Planovalgus Foot Deformity in Patients Undergoing Total Hip Arthroplasty Is Associated With Increased Risk of Falls, Implant-Related Complications, and Revisions: A Case-Control Analysis.

BACKGROUND: Pes planus occurs due to the loss of the longitudinal arch of the foot, resulting in altered gait mechanics. This may lead to increased complications following total hip arthroplasty (THA). Thus, the aim of this study was to assess the effects that pes planus has on rates of falls, implant complications, fall-related injuries, and times to revision among THA patients. METHODS: A retrospective review of a private insurance claims database was conducted from 2010 to 2021. Patients who had a diagnosis of congenital or acquired pes planus and cases of THA were identified. Patients undergoing THA with a diagnosis of pes planus were matched to control patients 1:5 based on age, sex, and comorbidity profiles. Logistic regression was utilized to assess for differences in complication rates. RESULTS: A total of 3,622 pes planus patients were matched to 18,094 control patients. The pes planus group had significantly higher rates of falls than the control group (6.93 versus 2.97%, OR [odds ratio]: 2.43; CI [confidence interval]: 2.09 to 2.84; P < .001). Pes planus patients also had significantly greater odds of dislocation (OR: 1.89; CI: 1.58 to 2.27; P < .001), mechanical loosening (OR: 2.43; CI: 2.09 to 2.84; P = .019), and periprosthetic fracture (OR: 2.43; CI: 2.09 to 2.84; P < .001). The pes planus group had significantly greater rates of proximal humerus fractures (P = .008), but no difference was seen in distal radius fractures (P = .102). The time to revision was significantly shorter in the pes planus group (190 versus 554 days, P < .001). CONCLUSIONS: Pes planus in patients undergoing THA is associated with increased risk of complications and faster time to revision. These findings may allow orthopaedic surgeons to identify those patients at risk and allow for more educated patient counseling and operative planning.

Excellent 10-Year survivorship of robotic-arm-assisted unicompartmental knee arthroplasty.

Introduction: Robotic-arm-assisted unicompartmental knee arthroplasty (UKA) is an excellent solution for patients suffering from single-compartment knee arthritis. While outcomes tend to be favorable for UKAs, revision operations, commonly due to component malpositioning and malalignment resulting in accelerated wear, are a major concern. Intraoperative technologies, such as robotic assistance, can help better ensure that implants are positioned based on a patient's specific anatomy and mechanical physiology. However, long-term survivorship and patient-reported satisfaction with robotic-assisted UKAs are limited. Therefore, the purpose of this study was to assess the 10-year outcomes of patients who underwent robotic-arm-assisted unicompartmental knee arthroplasty. Specifically, we evaluated: 1) 10-year survivorships; 2) patient satisfaction scores; and 3) re-operations. Methods: From a single surgeon and single institution, 185 patients who had a mean age of 65 years (range, 39 to 92) and a mean body mass index of 31.6 (range, 22.4 to 39) at a mean of 10 years follow-up were evaluated (range, 9 to 11). For all patients, the same robotic-assistive device was utilized intraoperatively, and all patients underwent standardized physical therapy and received standardized pain control management. Then 10-year survivorships with Kaplan-Meir curves, patient satisfaction evaluations with a 5-point Likert scale, and re-operations were assessed as primary outcomes. Results: Overall implant survivorship was 99%, with only two patients requiring revision surgery. There was one patient who was converted to a total knee arthroplasty, while the other patient underwent polyethylene exchange at 5 weeks for an acute infection with successful implant retention. Overall, 97% of the patients were satisfied with their postoperative outcomes, with 81% of patients reporting being very satisfied. There were two other patients who required arthroscopic intervention: one to remove a cement loose body, the other to remove adhered scar from the fat pad and the anterior cruciate ligament. Conclusion: This study is one of the first to provide longer-term (mean 10-year) survivorship and patient-reported satisfaction outcomes for robotic-assisted UKA patients. These data show strong support for utilizing this surgical technique, as nearly all patients maintained their original prostheses and reported being satisfied after a mean of 10 years. Therefore, based on these results, we recommend the use of robotic assistance when performing UKAs.

