Is Immediate Postoperative Radiograph Necessary Following Robotic-Assisted Total Knee Arthroplasty?

Background The necessity of immediate postoperative radiographs following total knee arthroplasty (TKA) has long been debated. With the increasing use of robotic-assisted TKA (RTKA), and thus more precise implant placement, the need for immediate postoperative radiographs to determine implant positioning may be unnecessary. We sought to evaluate implant position on the immediate postoperative radiographs following RTKA to determine their necessity. Methods A retrospective review of 150 RTKAs was performed. The posterior slope for all TKAs were recorded based on the preoperative three-dimensional template. Additionally, two independent trained researchers (JG/LB) each measured the posterior slope of the postoperative day 0 (POD0) radiograph and postoperative 2 week radiograph. The difference in posterior slope measurement between template and POD0, between template and 2 weeks, and between POD0 and 2 weeks was calculated. Results Of the 150 TKAs performed, there were no periprosthetic fractures found on the POD0 radiograph. The mean difference between the templated posterior slope and measured posterior slope on POD0 was 0.04 degrees (SD 1.01)(p = 0.615). There was a weak correlation between the two values (rs [95% CI] 0.38 [0.21, 0.53]). When comparing the template to the 2-week radiographs, there was a mean difference of 0.02 degrees (SD 0.48)(p = 0.556).  However, there was a moderate to strong correlation noted (rs [95% CI] 0.71 [0.61, 0.79]). Comparison of the mean posterior slope from POD0 radiograph to that of 2 week radiograph showed a mean difference of 0.06 degrees (SD 1.0)(p = 0.427). A weak correlation was found between these two values (rs [95% CI] 0.43 [0.26, 0.56]). Conclusions Given the accuracy and precision of RTKA, along with the ability to decrease cost and radiation, immediate postoperative radiograph may be unnecessary, when pertaining to the uncomplicated RTKA. However, if there is concern for intraoperative fracture, long stems placed in a revision arthroplasty or other intraoperative complications then postoperative radiographs are encouraged. .

How to Estimate Femoral Stem Anteversion During Direct Anterior Approach Total Hip Arthroplasty.

Background: There are various traditional landmarks used to estimate the femoral component version, yet none are widely accepted by direct anterior surgeons. The purpose of this study was to compare bony landmarks easily accessible to direct anterior surgeons and to estimate which one provides the best estimate of femoral component anteversion. Methods: A computed tomography database was used to identify 736 left entire-femur computed tomography scans. Seven visible anatomic landmarks were identified using a computer model in which a 45° virtual neck resection was made at 10 mm above the lesser trochanter. Thirteen axes, to reference the femoral stem position, were created between the 7 landmarks. Means and standard deviations (SDs) of angles between each axis and the transepicondylar axis (TEA) were compared for their precision. Results: The traditional lesser trochanter predicted anteversion from the TEA was 34.1° (SD 9.7°). Predicted anteversion from the TEA was 3.3° (SD 8.1°) when aligned from the center of the canal to the middle of the medial calcar; 14.0° (SD 8.1°) from the center of the canal to the anterior 1/3 of the medial calcar; and 24.8° (SD 8.5°) from the center of the canal to the most anterior point on the medial calcar. Conclusions: Compared to the lesser trochanter, 7 axes were more precise (lower SD) when predicting the version. Estimating the femoral component position, via simulated data, using 3 points along the medial calcar is a relatively precise and easily accessible tool for surgeons.

Patient-Specific Venous Thromboembolic Event Prophylaxis in Total Joint Arthroplasty - Literature-Supported Guidelines.

