Risk of Acute Kidney Injury After Primary and Revision Total Hip Arthroplasty and Total Knee Arthroplasty Using a Multimodal Approach to Perioperative Pain Control Including Ketorolac and Celecoxib

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.

Impact of intra- and extramedullary alignment on blood loss in total knee arthroplasty: a retrospective study

BACKGROUND

There is a scarcity of scientific data regarding the correlation between alignment techniques during total knee arthroplasty (TKA) and blood loss as well as transfusion rates. This study's hypothesis posited that intramedullary-aligned (IM) TKA exhibits higher blood loss and transfusion rates when contrasted with extramedullary-aligned (EM) TKA.

METHODS

We conducted a retrospective examination of 883 patients who underwent total knee arthroplasty (TKA) in 2021 at a solitary orthopedic center in Germany. These patients were divided into two groups based on their tibial alignment technique: extramedullary alignment and intramedullary tibial alignment.

RESULTS

In the intramedullary tibial alignment (IM) group, we observed a blood loss of 0.91 L, while in the extramedullary tibial alignment (EM) group, the blood loss was 0.89 L. These values did not demonstrate a significant difference (p = 0.69). Transfusion rates were 0.99% in the IM group and 0.21% in the EM group, and there was no significant distinction between them (Chi-squared test: p > 0.05).

CONCLUSION

We observed no statistically significant variance in blood loss between the IM and EM groups. Likewise, there was no substantial disparity in transfusion rates between these groups. It can be concluded that the selection of a knee arthroplasty system incorporating either intramedullary tibial alignment or extramedullary alignment does not significantly impact blood loss.

The incidence and risk factors for abnormal postoperative blood tests following primary total joint replacement

Aims

We aim to evaluate the usefulness of postoperative blood tests by investigating the incidence of abnormal results following total joint replacement (TJR), as well as identifying preoperative risk factors for abnormal blood test results postoperatively, especially pertaining to anaemia and acute kidney injury (AKI).

Methods

This is a retrospective cohort study of patients who had elective TJR between January and December 2019 at a tertiary centre. Data gathered included age at time of surgery, sex, BMI, American Society of Anesthesiologists (ASA) grade, preoperative and postoperative laboratory test results, haemoglobin (Hgb), white blood count (WBC), haematocrit (Hct), platelets (Plts), sodium (Na+), potassium (K+), creatinine (Cr), estimated glomerular filtration rate (eGFR), and Ferritin (ug/l). Abnormal blood tests, AKI, electrolyte imbalance, anaemia, transfusion, reoperation, and readmission within one year were reported.

Results

The study included 2,721 patients with a mean age of 69 years, of whom 1,266 (46.6%) were male. Abnormal postoperative bloods were identified in 444 (16.3%) patients. We identified age (≥ 65 years), female sex, and ASA grade ≥ III as risk factors for developing abnormal postoperative blood tests. Preoperative haemoglobin (≤ 127 g/dl) and packed cell volume (≤ 0.395 l/l) were noted to be significant risk factors for postoperative anaemia, and potassium (≤ 3.7 mmol/l) was noted to be a significant risk factor for AKI.

Conclusion

The costs outweigh the benefits of ordering routine postoperative blood tests in TJR patients. Clinicians should risk-stratify their patients and have a lower threshold for ordering blood tests in patients with abnormal preoperative haemoglobin (≤ 127 g/l), blood loss > 300 ml, chronic kidney disease, ASA grade ≥ III, and clinical concern.

Comparison between ketorolac- and fentanyl-based patient-controlled analgesia for acute kidney injury after robot-assisted radical prostatectomy: a retrospective propensity score-matched analysis

PURPOSE

It is unclear whether ketorolac-based patient-controlled analgesia (PCA) leads to acute kidney injury (AKI) after robot-assisted radical prostatectomy (RARP) in patients susceptible to AKI. We compared the postoperative AKI incidence with ketorolac- and fentanyl-based PCA after RARP.

METHODS

After medical record review, eligible patients were divided in ketorolac and fentanyl groups. We conducted propensity score matching of 3239 patients and assigned 641 matched patients to each group, and compared the AKI incidence. We investigated potential risk factors for postoperative AKI, defined according to the Kidney Disease Improving Global Outcomes criteria. We collected preoperative data (age, height, weight, body mass index, American Society of Anesthesiologists physical status, medical history, creatinine level, estimated glomerular filtration rate, and hemoglobin level) and intraoperative data (maintenance anesthetics, surgery duration, anesthesia duration, crystalloid amount, colloid use, total amount of fluid administered, estimated blood loss, norepinephrine use, phenylephrine use, and PCA type).

RESULTS

The postoperative AKI incidence was significantly higher in the ketorolac than in the fentanyl group, both before (31.1% vs. 20.4%; p < 0.001) and after (31.5% vs. 22.6%; p < 0.001) matching. In the univariate analysis, ketorolac was significantly associated with postoperative AKI, both before (odds ratio [OR], 1.762; 95% confidence interval [CI], 1.475-2.105; p < 0.001) and after (OR, 1.574; 95% CI, 1.227-2.019; p < 0.001) matching. In the multivariate analysis, ketorolac-based PCA was independently associated with development of postoperative AKI in the matched groups (OR, 1.659; 95% CI, 1.283-2.147; p < 0.001).

CONCLUSION

Ketorolac-based PCA may increase postoperative AKI incidence after RARP; thus, renal function should be monitored in these patients.

Improving Postoperative Acute Kidney Injury Rates Following Primary Total Joint Arthroplasty

BACKGROUND

Perioperative hip and knee arthroplasty complications remain a significant clinical and financial burden. Our institution has shifted to developing protocols to decrease these perioperative complications. This study focuses on acute kidney injury (AKI) rate status post primary total joint arthroplasty (TJA). Current literature demonstrates a 2%-15% incidence of AKI following TJA. However, there is a paucity of published literature on protocols that have effectively reduced AKI rates following TJA. The purpose of this study is to evaluate the effect that our institutionally developed perioperative renal protocol had on the postoperative AKI rates.