Three-dimensional-based native alignment phenotype classification system: Description for use in planning for deformities during total knee arthroplasty.

Introduction: Total knee arthroplasty (TKA) is a complex surgical procedure that traditionally relies on two-dimensional radiographs for pre-operative planning. These radiographs may not capture the intricate details of individual knee anatomy, potentially limiting the precision of surgical interventions. With advancements in imaging technology, there is an opportunity to refine TKA outcomes. This study introduces the Native Alignment Phenotype classification system that is based on pre-operative 3-dimensional computed tomography (CT) scans, aiming to provide a more detailed understanding of knee deformities and their influence on characterizing knee osteoarthritis and planning for TKA procedures. Methods: There were 1406 pre-operative non-weight-bearing CT scans analyzed by a single surgeon experienced with robotically-assisted total knee arthroplasties. These scans were converted into three-dimensional models, focusing on the coronal and sagittal planes. Intraoperatively, the robotic system was used to capture native coronal and sagittal deformities for each patient. These values were captured with the patient's leg held in a non-stress, extension pose. A new classification system, 'The Native Alignment Phenotype', was developed to categorize the specific differences between individual knees. Results: There were four primary knee malalignments identified: varus deformity; valgus deformity; and two deformities in the sagittal plane. These malalignments were further categorized based on the degrees of deviation, creating groups with 5° coronal and sagittal ranges. A total of 77 phenotypic alignment patterns were found based on the analyzed cohort. In the coronal plane, varus HKA deformity between 6 and 10° was the most common, with 36.9% of the cases, followed by varus HKA alignment, which was between 0 and 5°, representing 34.3% of the cases. In the sagittal plane, neutral and flexion contracture deformities between 0 and 5° were the most common, with 32.6% of the cases, followed by a fixed flexion contracture alignment, which was between 6 and 10°, representing 28.7% of the cases. When combining coronal and sagittal planes, the most common alignment was the varus between 0 and 5° with a flexion contracture between 0 and 5° (12.5% of cases), closely followed by the varus between 6 and 10° with a flexion contracture between 6 and 10° (12.4% of cases). Conclusion: The Native Alignment Phenotype classification system offers a nuanced understanding of knee deformities based on three-dimensional (CT scan) assessments, potentially leading to improved surgical outcomes in TKA. By leveraging the detailed data from the CT scans, this system provides a more comprehensive view of the knee's anatomy, emphasizing the importance of individualized, data-driven approaches in knee surgery.

Leg length discrepancy before total knee arthroplasty is associated with increased complications and earlier time to revision.

INTRODUCTION: Leg length discrepancy (LLD) following total knee arthroplasty (TKA) is a common complaint, leading to decreased patient satisfaction. However, the effect of LLD diagnosis prior to TKA on outcomes and complications is not well defined. Thus, this study aimed to assess the effects that LLD has on rates of falls and implant complications, length of stay and readmissions, and implant survivorship following TKA. METHODS: A retrospective review of a private insurance claims database was conducted from 2010 to 2021. All cases of TKA and those with a diagnosis of leg length discrepancy were identified. Patients undergoing TKA with a diagnosis of LLD were matched to control patients 1:5 based on demographic and comorbidity profiles. Two-year fall rates and implant complications, lengths of stay, 90-day readmissions, and time to revision were compared between cohorts. RESULTS: A total of 1,378 LLD patients were matched to 6,889 control patients. The LLD group had significantly higher rates of falls, dislocation, mechanical loosening, periprosthetic fracture, and fibrosis when compared to the control group (all P < 0.01). Additionally, mean length of stay was significantly greater in the LLD group (4.9 days vs. 3.0 days, P < 0.001). There was no significant difference in 90-day readmission rates between groups (P = 0.178). Time to revision was significantly shorter in the LLD group (392 days vs. 928 days, P < 0.001). CONCLUSIONS: Leg length discrepancy in patients undergoing TKA was associated with significantly increased fall risk, rates of implant complications, length of stay, and faster time to revision. The findings of this study may allow orthopedic surgeons to identify those patients at risk and allow for more educated patient counseling and operative planning. LEVEL OF EVIDENCE: III, retrospective case-control study.