Following total joint arthroplasty (TJA), venous thromboembolic events (VTE) are a known complication that may result in increased hospitalization cost as well as morbidity. Numerous investigations have documented patient-specific factors that place an individual at increased risk of VTE after TJA. Potential risk factors for VTE include genetic predisposition, history of a prior VTE event, revision surgery and patient comorbidity factors. The American Academy of Orthopedic Surgeons and The American College of Chest Physicians have both provided recommendations for VTE prophylaxis after orthopedic surgery. However, among orthopedic surgeons, there remains a lack of consensus regarding the appropriate agent and time course for prophylactic anticoagulation after TJA. In this study, we review the evidence-supported patient-specific factors that confer an increased risk of VTE in the TJA postoperative period. Furthermore, we describe the VTE prophylaxis regimen used at our home institution after TJA for low- and high-risk patients as well as a recommendation for cessation or continuation of anticoagulation regimens that patients were on preoperatively for comorbid conditions.

A Novel Patient Selection Tool Is Highly Efficacious at Identifying Candidates for Outpatient Surgery When Applied to a Nonselected Cohort of Patients in a Community Hospital.

BACKGROUND: There is a paucity of validated selection tools to assess which patients can safely and predictably undergo same-day or 23-hour discharge in a community hospital. The purpose of this study was to assess the ability of our patient selection too to identify patients who are candidates for outpatient total joint arthroplasty (TJA) in a community hospital. METHODS: A retrospective review of 223 consecutive (unselected) primary TJAs was performed. The patient selection tool was retrospectively applied to this cohort to determine eligibility for outpatient arthroplasty. Utilizing length of stay and discharge disposition, we identified the proportion of patients discharged home within 23 hours. RESULTS: We found that 179 (80.1%) patients met eligibility criteria for short-stay TJA. Of the 223 patients in this study, 215 (96.4%) patients were discharged home; 17 (7.9%) were on the day of surgery, and 190 (88.3%) within 23 hours. Of the 179 eligible patients for short-stay discharge, 155 (86.6%) patients were discharged home within 23 hours. Overall, the sensitivity of the patient selection tool was 79%, the specificity was 92%, the positive predictive value was 87% and the negative predictive value was 96%. CONCLUSION: In this study, we found that more than 80% of patients undergoing TJA in a community hospital are eligible for short-stay arthroplasty with this selection tool. We found that this selection tool is safe and effective at predicting short-stay discharge. Further studies are needed to better ascertain the direct effects of these specific demographic traits on their effects on short-stay protocols.

Surgical Technique: Robotic-Assisted 1.5-Stage Exchange Total Knee Arthroplasty for Periprosthetic Joint Infection.

A 1.5-stage exchange total knee arthroplasty for periprosthetic joint infection has been described; however, achieving a balanced and well-aligned construct can sometimes be difficult given the bony defects often encountered in these cases. The use of robotic navigation technologies allows for accurate and precise implant placement. This technique report details the utilization of robotic navigation in a 1.5-stage exchange total knee arthroplasty for periprosthetic joint infection and describes the outcome of 6 patients. This technique guide highlights how robotic technology can account for many commonly encountered bone voids, joint line identification, and component orientation, while achieving a balanced and well-aligned knee.

Remote Patient Monitoring Following Total Joint Arthroplasty.

This review article presents the current state of remote patient monitoring (RPM) in total joint arthroplasty. RPM refers to the use of telecommunication with wearable and implantable technology to assess and treat patients. Several forms of RPM are discussed including telemedicine, patient engagement platforms, wearable devices, and implantable devices. The benefits to patients and physicians are discussed in the context of postoperative monitoring. Insurance coverage and reimbursement of these technologies are reviewed.

Understanding Patient Perspectives Regarding Remote Monitoring Devices Following Total Joint Replacement.