METHODS

A retrospective cohort study was performed. Patient demographics, baseline creatinine, and postoperative creatinine values during the patient's hospitalization were collected and analyzed. The preintervention cohort data contained all patients at our institution who underwent a primary TJA from November 1, 2016 to January 1, 2018. The postintervention cohort included all primary TJA patients from July 1, 2018 to February 2, 2020. AKI was defined using the AKI Network classification system comparing baseline and postoperative creatinine values. A multivariate analysis was performed to determine the statistical significance of our results.

RESULTS

Before intervention 1013 patients underwent a primary TJA with 68 patients developing an AKI postoperatively. After intervention 2169 patients underwent primary TJA with 90 patients developing an AKI (6.71% vs 4.15%; P = .0015, odds ratio = 0.59, 95% confidence interval = 0.42-0.82).

CONCLUSION

This study demonstrated that implementation of a perioperative renal protocol can significantly reduce AKI rates. A reduction in AKI rates following TJA will result in improved outcomes and secondarily decrease the financial impact of postoperative complications seen following TJA.

Postoperative Acute Kidney Injury With Dual NSAID Use After Outpatient Primary Total Joint Arthroplasty

BACKGROUND

NSAIDs have been shown to be highly effective analgesic agents in the postoperative period. NSAIDs do have several potential adverse effects, including kidney injury (AKI). Little is known about AKI in the outpatient total joint arthroplasty (TJA) setting, where patient labs are not closely monitored. The objective of this study was to evaluate the renal safety of combined use of ibuprofen for pain control and aspirin for deep vein thrombosis chemoprophylaxis after outpatient primary TJA.

METHODS

Patients undergoing primary total hip or total knee arthroplasty between January 2020 and July 2020 at a single center were included for analysis. All included patients were discharged on a standard regimen including aspirin 81 mg twice a day and ibuprofen 600 mg three times a day. Patients were ordered a serum creatinine test at 2 and 4 weeks postoperatively. Patients with postoperative acute kidney injury were identified per Acute Kidney Injury Network criteria.

RESULTS

Between January 23, 2020, and August 30, 2020, 113 patients were included in this study, of whom creatinine levels were measured in 103 patients (90.3%) at the 2-week postoperative time point, 58 patients (50.9%) at the 4-week time point, and 48 (42.1%) at combined 2- and 4-week time points. Three patients (2.9%) were found to have an AKI.

CONCLUSION

This study found a rate of AKI of 2.9% with the use of dual NSAID therapy postoperatively after primary TJA. All cases occurred at 2 weeks postoperatively and saw spontaneous resolution.

High-Dose Antibiotic Cement Spacers Independently Increase the Risk of Acute Kidney Injury in Revision for Periprosthetic Joint Infection: A Prospective Randomized Controlled Clinical Trial

BACKGROUND

Standard treatment for periprosthetic joint infection (PJI) involves 2-stage exchange with placement of an antibiotic-impregnated cement spacer (ACS). Conflicting evidence exists on the role of ACS in development of acute kidney injury (AKI) after first-stage surgery. In this randomized clinical trial, we aimed to compare the incidence of AKI between the first-stage of a planned 2-stage exchange vs 1-stage exchange. This study design isolates the effect of the ACS in otherwise identical treatment groups.

METHODS

The primary outcome variable was AKI, defined as a creatinine ≥1.5 times baseline or an increase of ≥0.3 mg/dL. Risk factors for AKI were evaluated using bivariate statistical tests and multivariable logistic regression.

RESULTS

Patients who underwent the first stage of a planned 2-stage exchange were significantly more likely to develop AKI compared with the 1-stage exchange group (15 [22.7%] vs 4 [6.6%], P = .011). On multivariable regression analysis, ACS placement (odds ratio 7.48, 95% confidence limit 1.77-31.56) and chronic kidney disease (odds ratio 3.84, 95% confidence limit 1.22-12.08) were independent risk factors for AKI.

CONCLUSION

Our study provides evidence that high-dose antibiotic cement spacers for treatment of PJI are an independent risk factor for AKI. Therefore, efforts to minimize nephrotoxicity should be employed in revision for PJI when possible.

Intraoperative hypotension is associated with persistent acute kidney disease after noncardiac surgery: a multicentre cohort study

BACKGROUND

Whilst intraoperative hypotension is associated with postoperative acute kidney injury (AKI), the link between intraoperative hypotension and acute kidney disease (AKD), defined as continuing renal dysfunction for up to 3 months after exposure, has not yet been studied.

METHODS

We conducted a retrospective multicentre cohort study using data from noncardiac, non-obstetric surgery extracted from a US electronic health records database. Primary outcome was the association between intraoperative hypotension, at three MAP thresholds (≤75, ≤65, and ≤55 mm Hg), and the following two AKD subtypes: (i) persistent (initial AKI incidence within 7 days of surgery, with continuation between 8 and 90 days post-surgery) and (ii) delayed (renal impairment without AKI within 7 days, with AKI occurring between 8 and 90 days post-surgery). Secondary outcomes included healthcare resource utilisation for patients with either AKD subtype or no AKD.

RESULTS

A total of 112 912 surgeries qualified for the study. We observed a rate of 2.2% for delayed AKD and 0.6% for persistent AKD. Intraoperative hypotension was significantly associated with persistent AKD at MAP ≤55 mm Hg (hazard ratio 1.1; 95% confidence interval: 1.38-1.22; P<0.004). However, IOH was not significantly associated with delayed AKD across any of the MAP thresholds. Patients with delayed or persistent AKD had higher healthcare resource utilisation across both hospital and intensive care admissions, compared with patients with no AKD.

CONCLUSIONS

Intraoperative hypotension is associated with persistent but not delayed acute kidney disease. Both types of acute kidney disease appear to be associated with increased healthcare utilisation. Correction of intraoperative hypotension is a potential opportunity to decrease postoperative kidney injury and associated costs.

A web-based machine-learning algorithm predicting postoperative acute kidney injury after total knee arthroplasty

PURPOSE

Acute kidney injury (AKI) is a deleterious complication after total knee arthroplasty (TKA). The purposes of this study were to identify preoperative risk factors and develop a web-based prediction model for postoperative AKI, and assess how AKI affected the progression to ESRD.