Clinical applications of robotic surgery platforms: a comprehensive review.

Robotic surgery has expanded globally across various medical specialties since its inception more than 20 years ago. Accompanying this expansion were significant technological improvements, providing tremendous benefits to patients and allowing the surgeon to perform with more precision and accuracy. This review lists some of the different types of platforms available for use in various clinical applications. We performed a literature review of PubMed and Web of Science databases in May 2023, searching for all available articles describing surgical robotic platforms from January 2000 (the year of the first approved surgical robot, da Vinci® System, by Intuitive Surgical) until May 1st, 2023. All retrieved robotic platforms were then divided according to their clinical application into four distinct groups: soft tissue robotic platforms, orthopedic robotic platforms, neurosurgery and spine platforms, and endoluminal robotic platforms. Robotic surgical technology has undergone a rapid expansion over the last few years. Currently, multiple robotic platforms with specialty-specific applications are entering the market. Many of the fields of surgery are now embracing robotic surgical technology. We review some of the most important systems in clinical practice at this time.

Correction of Coronal Deformity and Intercompartmental Imbalance through Bone Resection.

This review discusses the correction of coronal deformity and intercompartmental imbalance through bone resection in total knee arthroplasty (TKA). To achieve functional knee balance, coronal, rotational, and sagittal alignment are critical to successful patient outcomes. Though variations in coronal alignment are debated as a correlate to positive results, advancements in utilizing implant position, alignment, and soft tissue balance to improve patient outcomes and function are an evolving discussion. This study draws upon existing literature, clinical studies, and surgical techniques related to TKA, including advancements in navigation and robotics. The study highlights the importance of individualized alignment strategies for varus and valgus knees. While mechanical neutral alignment has shown excellent long-term data, reevaluating the anatomic recreation of the patient's joint line obliquity is now being studied extensively. Sensor data and navigation systems contribute to improved outcomes and patient satisfaction. The evolution of navigation and robotics has led surgeons to achieve their target angles consistently and accurately; now, the discussion is around the most effective alignment targets. The classification of various phenotypes assists in the proposed starting points for implant position, but soft tissue tension is required in the input data to achieve global balance and stable motion. Each approach's advantages and limitations are considered. In conclusion, achieving optimal coronal alignment, joint line obliquity, and soft tissue balance is crucial for successful TKA outcomes. Personalized alignment philosophies, supported by three-dimensional data and sensor technology, are evolving to minimize critical errors and enhance functional results. Robotic assistance and future advancements in artificial intelligence and machine learning hold promise for further improving TKA outcomes in the quest for soft tissue stabilization.

Immediate Postoperative Zolpidem Use Increases Risk of Falls and Implant Complication Rates Following Total Hip Arthroplasty: A Retrospective Case-Control Analysis.

BACKGROUND: Zolpidem is the most widely used hypnotic in the United States and has known side effects. However, the morbidity of zolpidem use following total hip arthroplasty (THA) is not well-defined. Thus, the aim of this study was to assess the effects that zolpidem use has on medical and implant complications, falls, lengths of stay, and medical utilizations following THA. METHODS: A retrospective query of a nationwide insurance claims database was conducted from 2010 to 2020. All cases of THA and hypnotic use were identified using procedural and national drug codes. Patients who were prescribed zolpidem within 90 days of surgery were matched to hypnotic naive patients 1:5 based on demographic and comorbidity profiles. The 90-day medical complications, falls, fragility fractures, costs, and readmission rates, as well as 2-year implant complications were compared between cohorts. A total of 50,328 zolpidem patients were matched to 251,286 hypnotic naive patients. RESULTS: The zolpidem group had significantly higher rates of medical complications, falls, and fragility fractures when compared to the hypnotic-naive group. The zolpidem group had significantly higher rates of dislocation, mechanical loosening, and periprosthetic fracture. Likewise, healthcare utilization was significantly greater in the zolpidem group. CONCLUSION: Zolpidem use following THA is associated with significant risk of medical and implant complications, as well as fall risks, increased costs, lengths of stay, and readmissions. The findings of this study may affect discussions between orthopaedic surgeons and their patients on the benefits of sleep quality in their recovery versus the incurred risks of zolpidem use. LEVEL OF EVIDENCE: III, retrospective case-control study.