Background: Advances in smart technology have expanded into the field of orthopedic surgery to deliver enhanced patient care. Smart technology has also raised important issues regarding protected patient information. The purpose of this study is to determine patient preferences regarding smart technology in their postarthroplasty care. Methods: Patient surveys were administered in the office setting of 2 adult reconstructive orthopedic surgeons during a 4-week period. Surveys queried patient demographics, twelve yes/no questions, five continuous agree/disagree statements, and a single free-text question. Logistic regression and statistical significance testing were performed. Results: Of the study patients, 83.6% were willing to wear a device. Women were more likely to consent to a monitoring device and have activity data collected than men (P < .05). Younger patients were more likely to consent to a device and have data collected than octogenarians. Nearly 90% of respondents indicated peace of mind with data being constantly tracked. However, 64% of respondents had hesitations about a surgically implanted device that was independent of a previous arthroplasty surgery (P < .05). Conclusions: Patients are comfortable with smart technology being involved in their postoperative care, especially younger patients and women. Older individuals, possibly with less experience using smart technology in their lives, were not as willing to wear smart devices or have their data collected. Nearly two-thirds of patients had hesitations about surgically implanted smart devices. Further investigation is needed to understand hesitations concerning smart implants as the orthopedic community enters an era of commercially available smart implants in total joint arthroplasty.

Irrigation Solutions in Total Joint Arthroplasty.

INTRODUCTION: Despite advancements in the field of adult reconstruction, prosthetic joint infection (PJI) remains a common and devastating complication of total joint arthroplasty. Eradication of these infections can often prove difficult, and they remain a source of considerable morbidity and mortality. This clinical review paper will focus on some of the more commonly used irrigation solutions; povidone-iodine (PI), chlorhexidine (CHG), acetic acid (AA), hydrogen peroxide (HP), antibiotic irrigations, taurolidine, and polyhexanide-betaine (PB). SUMMARY OF THE EVIDENCE: Significant research has been performed on the prevention of PJI, including use of intraoperative joint irrigation solutions. Several solutions have been theorized to aid in infection prevention, but no evidence-based practice guidelines in this area of orthopaedics have been established. There is a paucity of prospective randomized control trials to compare the efficacy of these joint irrigation solutions. CONCLUSIONS: The authors present a review regarding seven major categories of commonly used intraoperative joint irrigation solutions. The current literature fails to demonstrate a clear consensus for a preferred solution and concentration for povidone-iodine, chlorhexidine, hydrogen peroxide, acetic acid, antibiotic irrigations, taurolidine, and polyhexanide-betaine. Prospective, randomized control trials directly comparing these different irrigation solutions are needed.

Does Time Spent in the Post-Anesthesia Care Unit Affect Hospital Lengths of Stay following Primary Total Knee Arthroplasty?

Given the current healthcare economic environment, substantial efforts have been made to help streamline the in-hospital care for total knee arthroplasty (TKA) patients. While potential cost-reducing factors have been identified in the literature, analyses specifically considering post-anesthesia care unit (PACU) lengths of stay (LOS) are lacking. Therefore, the purpose of this study was to identify factors associated with (1) longer PACU LOS as well as (2) longer Hospital LOS. Prospectively collected TKA data from seven participating hospitals within a large health system were evaluated for patient demographics, body mass indices, Charlson Comorbidity Indices (CCI), surgeon volumes/training, admission types, anesthesia types, PACU LOS, and overall hospital LOS. Complete data was available for 1,690 patients (1,082 females, mean age: 67 years). Univariate and multivariate analytical models were constructed to identify which factors were predictive of longer PACU and overall hospital LOS. Same-day admissions, higher volume surgeons (≥ 100 cases per year), fellowship-trained arthroplasty surgeons, and longer operative times were associated with longer PACU LOS (p < 0.05). Multivariate analyses found age more than or equal to 65 years (ß= 0.124) and CCI more than or equal to 3 (ß= 0.088) to be associated with longer hospital LOS (p < 0.001). Operative times, PACU LOS, and procedure times (operative time plus PACU LOS) were not associated with longer hospital LOS (p > 0.05). These data identify associative factors for PACU LOS, as well as the influence of time spent in the PACU on overall hospital LOS. Interestingly, this analysis revealed that patients of arthroplasty fellowship-trained and higher-volume surgeons had longer PACU LOS; however, this could be explained by the observation that these particular surgeons tend to perform more complex deformity cases. Also of importance, increased PACU LOS, meaning the patient spent more time in a high-monitored setting immediately after surgery, did not necessarily confer a longer overall hospital LOS. Based on these data, it may be more beneficial to identify alternate sources than time spent in the operating room or PACU to potentially help reduce overall hospital LOS. LEVEL OF EVIDENCE: II, prospective cohort.