METHOD

The study included 5757 patients treated in three tertiary teaching hospitals. The model was developed using data on 5302 patients from two hospitals and externally validated in 455 patients from the third hospital. Eighteen preoperative variables were collected and feature selection was performed. A gradient boosting machine (GBM) was used to predict AKI. A tenfold-stratified area under the curve (AUC) served as the metric for internal validation. Calibration was performed via isotonic regression and evaluated using a calibration plot. End-stage renal disease (ESRD) was followed up for an average of 41.7 months.

RESULTS

AKI develops in up to 10% of patients undergoing TKA, increasing the risk of progression to ESRD. The ESRD odds ratio of AKI patients (compared to non-AKI patients) was 9.8 (95% confidence interval 4.3-22.4). Six key predictors of postoperative AKI were selected: higher preoperative levels of creatinine in serum, the use of general anesthesia, male sex, a higher ASA class (> 3), use of a renin-angiotensin-aldosterone system inhibitor, and no use of tranexamic acid (all p < 0.001). The predictive performance of our model was good (area under the curve 0.78 [95% CI 0.74-0.81] in the developmental cohort and improved in the external validation cohort (0.89). Our model can be accessed at https://safetka.net .

CONCLUSIONS

A web-based predictive model for AKI after TKA was developed using a machine-learning algorithm featuring six preoperative variables. The model is simple and has been validated to improve both short- and long-term prognoses of TKA patients. Postoperative AKI may lead to ESRD, which surgeons should strive to avoid.

LEVEL OF EVIDENCE

Diagnostic level II.

Risk Factors and Effect of Acute Kidney Injury on Outcomes Following Total Hip and Knee Arthroplasty

BACKGROUND

Development of acute kidney injury (AKI) following primary total joint arthroplasty (TJA) is a potentially avoidable complication associated with negative outcomes including discharge to facilities and mortality. Few studies have identified modifiable risk factors or strategies that the surgeon may use to reduce this risk.

METHODS

We identified all patients undergoing primary TJA at a single hospital from 2005 to 2017, and collected patient demographics, comorbidities, short-term outcomes, as well as perioperative laboratory results. We defined AKI as an increase in creatinine levels by 50% or 0.3 points. We compared demographics, comorbidities, and outcomes between patients who developed AKI and those who did not. Multivariate regressions identified the independent effect of AKI on outcomes. A stochastic gradient boosting model was constructed to predict AKI.

RESULTS

In total, 814 (3.9%) of 20,800 patients developed AKI. AKI independently increased length of stay by 0.26 days (95% confidence interval [CI] 0.14-0.38, P < .001), in-hospital complication risk (odds ratio = 1.73, 95% CI 1.45-2.07, P < .001), and discharge to facility risk (odds ratio = 1.26, 95% CI 1.05-1.53, P = .012). Forty-one predictive variables were included in the predictive model, with important potentially modifiable variables including body mass index, perioperative hemoglobin levels, surgery duration, and operative fluids administered. The final predictive model demonstrated excellent performance with a c-statistic of 0.967.

CONCLUSION

Our results confirm that AKI has adverse effects on outcome metrics including length of stay, discharge, and complications. Although many risk factors are nonmodifiable, maintaining adequate renal perfusion through optimizing preoperative hemoglobin, sufficient fluid resuscitation, and reducing blood loss, such as through the use of tranexamic acid, may aid in mitigating this risk.

Do early non-steroidal anti-inflammatory drugs for analgesia worsen acute kidney injury in critically ill trauma patients? An inverse probability of treatment weighted analysis

BACKGROUND

Administration of nonsteroidal anti-inflammatory drugs (NSAIDs) for acute posttraumatic analgesia is increasing in popularity as an alternative to opioids despite reservations regarding its potential impact on the development of acute kidney injury (AKI). We hypothesized that early NSAID administration for analgesia would be associated with worsened renal function in severely injured trauma patients.

METHODS

A retrospective cohort study of severely injured adult (≥16 years) patients admitted to the intensive care unit with ≥1 rib fracture between 2010 and 2017 was performed. The early NSAID group was defined by receipt of one or more doses of NSAID within the first 48 hours of hospitalization. Acute kidney injury diagnosis and staging were defined by the Kidney Disease Improving Global Outcomes Guidelines. The primary outcome was a composite measure of two outcomes within the first week of hospitalization: (1) AKI progression (increase in AKI stage from arrival) or (2) death. Secondary outcomes included AKI progression, AKI improvement, AKI duration, and mortality. Inverse propensity of treatment weights were generated using clinically sound covariates suspected to be associated with the decision to give early NSAIDs and the primary or secondary outcomes. Multivariable analyses were performed adjusting for inverse propensity of treatment weights, covariates, and length of stay.

RESULTS

Of 2,340 patients, 268 (11%) were administered early NSAIDs. When compared with the control group, patients who received early NSAIDs were less severely injured. Renal outcomes were worse in the control group. Standardized mean differences were minimal after weighting. On multivariable analysis, administration of early NSAIDs was not associated with worsened renal outcomes or increased mortality.

CONCLUSION

Although only 11% of patients received early NSAIDs after trauma for analgesia, early NSAID exposure was not associated with increased AKI progression, decreased AKI improvement, prolonged duration, or increased mortality. Given the lack of evidence showing harm, early NSAIDs for analgesia may be underused for severely injured patients.

LEVEL OF EVIDENCE

Prognostic, level III, Therapeutic, level IV.

Determining the risk of acute kidney injury in patients who underwent total joint replacement: A retrospective study

OBJECTIVES

Total joint replacement (TJR) is a commonly performed procedure worldwide, and postoperative acute kidney injury (AKI) is one of the complications that determine the overall prognosis in various surgical settings. We aimed to identify the risk of AKI after TJR (primary and revision) and determine the factors associated with postoperative AKI.

METHODS

We performed a retrospective study of 1068 patients (>18 years) who underwent TJR between 2014 and 2019 at a tertiary medical center. Patients' demographic, clinical, and laboratory data were reviewed.