Low radiation dose calibration and theoretical model of an optical fiber dosimeter for the International Space Station.

The optical-fiber-based dosimeter of the LUMINA project was deployed in August 2021 in the International Space Station in the framework of the Alpha mission. The sensing elements of the dosimeter are P-doped optical fibers, which were proven to be excellent candidates for dosimetry applications. The twofold objective of this paper is to provide a theoretical model for the radiation response of the dosimeter and to report on the experimental work carried out at CERN for the qualification and calibration of the engineering model of the LUMINA dosimeter. Combining the theoretical response and experimental data, the calibration curve of the flight model is obtained. Finally, this study broadens the investigation of the room temperature radiation response of P-doped optical fibers in a range of dose rates 104 times lower than previously reported, from 21µGy(SiO2)/h to145mGy(SiO2)/h.

Robotic-Arm Assisted Lateral Unicompartmental Knee Arthroplasty: Case Series with Minimum Five-Year Follow-Up.

INTRODUCTION: Lateral unicompartmental knee arthroplasty has been shown to be a successful treatment modality for isolated lateral osteoarthritis (OA) of the knee. The reproduction of proper knee kinematics, limb alignment, as well as proper soft tissue balancing and component positioning have been shown to be of the utmost importance for a successful unicompartmental knee arthroplasty (UKA). Robotic assistance has shown to be a reliable tool in order to replicate these factors, as compared to manual instrumentation alone. Recent studies have shown the potential of robotic-assisted surgery in controlling these surgical factors for medial UKA; however, studies assessing outcomes of robotic-assisted lateral UKA (RAUKA) are lacking. Therefore, a retrospective single-center study was performed to assess outcomes of lateral RAUKA. MATERIALS AND METHODS: Patients who underwent lateral RAUKA from a single surgeon at a central institution between January 2008 and June 2017 were identified. All patients received a lateral UKA with a fixed-bearing metal backed onlay tibial component. Patients over the age of 18, with at least a five-year follow-up and a lateral UKA were contacted by phone and asked a series of questions to determine satisfaction and survivorship. Each patient was asked in a "yes" or "no" manner, if they have had their implant revised or reoperated for any reason, and a 5-point Likert scale was used to assess satisfaction. RESULTS: Data was collected from 50 patients (53 knees). Of the patients that responded: 32 (60%) were right knees; 32 (60%) were female, and average follow-up was 7.6 years (5-14 years). Of the 53 knees, one had a revision (98% survivorship). Excluding the revision, 51 (98%) of the included cases were either "very satisfied" or "satisfied" with their surgery. DISCUSSION/CONCLUSIONS: Robotic-arm assisted lateral UKA was found to have high survivorship and a satisfaction rate in patients that had at least a five-year follow-up. In the future, larger prospective comparison studies with longer follow-ups are necessary to adequately compare survivorship and satisfaction rates of robotic-assisted lateral UKA to conventional UKA.

Morbidly Obese Patients Undergoing Unicompartmental Knee Arthroplasty Compared to Total Knee Arthroplasty: A Retrospective Case-Controlled Analysis.