Management of Refractory Pain After Total Joint Replacement.

PURPOSE OF REVIEW: Chronic pain after total joint replacement (TJA), specifically total knee replacement (TKA), is becoming more of a burden on patients, physicians, and the healthcare system as the number of joint replacements performed increases year after year. The management of this type of pain is critical, and therefore, understanding the various modalities physicians can use to help patients with refractory pain after TJA is essential. RECENT FINDINGS: The modalities by which chronic pain can be successfully managed include genicular nerve radioablation therapy (GN-RFA), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), and peripheral subcutaneous field stimulation (PSFS). Meta-analyses and case reports have demonstrated the effectiveness of these treatment options in improving pain and functional outcomes in patients with chronic pain after TKA. The purpose of this paper is to review and synthesize the current literature investigating the different ways that refractory pain is managed after TJA, with the goal being to provide treatment recommendations for providers treating these patients.

Annual Nationwide Infection Trends for Revision Total Knee Arthroplasty.

Several recent intraoperative and wound management techniques have been developed and implemented in the United States over the past decade; however, it is unclear what the effects of these newer modalities have on reducing surgical site infection (SSI) rates. Therefore, the purpose of this study was to track the annual rate and trends of (1) overall, (2) deep, and (3) superficial SSIs following revision total knee arthroplasty (TKA). The National Surgical Quality Improvement Program database was queried for all revision TKA cases performed between 2011 and 2016, which yielded 9,887 cases. Cases with superficial and/or deep SSIs were analyzed separately and then combined to evaluate overall SSI rates. After an overall 6-year correlation and trends analysis, univariate analysis was performed to compare the most recent year, 2016, with the preceding 5 years. Correlation coefficients and chi-square tests were used to determine correlation and statistical significance. No significant correlations between combined, deep, and/or superficial SSI rates and year were noted (p > 0.05). The lowest overall SSI incidence was in 2012 (1.16%), while the greatest incidence was in 2014 (1.76%). The deep SSI incidence over the 6 years was 0.67% (66 out of 9,887 cases). Deep SSI rate decreased by 10% in 2016 compared with 2011 (0.50 vs. 0.56%, p > 0.05). In this 6-year period, 94 cases out of 9,887 were complicated by a superficial SSI, an incidence of 0.95%. The lowest superficial SSI incidence occurred in 2015 (n = 17, 0.77%). Overall, the incidence of SSIs in revision TKA has remained fairly low with some annual variance, indicating room for improvement. These variations likely as revision surgeries can be more complex and have several associated confounding factors influencing outcomes, when compared with primary cases. Further research is needed to identify revision-specific strategies to reduce the risk of surgical site infections.

Arthroplasty during the COVID-19 Pandemic.

This article aims to give a brief outline of the pathogenesis and transmission of SARS-CoV-2 and how to safely navigate an arthroplasty practice during and after the pandemic.

Educating Surgeons to Educate Patients About the COVID-19 Pandemic.

The spring of 2020 has been a trying time for the global medical community as it has faced the latest pandemic, COVID-19. This contagious and lethal virus has impacted patients and health care workers alike. Elective surgeries have been suspended, and the very core of our health care system is being strained. The following brief communication reviews pertinent details about the virus, delaying elective surgeries, and what patients can do during this time. The goal is to disseminate factual data that surgeons can then use to educate their patients.

The Effect of Bladder Catheterization on Ambulation and Venous Thromboembolism Following Total Knee Arthroplasty: An Institutional Analysis.