RESULTS

A total of 1068 patients were included in this study [mean age, 60.5 ± 13 years; 260 men (24.3%); 808 women (75.7%)]. A total of 962 patients (90.1%) underwent primary joint replacement (PJR) and 106 underwent joint revision (9.9%). Sixty-six patients (6.2%) had postoperative AKI. Primary total hip replacement patients had a lower risk of AKI than patients with other types of TJR (3.0%; p = 0.024). The factors associated with AKI (adjusting for known confounders) included male gender [adjusted odds ratio (AOR): 1.751; 95% confidence interval (CI): 1.01-3.03; p = 0.046], diabetes mellitus (DM) [AOR: 2.806; 95% CI: 1.687-5.023; p ≤ 0.001], hypertension (HTN) [AOR: 1.751; 95% CI: 1.159-3.442; p = 0.013], and the use of vancomycin as a prophylactic antibiotic [AOR: 1.691; 95% CI: 1.1-2.913; p = 0.050]. Chronic kidney disease (CKD) [AOR: 1.00; 95% CI: 0.432-2.27; p = 0.981] was not found to be a significant risk factor.

CONCLUSION

In this study, the risk of preoperative AKI in patients who underwent TJR was 6.2%. Male gender, preoperative comorbidities such as DM and HTN, and preoperative use of vancomycin were associated with increased risk of postoperative AKI.

Strategies to Reduce Perioperative Nephrotoxicity

Postoperative acute kidney injury (AKI) is a common complication of surgery that is associated with significant adverse outcomes, including increased morbidity and mortality. The perioperative burden of AKI risk factors is complex and potentially large, including high-risk nephrotoxic medications, hypotension, hypovolemia, radiologic contrast, anemia, and surgery-specific factors. Understanding the pathogenesis, risk factors, and potential cumulative impact of perioperative nephrotoxic exposures is particularly important in the prevention and reduction of perioperative AKI. This review outlines the possible strategies to reduce perioperative nephrotoxicity and the development of postoperative AKI.

Re-evaluating the utility of routine postoperative laboratory tests after primary total knee arthroplasty

BACKGROUND

While advancements in surgery and reduced complication rates have made total knee arthroplasty (TKA) one of the most successful and cost-effective procedures in orthopaedic surgery, routine postoperative laboratory tests are still being ordered without evidence as to their necessity. With expansion of the bundled payment models, there may exist an opportunity to cut overall costs while maintaining quality of care by eliminating unnecessary interventions. The objective of this study was to examine the utility of routine postoperative laboratory tests in TKA.

METHODS

A retrospective review of 319 TKAs performed at a single institution over a 2-year period was performed. The primary outcomes were the rates of acute blood loss anemia requiring transfusion, acute kidney injury (AKI), electrolyte abnormalities, and 90-day emergency department visits and readmissions. Multivariate logistic regression analysis was also performed to identify the risk factors associated with abnormal laboratory values.

RESULTS

89 patients (27.9%) had abnormal postoperative laboratory results, of which 78% were exclusively due to electrolyte (sodium or potassium) abnormalities. The rates of AKI and blood transfusion were 3.8% and 1% respectively. Factors associated with electrolyte abnormalities were abnormal baseline electrolyte levels (p = 0.002 and = 0.006 for sodium and potassium respectively) and anemia (p = 0.049). Factors associated with blood transfusion were ASA score ≥3, preoperative anemia, and no tranexamic acid use. Factors associated with AKI were chronic kidney disease or having at least two of the following: age >65 years, BMI> 35, ASA score ≥3, diabetes, heart disease, and/or anemia. Laboratory results did not change the course of care in 305 of 319 patients (95.6%). There was no increased risk for 90-days ED visits or readmissions with abnormal laboratory values (p = 0.356).

CONCLUSION

With increasing pressure for cost containment in an era of bundled payment models, the very low rate of laboratory associated interventions suggest that routine postoperative laboratory tests is not justified. Obtaining laboratory after primary, unilateral TKA should be driven by patients' risk factors.

Acute kidney injury after primary total hip arthroplasty: a risk multiplier for complication, mortality, and healthcare utilization

Objective

To assess whether acute kidney injury (AKI) is associated with more complications and higher healthcare utilization in people undergoing primary total hip arthroplasty (THA).

Methods

Using a retrospective cohort study design, we performed multivariable-adjusted logistic regression of the 1998–2014 US National Inpatient Sample data to assess the association of AKI with complications (infection, transfusion, revision, and mortality) and healthcare utilization (total hospital charges, discharge to a rehabilitation facility, length of hospital stay) post-THA. We calculated the odds ratio (OR) and 95% confidence intervals (CI).

Results

Adjusted for age, gender, race, income, underlying diagnosis, medical comorbidity, and the insurance payer, AKI in people who underwent primary THA was associated with significantly higher OR (95% CI) of (1) implant infection, 2.34 (95% CI, 1.87, 2.93); (2) transfusion, 2.46 (95% CI, 2.37, 2.56); (3) revision, 2.54 (95% CI, 2.16, 2.98); (4) death, 8.52 (95% CI, 7.47, 9.73); (5) total hospital charges above the median, 2.29 (95% CI, 1.99, 2.65); (6) discharge to a rehabilitation facility, 2.11 (95% CI, 2.02, 2.20); and (7) hospital stay > 3 days, 4.34 (95% CI, 4.16, 4.53).

Conclusion

Quality improvement initiatives with optimization of the peri-operative care to reduce AKI and subsequently AKI-associated complications and healthcare utilization are needed. Mechanisms of AKI-associated post-THA complications need further examination.

Incidence of chronic kidney disease in patients undergoing arthroplasty: A systematic review of the literature

Patients undergoing arthroplasty are exposed to different interventions that can lead to renal dysfunction. There is abundant evidence of the incidence and factors associated with acute kidney injury (AKI); however, the incidence and the factors associated with chronic kidney disease (CKD) are not clear. The objective of this study is to determine the incidence and associated factors in arthroplasty patients. A systematic review of the literature was carried out following the recommendations of PRISMA and the Cochrane Collaboration (PROSPERO Protocol CRD42018075929). The search was carried out in Medline, Embase, Cochrane and LILACS. No language or date limits were set. Observational studies were included: cases and controls, and cohorts. The revision of titles and abstracts and the reading of the full texts was performed in a paired manner. The quality of the evidence was evaluated with the Newcastle-Ottawa tool. The initial search found 1279 titles and abstracts. We excluded 115 duplicates, and 1153 in the reading of titles and abstracts. Three articles met the inclusion criteria and were of acceptable quality. The incidence of severe CKD after hip or knee arthroplasty was 1.2% at 1 year up to 6.5% at 9 years. The evidence of the incidence and risk factors associated with CKD in patients undergoing arthroplasty is very scarce and heterogeneous. Further primary studies are required in order to have more valid and trustable results.