BACKGROUND: In this study, we assess the effects that morbid obesity (body mass index (BMI) ≥ 40) has on: (1) Ninety-day medical complications and readmission rates; (2) costs of care and lengths of stay (LOS); and (3) 2-year implant complications in patients undergoing unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA). METHODS: A retrospective query of TKA and UKA patients were identified using a national database. Morbidly obese UKA patients were matched 1:5 to morbidly obese TKA patients by demographic and comorbidity profiles. Subgroup analyses were conducted using the same process between morbidly obese UKA patients and BMI <40 TKA patients, as well as to BMI <40 UKA patients. RESULTS: Morbidly obese patients who underwent UKA had significantly fewer medical complications, readmissions, and periprosthetic joint infections than TKA patients; however, UKA patients had greater odds of mechanical loosening (ML). The TKA patients had significantly longer LOS (3.0 versus 2.4 days, P < .001), as well as significantly greater costs of care than UKA patients ($12,869 versus $7,105). Morbidly obese UKA patients had similar rates of medical complications, and significantly lower readmissions, decreased LOS, and decreased costs when compared to TKA patients who had a BMI <40. CONCLUSION: In patients who have morbid obesity, complications were decreased in UKA compared to TKA. Moreover, morbidly obese UKA patients had lower medical utilizations and similar complication rates when compared to TKA patients with the recommended cutoff of BMI <40. However, UKA patients had greater rates of ML than TKA patients. A UKA may be an acceptable treatment option for unicompartmental osteoarthritis in morbidly obese patients.

Medial Varus Proximal Tibial Resection is Superior to Pie-Crusting of the Medial Collateral Ligament During Primary Total Knee Arthroplasty.

BACKGROUND: Medial varus proximal tibial (MPT) resection or soft tissue releases (STRs) of the medial collateral ligament (MCL) in the form of pie-crusting can be performed to achieve a balanced knee in a varus deformity. Studies comparing the 2 modalities have not been addressed within the literature. Therefore, the aims of this study were to assess the following: (1) compartmental changes between the 2 methods and (2) changes in patient-reported outcome measurements. METHODS: Using our institution's total joint arthroplasty registry, patients who underwent primary total knee arthroplasty from January 1, 2017, to December 31, 2019, were identified. The MPT resection and STR patients were 1:1 matched with baseline parameters yielding 196 patients. Outcomes of interest included: changes in compartmental pressures at 10, 45, and 90° degrees and change to the Short-Form 12, Western Ontario and McMaster Universities Osteoarthritis Index, and Forgotten Joint Scores (FJSs) at the 2-year follow-up period. A P value less than .05 was used as our threshold for statistical difference. RESULTS: The MPT resection led to significant reductions in compartmental pressures at 10° [43 versus 19 pounds (lbs.), P < .0001], 45° (43 versus 27 lbs., P < .0001), and 90° degrees (27 versus 16 lbs., P < .0001) compared to STR. MPT resection also had significantly improved Short-Form 12 (47 versus 38, P < .0001), Western Ontario and McMaster Universities Osteoarthritis Index (9 versus 21, P < .0001), and Forgotten Joint Score (79 versus 68, P = .005). CONCLUSION: Bone modification was superior to pie-crusting of the MCL in achieving consistent pressure balancing and improved outcomes. The investigation can guide surgeons on the preferred method to achieve a well-balanced knee.

Mid-Term Survivorship, Radiographic and Functional Outcomes of Robotic-Assisted Unicompartmental Knee Arthroplasty.

INTRODUCTION: The use of robotic-arm assistance for medial unicompartmental knee arthroplasty (RAUKA) has become an area of interest to overcome technical challenges, improve accuracy, and optimize patient outcomes. Due to the rise in osteoarthritis (OA) and robotic assistance, well-powered long-term studies are warranted. The aim of this study was to analyze midterm survivorship, radiographic changes, range of motion (ROM), and patient-reported outcome measurements (PROMs) of RAUKA. MATERIALS AND METHODS: Patients who underwent RAUKA for medial compartmental OA were identified from April 2009 to May 2014. The query yielded 162 knees with a mean follow up of 6.5 years. Primary endpoints were to compare survivorship, final mechanical axis alignment, radiographic changes, mean ROM, and changes to the following PROMs: Knee Society Score (KSS), International Knee Documentation Committee (IKDC), and Oxford Knee Score (OKS). Statistical analyses were primarily descriptive. A p-value less than 0.05 was considered statistically significant. RESULTS: There were no revisions of the primary implant, one case required exchange of polyethylene bearing and debridement for deep infection, and five cases required additional surgical intervention with implant retention. Overall survivorship was 100%. Radiographic assessment demonstrated no mechanical loosening or osteolysis surrounding the implant. Mean ROM was 3 to 121.9º. Patients demonstrated a mean functional KSS of 78.55, IKDC of 78.22, and OKS of 43.94. CONCLUSIONS: The study supports excellent mid-term outcomes in patients undergoing RAUKA for medial compartment OA. Longer term follow-up studies are necessary to determine the efficacy of this technology for patients undergoing RAUKA for medial compartment OA.