BACKGROUND: Although intermittent catheters are immediately removed, indwelling catheterization may lead to decreased ambulation and participation in physical therapy, critical components to post-total knee arthroplasty (TKA) management. Therefore, this study aimed to compare the effect of catheterization treatments on (1) postoperative ambulation distances, (2) deep vein thromboses (DVTs), and (3) pulmonary emboli (PEs) following TKA. METHODS: A total of 9123 prospectively collected primary TKA patients were assessed based on postoperative catheter status. Patient demographics, Charlson Comorbidity Indices, body mass indices, DVT prophylaxes, first ambulation distances, DVTs, and PEs were collected at approximately mean 12 months of follow-up. Univariate and multivariate analyses were performed with independent t-tests and multiple linear regression models in order to compare catheterization techniques. RESULTS: There were 1193 patients who had urinary retention and treated with either indwelling only (62%, n = 734), both indwelling and intermittent catheterizations (13%, n = 160), or intermittent only (25%, n = 299). Multivariate analyses found that indwelling catheter-only use had an 11% decrease in ambulation distance (P < .001). Additionally, the indwelling catheterization-only group was found to be at increased risk of DVTs (odds ratio 2.605, P < .001), even after controlling for DVT prophylaxes (odds ratio 2.807, P < .001). CONCLUSION: This study showed that the use of an indwelling catheter for treatment of urinary retention significantly decreased TKA patient ambulation distance and subsequently increased the risk for DVTs. This information is important as we would recommend the treatment with intermittent catheterization rather than indwelling catheters to decrease the risk of immobilization and postoperative DVTs.

Does Intermittent Catheterization Compared to Indwelling Catheterization Decrease the Risk of Periprosthetic Joint Infection Following Total Knee Arthroplasty?

BACKGROUND: Catheterization for the prophylaxis against or treatment for urinary retention commonly occurs after total knee arthroplasty (TKA). Recent studies have questioned the use of the indwelling catheterization, especially in its potential role as a nidus for infection. We are still unsure of its downstream effects on periprosthetic joint infections (PJIs). Therefore, this study aimed to compare the risks of postoperative PJI following intermittent vs indwelling catheterization after TKA. METHODS: Between 2017 and 2019, 15 hospitals in a large health system collected data on patients undergoing TKA. Patient treatments with indwelling catheter only, intermittent straight catheter only, and both indwelling and intermittent straight catheterizations were recorded. Patient demographics, comorbidities, body mass indices, and PJIs were collected from time of surgery to time of data collection at mean 14 months of follow-up. Univariate and multivariate analyses were performed with independent t-tests and multiple linear regression models to compare catheterization treatment types. RESULTS: A total of 9123 TKAs were performed, with patients receiving indwelling catheter only (62%, n = 734), intermittent straight catheter only (25%, n = 299), or both indwelling and intermittent catheterizations (13%, n = 160). Univariate analyses showed that PJIs occurred in 1.1% of no-catheter patients and 2.3% of patients treated with bladder catheterization (P = .002). Using multivariate analyses, indwelling catheter use (odds ratio [OR] 2.647, P < .001), diabetes (OR 1.837, P = .005), and peripheral vascular disease (OR 2.372, P = .046) were found to have a statistically significant increased risk for PJIs. The use of intermittent straight catheterization (OR 1.249, P = .668) or both indwelling and intermittent (OR 1.171, P = .828) did not increase the risk for PJIs. CONCLUSION: Urinary bladder catheterization is commonly required for prophylaxis against or treatment for urinary retention following TKA. The use of a urinary catheter can provide a potential nidus for infection in these patients. This study found that indwelling catheterization, but not intermittent catheterization, was associated with an increased risk for PJI. Surgeons should therefore limit the duration of catheterization in an effort to decrease the risk for PJI.

The Cumulative Effect of Substance Abuse Disorders and Depression on Postoperative Complications After Primary Total Knee Arthroplasty.

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 = .022), and aseptic loosening (P = .007). AUD was associated with PJI (P < .001) and deep vein thromboses (P = .003). Multivariate analyses found that AUD (OR: 19.419, P < .001) and SUD (OR:3.693, P = .010) were independent risk factors for PJI. Compared with SUD alone, patients with depression plus SUD were found to have a 4-fold (OR: 13.639, P < .001) and 2-fold (OR:4.401, P = .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.