Cyclooxygenase 2 inhibition slows disease progression and improves the altered renal lipid mediator profile in the Pkd2WS25/- mouse model of autosomal dominant polycystic kidney disease

BACKGROUND

Increased levels of cyclooxygenase (COX) derived oxylipins is the earliest and most consistent alteration in the renal oxylipin profile in diverse models of cystic kidney diseases. Therefore, we examined whether a COX2 inhibitor would reduce disease progression in the Pkd2WS25/- mouse model of autosomal dominant polycystic kidney disease (ADPKD).

METHODS

Weanling normal and diseased male Pkd2 mice were provided diets that provided 0 or 50 mg celecoxib/kg body weight/day, for 13 weeks. Renal disease and function were assessed by histomorphometric analysis of renal cysts and measurement of serum creatinine and urea nitrogen (SUN) levels. Targeted lipidomic analysis of renal oxylipins was performed by HPLC-MS/MS.

RESULTS

Diseased mice had significant cyst involvement and reduced renal function as indicated by elevated serum creatinine and SUN. Celecoxib reduced cyst area by 48%, cyst volume by 70%, and serum creatinine and SUN by 20% and 16%, respectively. Consistent with our previous studies, 8 of the 11 COX derived oxylipins were higher in diseased kidneys. In addition, 24 of 33 lipoxygenase (LOX) derived oxylipins and 7 of 16 cytochrome P450 (CYP) derived oxylipins were lower in diseased kidneys. Celecoxib reduced total and five of the eight individual elevated COX oxylipins and increased 5 of 24 LOX and 5 of 7 CYP oxylipins that were reduced by disease.

CONCLUSIONS

COX2 inhibition ameliorates disease progression, improves renal function and improves the altered oxylipins in Pkd2 mice. This represents a potential new approach for treatment of ADPKD, a disorder for which no effective treatment currently exists.

Effect of Anesthetic Technique on the Occurrence of Acute Kidney Injury after Total Knee Arthroplasty

Recent studies have reported the advantages of spinal anesthesia over general anesthesia in orthopedic patients. However, little is known about the relationship between acute kidney injury (AKI) after total knee arthroplasty (TKA) and anesthetic technique. This study aimed to identify the influence of anesthetic technique on AKI in TKA patients. We also evaluated whether the choice of anesthetic technique affected other clinical outcomes. We retrospectively reviewed medical records of patients who underwent TKA between January 2008 and August 2016. Perioperative data were obtained and analyzed. To reduce the influence of potential confounding factors, propensity score (PS) analysis was performed. A total of 2809 patients and 2987 cases of TKA were included in this study. A crude analysis of the total set demonstrated a significantly lower risk of AKI in the spinal anesthesia group. After PS matching, the spinal anesthesia group showed a tendency for reduced AKI, without statistical significance. Furthermore, the spinal anesthesia group showed a lower risk of pulmonary and vascular complications, and shortened hospital stay after PS matching. In TKA patients, spinal anesthesia had a tendency to reduce AKI. Moreover, spinal anesthesia not only reduced vascular and pulmonary complications, but also shortened hospital stay.

Routine Postoperative Laboratory Tests Are Not Necessary After Primary Total Hip Arthroplasty

BACKGROUND

Postoperative laboratory testing has been used routinely for patients undergoing total hip arthroplasty (THA). However, with modern-day improvements in perioperative care pathways, it is unclear whether this practice remains justified. The purpose of this study was to assess the utility of routine postoperative laboratory tests in primary THA.

METHODS

The electronic medical records of 351 patients who underwent primary, unilateral THA between 2015 and 2017 were retrospectively reviewed. The primary outcomes were the rates of acute blood loss anemia requiring transfusion, acute kidney injury (AKI), electrolyte abnormalities, and 90-day emergency department visits or readmissions. Multivariate logistic regression analysis was also performed to identify the risk factors associated with abnormal laboratory values.

RESULTS

Seventy-four patients (21%) had abnormal postoperative laboratory results, of which 82.4% were exclusively due to electrolyte (sodium or potassium) abnormalities. Factors associated with electrolyte abnormalities were abnormal baseline electrolyte levels (P < .001 and P = .013 for sodium and potassium, respectively), diabetes (P = .007), and lack of tranexamic acid use (P < .01). The rates of AKI and blood transfusion were 2.0% and 2.3%, respectively. Factors associated with blood transfusion were higher American Society of Anesthesiologists class and intraoperative blood loss ≥250 mL combined with either preoperative anemia or lack of tranexamic acid use. Factors associated with AKI were higher American Society of Anesthesiologists class and diabetes. Laboratory results did not change the standard course of care in 338 of 351 patients (96%). Abnormal laboratory values were not associated with increased length of stay (P = .228) or emergency department visits/readmissions (P = .21).

CONCLUSION

This study provides evidence that routine postoperative laboratory testing is not necessary in modern-day primary, unilateral THA. Instead, the decision to obtain laboratory tests after surgery should be driven by patients' risk factors.

Renal complications of anaesthesia

Peri-operative acute kidney injury is common, accounting for 30-40% of all in-hospital cases of acute kidney injury. It is associated with clinically significant morbidity and mortality even with what was hitherto regarded as relatively trivial increases in serum creatinine, and carries over a 12-fold relative risk of death following major abdominal surgery. Comorbid conditions such as diabetes, hypertension, liver disease and particularly pre-existing chronic kidney disease, as well as the type and urgency of surgery, are major risk factors for the development of postoperative acute kidney injury. As yet, there are no specific treatment options for the injured kidney, although there are several modifiable risk factors of which the anaesthetist should be aware. As well as the avoidance of potential nephrotoxins and appropriate volume balance, optimal anaesthetic management should aim to reduce the risk of postoperative renal complications. This may include careful ventilatory management and blood pressure control, as well as appropriate analgesic strategies. The choice of anaesthetic agent may also influence renal outcomes. Rather than concentrate on the classical management of acute kidney injury, this review focuses on the potential development of acute kidney injury peri-operatively, and the means by which this may be ameliorated.