Do Patients with Paget's Disease Have Worse Outcomes following Primary Total Knee Arthroplasty?

Well-powered studies evaluating the effects of Paget's disease on patient outcomes following primary total knee arthroplasty (TKA) are limited. The objective of this study was to determine whether Paget's disease patients undergoing primary TKA have higher rates of complications. A query of an administrative database was performed identifying Paget's disease patients undergoing primary TKA as the study cohort. Patients who did not have Paget's disease served as a matching cohort. Study group patients were matched in a 1:5 ratio by age, sex, and comorbidities. The query yielded 34,284 patients in the study (n = 5,714) and matched (n = 28,570) cohorts. Outcomes analyzed included length of stay (LOS), costs of care, 90-day medical and surgical complications, and 2-year implant-related complications. Multivariate logistic regression analyses were used to calculate the odds ratios (ORs) of complications. Paget's disease patients undergoing primary TKA were found to have significantly longer in-hospital LOS (4 vs. 3 days, p < 0.0001). Study group patients incurred significantly higher 90-day episode-of-care costs ($15,124.55 vs. $14,610.01, p < 0.0001). Additionally, Paget's disease patients were found to have higher incidences and odds of medical/surgical (25.93 vs. 13.58%; OR: 1.64, p < 0.0001) and implant-related complications (8.97 vs. 5.02%; OR: 1.71, p < 0.0001). Specifically, Paget's disease patients were more likely to have periprosthetic fractures, mechanical loosening, and revision TKAs (p < 0.0001). This study demonstrated that Paget's disease was associated with longer in-hospital LOS, increased costs, and higher rates of complications. The study can be utilized by physicians to adequately educate patients with Paget's disease concerning potential complications following their primary TKA.

Effects of Venous Insufficiency in Patients Undergoing Primary Total Knee Arthroplasty: An Analysis of 1.2 Million Patients.

Chronic venous insufficiency (CVI) is extraordinarily prevalent in our aging population with over 30 million people in the United States suffering from the disease. There is a paucity of data analyzing the effects of CVI on outcomes following total knee arthroplasty (TKA). The purpose of this study was to utilize a nationwide administrative claims database to determine whether patients with CVI undergoing TKA have higher rates of: (1) in-hospital lengths of stay (LOS); (2) readmission rates; (3) medical complications; (4) implant-related complications; and (5) costs of care compared to controls. Using a nationwide database, we matched patients with CVI undergoing TKA to controls without CVI undergoing TKA in a 1:5 ratio by age, sex, and medical comorbidities associated with CVI. Primary outcomes analyzed within the study included LOS, 90-day readmission rates, 90-day medical complications, 2-year implant-related complications, in addition to 90-day total global episode of care costs. The query yielded 1,265,534 patients with (n = 210,926) and without (n = 1,054,608) CVI undergoing primary TKA. Patients with CVI had significantly longer LOS (4 vs. 3 days, p < 0.0001), higher 90-day readmission rates (20.96 vs. 15.34%; odds ratio [OR]: 1.46, 95% confidence interval [CI]: 1.44-1.48, p < 0.0001), and higher odds of medical complications (2.27 vs. 1.30%; OR: 1.76, 95% CI: 1.70-1.83, p < 0.0001) compared to matched controls. Patients with CVI also had higher odds of periprosthetic joint infections (2.23 vs. 1.03%; OR: 2.18, p < 0.0001) and implant-related complications in general (4.27 vs. 2.17%; OR: 2.01, 95% CI: 1.96-2.06, p < 0.0001). Additionally, patients with CVI had higher total global 90-day episode of care costs ($15,583.07 vs. $14,286.95, p < 0.0001). Patients with CVI undergoing TKA have increased LOS, higher odds of medical and implant complications, and increased costs of care compared to those without CVI. The study can be utilized by orthopaedic surgeons to counsel patients on the potential complications following this procedure. This is a level III, retrospective cohort study.