The Effect of Bladder Catheterization Technique on Postoperative Urinary Tract Infections After Primary Total Hip Arthroplasty.

BACKGROUND: Urinary bladder catheters are potential sources of infection after total hip arthroplasty (THA). Therefore, the goal of this study was to determine if intermittent catheterization provides a decreased risk of postoperative urinary tract infections (UTIs) compared with indwelling catheterization in THA patients. METHODS: Patients undergoing THA at 15 hospitals within a large health system were prospectively collected between 2017 and 2019 and then stratified based on catheterization technique: no-catheter; indwelling catheter-only; intermittent catheter-only; and both intermittent and indwelling catheter. Patient demographics, medical comorbidities, anesthesia types, and postoperative UTIs were assessed. Independent Student t-tests were used to perform univariate analyses for the catheterization groups. Multiple linear regression models were used to compare the different groups while controlling for confounding variables. RESULTS: There were a total of 7306 THA patients recorded with 5513 (75%) no-catheter, 1181 (16%) indwelling catheter-only, 285 (3.9%) intermittent catheter-only, and 327 (4.5%) indwelling and intermittent catheterization patients. A total of 580 patients experienced postoperative UTI. Urinary bladder catheterization increased the risk of postoperative UTIs (P < .001) in univariate analyses. Multiple linear regression models showed that indwelling catheter-only (OR: 2.178, P < .001), intermittent catheterization (OR: 1.975, P = .003), and both indwelling and intermittent (OR: 2.372, P = .002) were more likely to experience UTIs compared with no catheters. CONCLUSION: This study found that patients treated with indwelling catheterization, with or without preceding intermittent catheterization, were significantly more likely to experience UTIs. Therefore, in an effort to decrease the risk of UTIs, THA patients experiencing postoperative urinary retention should be treated with intermittent catheterization.

A Step in the Right Direction: Body Location Determines Activity Tracking Device Accuracy in Total Knee and Hip Arthroplasty Patients.

INTRODUCTION: Step counts measured by activity monitoring devices (AMDs) and smartphones (SPs) can objectively measure a patient's activity levels after total hip and knee arthroplasty (total joint arthroplasty [TJA]). This study investigated the use and optimal body location of AMDs and SPs to measure step counts in the postoperative period. METHODS: This was a two-armed, prospective, observational study of TJA inpatients (n = 24) and 2-week status after TJA (n = 25) completing a 100-ft walk. Observer-counted steps were compared with those measured by AMDs (wrist and ankle) and SPs (hip and neck). Acceptable error was defined as <30%. Error rates were treated as both dichotomous and continuous variables. RESULTS: AMD and SP step counts had overall unacceptable error in TJA inpatients. AMDs on the contralateral ankle and SPs on the contralateral hip had error rates less than 30% at 2 weeks postoperatively. Two-week postoperative patients required lower levels of assist (11/25 walker; 4/25 no assist), and significant improvements in stride length (total hip arthroplasty 1.27 versus 1.83 ft/step; total knee arthroplasty 1.42 versus 1.83 ft/step) and cadence (total hip arthroplasty 74.6 versus 166.0 steps/min; total knee arthroplasty 73.5 versus 144.4 steps/min) were seen between inpatient and postoperative patients. Regression analysis found that increases in postoperative day and cadence led to a decrease in device error. CONCLUSION: In inpatients with TJA, AMDs and SPs have unacceptable variability and limited utility for step counting when using a walker. As gait normalizes and the level of ambulatory assist decreases, AMDs on the contralateral ankle and SPs on the contralateral hip demonstrated low error rates. These devices offer a novel method for measurement of objective outcomes and potential for remote monitoring of patient progress after TJA. LEVEL OF EVIDENCE: Level II, prospective, three-armed study, prognostic study.

The effect of operative time on in-hospital length of stay in revision total knee arthroplasty.

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 (ß=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.