Acute Kidney Injury in Patients Undergoing Total Hip Arthroplasty: A Systematic Review and Meta-Analysis

Background: The number of total hip arthroplasties (THA) performed across the world is growing rapidly. We performed this meta-analysis to evaluate the incidence of acute kidney injury (AKI) in patients undergoing THA. Methods: A literature search was performed using MEDLINE, EMBASE and Cochrane Database from inception until July 2018 to identify studies assessing the incidence of AKI (using standard AKI definitions of RIFLE, AKIN, and KDIGO classifications) in patients undergoing THA. We applied a random-effects model to estimate the incidence of AKI. The protocol for this meta-analysis is registered with PROSPERO (no. CRD42018101928). Results: Seventeen cohort studies with a total of 24,158 patients undergoing THA were enrolled. Overall, the pooled estimated incidence rates of AKI and severe AKI requiring dialysis following THA were 6.3% (95% CI: 3.8%–10.2%) and 0.5% (95% CI: 0.1%–2.3%). Subgroup analysis based on the countries by continent was performed and demonstrated the pooled estimated incidence of AKI following THA of 9.2% (95% CI: 5.6%–14.8%) in Asia, 8.1% (95% CI: 4.9%–13.2%) in Australia, 7.4% (95% CI: 3.2%–16.3%) in Europe, and 2.8% (95% CI: 1.2%–17.0%) in North America. Meta-regression of all included studies showed significant negative correlation between incidence of AKI following THA and study year (slope = −0.37, p <0.001). There was no publication bias as assessed by the funnel plot and Egger’s regression asymmetry test with p = 0.13 for the incidence of AKI in patients undergoing THA. Conclusion: The overall estimated incidence rates of AKI and severe AKI requiring dialysis in patients undergoing THA are 6.3% and 0.5%, respectively. There has been potential improvement in AKI incidence for patients undergoing THA over time.

Acute Kidney Injury Following Failed Total Hip and Knee Arthroplasty

BACKGROUND

Acute kidney injury (AKI) can complicate primary total joint arthroplasty (TJA) of the hip and knee, although the incidence of AKI following revision TJA including prosthetic joint infection (PJI) is poorly defined. We assessed the incidence and risk factors for AKI following revision TJA including surgical treatment of PJI with placement of an antibiotic-loaded cement (ALC) spacer.

METHODS

We retrospectively reviewed 3218 consecutive failed TJAs. Patients with aseptic failure were compared to those with PJI. AKI was determined by RIFLE creatinine criteria. PJIs treated with placement of ALC were compared to PJIs without. Risk factors for AKI were determined by multivariable analysis within the whole group and within those with PJI.

RESULTS

AKI developed in 3.4% of 2147 patients revised for aseptic reasons and in 45% of 281 with PJI, including 29% of 197 receiving an ALC and 82% of 84 patients treated with other procedures. By multivariable analysis, age, surgery for PJI, total number of surgeries, and estimated GFR 60-90 compared to >90 cc/min/1.73 m² were significantly associated with AKI in the whole cohort. Among PJI patients, age, Charlson comorbidity index, and reimplantation surgery were associated with AKI by multivariable analysis. No differences were found between patients with PJI treated with or without ALC. No modifiable factors were found.

CONCLUSION

AKI develops following aseptic revision TJA at a rate similar to primary TJA, but at a significantly higher rate following surgery for PJI with or without placement of ALC.

Novel renal markers for the assessment of renal integrity in patients undergoing knee arthroplasty - a pilot study

Background

The feasibility of novel kidney injury biomarkers in consecutive patients having total knee arthroplasty with local infiltration analgesia was evaluated.

Methods

We enrolled 30 patients scheduled for elective unilateral total knee arthroplasty. Paired plasma and urine samples were taken before surgery and at 4 h, 24 h and 48 h after surgery to measure creatinine, cystatin C, neutrophil gelatinase associated lipocalin, kidney injury molecule-1, interleukin-18 and liver-type fatty acid-binding protein.

Results

At baseline, 13 subjects had normal kidney function, 15 had mild and two had moderate kidney failure evaluated by calculated glomerular filtration rate. None of the subjects had all measured novel renal markers below proposed cut-off concentrations. Altogether 28/30 subjects had one (n = 3), two (n = 7) or three (n = 18) plasma neutrophil gelatinase associated lipocalin values above normal. In seven of these 28 subjects plasma creatinine, calculated glomerular filtration rate and plasma cystatin C were within the reference values. Five subjects had a low urine output, < 0.5 mL/h, indicating transient acute kidney injury, four of these had high plasma neutrophil gelatinase associated lipocalin and one high plasma cystatin C.

Conclusions

In the present study plasma neutrophil gelatinase associated lipocalin was elevated in most subjects with total knee arthroplasty and local infiltration analgesia as a marker of possible renal proximal tubular injury. Five subjects had transient low urine output, but none developed renal deterioration requiring treatment.

Staggered Rather Than Staged or Simultaneous Surgical Strategy May Reduce the Risk of Acute Kidney Injury in Patients Undergoing Bilateral TKA

BACKGROUND

The strategy for bilateral total knee arthroplasty (TKA) depends on the timing of surgery for each knee. The purpose of this study was to determine whether the type of surgical strategy for bilateral TKA (staggered, staged, or simultaneous) influences the incidence of acute kidney injury (AKI) and related complications.

METHODS

Enrolled patients from a single tertiary teaching hospital were divided into 3 groups according to the surgical strategy for bilateral TKA: staggered (≤7 days between the first and second procedure; n = 368), staged (8 days to 1 year between the first and second procedure; n = 265), or simultaneous (n = 820). The incidence of AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria was assessed. The rates of major postoperative complications, major adverse cardiovascular and cerebral events, intensive care unit (ICU) admissions, and mortality were also evaluated. To reduce the influence of possible confounding factors, inverse probability of treatment weighting based on propensity-score analysis was used.

RESULTS

The primary outcome was the incidence of AKI according to surgical strategy. The staggered group had a lower rate of AKI compared with the other 2 groups (p < 0.001): 2.4% (9 of 368 patients), 6.0% (16 of 265), and 11.2% (92 of 820) in the staggered, staged, and simultaneous groups, respectively.

