared to primary TKA patients. METHODS: Claims from Medicare and a single private insurer were queried for all primary TKA patients at our institution from 2015 to 2016. Ninety-day post-acute care costs were compared between primary and conversion TKA. Secondary endpoints included discharge disposition, complications, and readmissions. A multivariate regression analysis was performed to identify independent risk factors for increased post-acute care costs and short-term outcome metrics. RESULTS: Of 3999 primary TKA procedures, 948 patients (23%) underwent conversion TKA. Conversion TKA was associated with greater post-acute care costs in patients with commercial insurance ($4714 vs $3759, P = .034). Among Medicare beneficiaries, prior ligament reconstruction was associated with increased post-acute care costs ($1917 increase, P = .036), while prior fracture fixation approached statistical significance ($2402 increase, P = .055). Conversion TKA was an independent risk factor for readmissions (odds ratio 1.46, 95% confidence interval 1.00-2.17, P = .050), while patients with a prior open knee procedure had higher rates of complications (odds ratio 2.41, 95% confidence interval 1.004-5.778, P = .049). CONCLUSION: Our data suggest that conversion from prior knee surgery to TKA is associated with increased 90-day post-acute care costs and resource utilization, particularly prior open procedures. Without appropriate risk adjustment in alternative payment models, surgeons may be financially deterred from providing quality arthroplasty care given the reduced net payment and surgical complexity of such cases.