CONCLUSIONS

The type of bilateral TKA strategy was an independent risk factor for the development of AKI. The assessment of additional risk factors for the development of AKI is essential before deciding on surgical strategy.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Acute kidney injury following implementation of an enhanced recovery after surgery (ERAS) protocol in colorectal surgery

PURPOSE

Fluid management within Enhanced Recovery After Surgery (ERAS) protocols is designed to maintain a euvolemic state avoiding the negative sequelae of hypervolemia or hypovolemia. We sought to determine the effect of a recent ERAS protocol implementation on kidney function and on the incidence of postoperative acute kidney injury (AKI).

METHODS

A total of 132 elective colorectal resections performed using our ERAS protocol were compared to a propensity-matched group prior to ERAS implementation. Fluid balance, urine output, creatinine, and blood urea nitrogen (BUN) were recorded for all patients, and the incidence of AKI was determined according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria.

RESULTS

Implementation of our ERAS protocol decreased average postoperative length of hospital stay (5.5 vs 7.7 days, p < 0.0001) and time to return of bowel function (2.5 vs 4.1 days, p < 0.0001). The rate of postoperative AKI increased following implementation of the protocol (11.4 vs 2.3%, p < 0.0001). However, by the time of discharge, the average creatinine of ERAS patients who had experienced AKI had returned to their preoperative baseline values (p = 0.9037). Significant univariate predictors of AKI in ERAS patients were longer operative times (p < 0.01) and the diagnosis of diverticulitis (p < 0.01). Within our ERAS patients, AKI was associated with a prolonged postoperative length of hospital stay (p < 0.01).

CONCLUSIONS

Despite the proven benefits of the Enhanced Recovery After Surgery (ERAS) protocols, care should be taken during protocol implementation to monitor for and to prevent acute kidney injury.

The Incidence and Risk Factors of Acute Kidney Disease after Total Knee Arthroplasty with Early Postoperative Volume Supplement

Background

Etiology of acute kidney disease (AKD) after total knee arthroplasty (TKA) was considered as multifactorial. However, the role of early postoperative volume supplement in AKD rate has not been investigated. The purpose of this study was to evaluate the incidence and risk factors of AKD in patients with early volume supplement following TKA.

Methods

This was a retrospective study with 458 patients who underwent unilateral TKA. All the patients received 6% tetrastarch, 7.5ml/kg, early in the postoperative period. Postoperative AKD was defined as the postoperative creatinine level ≥ 1.5 times compared with preoperative data. Potential variables associated with AKD were analyzed by multivariate logistic regression model to identify the AKD risk factors in TKA patients after early postoperative volume supplement.

Results

The AKD rate was 3.3% (15 patients) in all patients. Age (OR = 1.09; P = .031) and coronary artery disease (CAD) (OR = 3.63; P = .034) were associated with increased risk of development of postoperative AKD. Other comorbidities as hypertension, diabetes, and CKD were not statistically significant risk factors.

Conclusion

Our study demonstrated that age and CAD were independent risk factors of AKD in TKA patients. However, the common risk factors as hypertension, diabetes, and CKD were not significantly associated with AKD after TKA if early postoperative supplement of tetrastarch is administered.

Randomized controlled trial of intra-articular ketorolac on pain and inflammation after minor arthroscopic knee surgery

BACKGROUND

Ketorolac is an effective non-steroidal anti-inflammatory drug, commonly used with local anaesthetics as part of local infiltration analgesia protocols following orthopaedic surgery. However, systemic uptake and drug action may be the major mechanism after local infiltration. The aims of this project were to study the effects of a small, systemically ineffective dose of ketorolac given intra-articularly for post-operative pain and also to study synovial inflammatory biomarkers. We investigated whether ketorolac affects pro-inflammatory biomarkers in an in vitro model, as well.

METHODS

In this placebo-controlled, blind, randomized study, we analysed intra-articular ketorolac (5 mg) in ambulatory minor knee surgery patients with moderate or severe pain (n = 44). We assessed post-operative pain intensity (n = 44) and analysed microdialysis samples taken from knee synovial tissue every 20 min (n = 34). We also tested cyclooxygenase-independent effects of ketorolac in synovial cells stimulated by prostaglandin E₂ and chondroitin sulphate in vitro.

RESULTS

Intra-articular ketorolac (5 mg) administration did not reduce pain or synovial pro-inflammatory cytokines CXCL1, IL-8, and MCP-1, 0-120 min after knee arthroscopy. Female gender was a risk factor for moderate or severe pain (relative risk 1.45, 95% confidence interval 1.04-2.01). Paradoxically, ketorolac increased the release of CXCL1 and IL-8 in prostaglandin E₂ and chondroitin sulphate-stimulated synovial cells in vitro.

CONCLUSION

Ketorolac prescribed at a low dose intra-articularly does not produce any detectable analgesic effect after minor knee surgery.

Cost and determinants of acute kidney injury after elective primary total joint arthroplasty

Background

Acute kidney injury (AKI) is a serious complication after major surgery, which may lead to increased morbidity and mortality. The aim of this study was to identify cost and determinants of AKI after total joint arthroplasty.

Methods

A retrospective case-controlled study was conducted with 1719 primary elective total hip or knee replacements performed from January 2004 through September 2015 at an urban teaching hospital. Patients who developed AKI were matched in a 1:3 ratio with those in a control group who did not develop AKI based on age, sex, race, operated joint, and comorbidities including hypertension and diabetes. Increased postoperative serum creatinine was considered indicative of AKI.

Results

Fifty-four patients (3.1%) had AKI that was significantly associated with increased length of hospital stay (8.07 days) compared with that of the control group (4.50 days, P < .0001) and incurred significantly higher hospital charges ($224,533) than those of the control group ($142,753, P < .0001). We identified high body mass index, undergoing bilateral surgery in one session, high estimated blood loss, and longer duration of surgery as significant risk factors for AKI in univariate analysis. Elevated preoperative creatinine, large postoperative drop in hemoglobin, and high American Society of Anesthesiologists physical status scores were significant independent predictors of AKI in multivariate analysis.

Conclusions

Health-care providers and patients should work together to manage risk factors and to lower the risk of morbidity and mortality, longer in-hospital stay, and high associated costs of AKI.

Reducing Hypotension and Acute Kidney Injury in the Elective Total Joint Arthroplasty Population: A Multi-Disciplinary Approach

BACKGROUND

When critically analyzing our hospital system's rate of hypotension and acute kidney injury (AKI) after total joint arthroplasty, our incidence rates (14.54%, 6.02%) were much higher than our peers (7.17%, 2.03%) and national rates (2.0%, 3.3%). We present a multi-disciplinary management intervention that aimed to decrease overall complication rates.

METHOD

A multi-disciplinary team implemented a protocol at our suburban hospital to limit complication rates after joint replacement surgery. Hypotension, AKI, length of stay (LOS), re-admission rates, and mortality rates were compared before the protocol was implemented, after protocol implementation, and after protocol integration into our EMR (electronic medical record).

RESULTS

In total, 1233 patients over 36 months were followed. Hypotension rates after protocol implementation into EMR (group 3) were significantly lower than rates before the protocol (group 1) (P = .002), with rates after protocol implementation without EMR (group 2) trending toward a significant decrease from group 1 (P = .064). AKI rates in group 3 were significantly lower than group 1 (P = .000) and group 2 (P = .006). No difference was seen in hypotension rates between group 2 and 3 (P = .792) or AKI rates between group 1 and 2 (P = .533). Finally, no significant difference was seen between groups in LOS (P = .560), re-admission rates (P = .378), and mortality rates (all 0.0%).

CONCLUSION

By implementing a comprehensive electronic protocol consisting of pre-operative risk stratification, multi-disciplinary medical optimization, and an evolving post-operative management plan, significant decreases in hypotension and AKI can be seen.

Oral Multimodal Analgesia for Total Joint Arthroplasty

BACKGROUND

Oral multimodal analgesia for hip and knee arthroplasty is increasingly used as part of enhanced recovery protocols designed to minimize early postoperative pain and to facilitate early discharge, while minimizing undesirable side effects related to single-agent opioid administration.

METHODS

This article is a review of previously published data evaluating the use of various oral medications in the management of postoperative pain after lower extremity arthroplasty and was presented as part of a symposium at the November 2016 AAHKS Annual Meeting.

RESULTS

Multimodal analgesia has been shown to reduce opioid consumption and side effects, with a positive effect on both early and longer term outcomes for hip and knee arthroplasty patients. Medications directed at multiple points on the pain cascade minimize pain by different mechanisms. Suggested dosing regimens are proposed.

CONCLUSION

Oral multimodal analgesia incorporating a combination of opioid and nonopioid analgesics, selective and nonselective anti-inflammatory drugs, acetaminophen, and gabapentinoids are recommended as a part of a pre-emptive approach to pain management in patients undergoing hip or knee arthroplasty. Reduction of opioid consumption and minimization of side effects are primary outcomes, and prevention of chronic pain can positively affect long-term results.

Early postoperative albumin level following total knee arthroplasty is associated with acute kidney injury: A retrospective analysis of 1309 consecutive patients based on kidney disease improving global outcomes criteria

Hypoalbuminemia has been reported to be an independent risk factor for acute kidney injury (AKI). However, little is known about the relationship between the albumin level and the incidence of AKI in patients undergoing total knee arthroplasty (TKA). The aim of our study was to assess incidence and risk factors for AKI and to evaluate the relationship between albumin level and AKI following TKA.The study included a retrospective review of medical records of 1309 consecutive patients who underwent TKA between January 2008 and December 2014. The patients were divided into 2 groups according to the lowest serum albumin level within 2 postoperative days (POD2_alb level < 3.0 g/dL vs ≥3.0 g/dL). Multivariate logistic regression analysis was used to assess risk factors for AKI. A comparison of incidence of AKI, hospital stay, and overall mortality in the 2 groups was performed using propensity score analysis.Of 1309 patients, 57 (4.4%) developed AKI based on Kidney Disease Improving Global Outcomes criteria. Factors associated with AKI included age (odds ratio [OR] 1.05; 95% confidence interval [CI] 1.01-1.09; P = 0.030), diabetes (OR 3.12; 95% CI 1.65-5.89; P < 0.001), uric acid (OR 1.51; 95% CI 1.26-1.82; P < 0.001), beta blocker use (OR 2.65; 95% CI 1.48-4.73; P = 0.001), diuretics (OR 16.42; 95% CI 3.08-87.68; P = 0.001), and POD2_alb level < 3.0 g/dL (OR 1.92; 95% CI 1.09-3.37; P = 0.023). After propensity score analysis, POD2_alb level<3.0 g/dL was associated with AKI occurrence (OR 1.82; 95% CI 1.03-3.24, P = 0.041) and longer hospital stay (P = 0.001).In this study, we demonstrated that POD2_alb level<3.0 g/dL was an independent risk factor for AKI and lengthened hospital stay in patients undergoing TKA.

Salidroside suppresses solar ultraviolet-induced skin inflammation by targeting cyclooxygenase-2

Solar ultraviolet (SUV) irradiation causes skin disorders such as inflammation, photoaging, and carcinogenesis. Cyclooxygenase-2 (COX-2) plays a key role in SUV-induced skin inflammation, and targeting COX-2 may be a strategy to prevent skin disorders. In this study, we found that the expression of COX-2, phosphorylation of p38 or JNKs were increased in human solar dermatitis tissues and SUV-irradiated human skin keratinocyte HaCaT cells and mouse epidermal JB6 Cl41 cells. Knocking down COX-2 inhibited the production of prostaglandin E2 (PGE2), the phosphorylation of p38 or JNKs in SUV-irradiated cells, which indicated that COX-2 is not only the key enzyme for PGs synthesis, but also an upstream regulator of p38 or JNKs after SUV irradiation. The virtual ligand screening assay was used to search for natural drugs in the Chinese Medicine Database, and indicated that salidroside might be a COX-2 inhibitor. Molecule modeling indicated that salidroside can directly bind with COX-2, which was proved by in vitro pull-down binding assay. Ex vivo studies showed that salidroside has no toxicity to cells, and inhibits the production of PGE2, phosphorylation of p38 or JNKs, and secretion of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) caused by SUV irradiation. In vivo studies demonstrated that salidroside attenuates the skin inflammation induced by SUV. In brief, our data provided the evidences for the protective role of salidroside against SUV-induced inflammation by targeting COX-2, and salidroside might be a promising drug for the treatment of SUV-induced skin inflammation.