Accuracy of Intraoperative Mechanical Axis Alignment to Long-Leg Radiographs following Robotic-Arm-Assisted Unicompartmental Knee Arthroplasty.

Improper alignment and implant positioning following unicompartmental knee arthroplasty (UKA) has been shown to lead to postoperative pain and increase the incidence of revision procedures. The use of robotic-arm assistance for UKA (RAUKA) has become an area of interest to help overcome these challenges. The accuracy of intraoperative alignment compared with standing long-leg X-rays postoperatively following medial RAUKA has been in question. Therefore, the purpose of this study was to (1) determine final mean intraoperative coronal alignment in extension utilizing an image based intraoperative navigation system, and (2) compare final intraoperative alignment to 6-week weight-bearing (WB) long-leg X-rays. Patients who underwent RAUKA for medial compartmental osteoarthritis were identified from January 1, 2018, to August 31, 2019, through our institution's joint registry. The query yielded 136 (72 right and 64 left) patients with a mean age of 72.02 years and mean body mass index (BMI) of 28.65 kg/m2 who underwent RAUKA. Final intraoperative alignment was compared with WB long leg X-rays 6 weeks postoperatively by measuring the mechanical alignment. Statistical analysis was primarily descriptive. Pearson's correlation coefficient was used to determine the relationship between intraoperative alignment to 6-week alignment. A p-value of <0.05 was considered statistically significant. Mean intraoperative coronal alignment after resections and trialing was 4.39 varus ± 2.40 degrees for the right knee, and 4.81 varus ± 2.29 degrees for the left knee. WB long-leg X-rays 6 weeks postoperatively demonstrated mechanical axis alignment for the right and left knees to be 3.01 varus ± 2.10 and 3.7 varus ± 2.38 degrees, respectively. This resulted in a change in alignment of 1.36 ± 1.76 and 1.12 ± 1.84 degrees for the right and left knees, respectively (p < 0.05). Pearson's correlation coefficient demonstrated a correlation of 0.69 between intraoperative to long-leg-X-ray alignment. RAUKA demonstrates excellent consistency when comparing postoperative WB long-leg X-rays to final intraoperative image-based non-WB alignment.

What are the Causes, Costs and Risk-Factors for Emergency Department Visits Following Primary Total Hip Arthroplasty? An Analysis of 1,018,772 Patients.

BACKGROUND: Well-powered studies analyzing the relationship and nature of emergency department (ED) visits following primary total hip arthroplasties (THAs) are limited. The aim of this study was to: 1) compare baseline demographics of patients with/without an ED visit; 2) determine leading causes of ED visits; 3) identify patient-related risk factors; and 4) quantify 90-day episode-of-care healthcare costs divided by final diagnosis. METHODS: Patients undergoing primary THA between January 1, 2010 and October 1, 2020 who presented to the ED within 90-days postoperatively were identified using the Mariner dataset of PearlDiver, yielding 1,018,772 patients. This included 3.9% (n = 39,439) patients who did and 96.1% (n = 979,333) who did not have an ED visit. Baseline demographics between the control/study cohorts, ED visit causes, risk-factors, and subsequent costs-of-care were analyzed. Using Bonferroni-correction, a P-value less than 0.002 was considered statistically significant. RESULTS: Patients who presented to the ED post-operatively were most often aged 65-74 years old (41.09%) or female sex (55.60%). Nonmusculoskeletal etiologies comprised 66.8% of all ED visits. Risk factors associated with increased ED visits included alcohol abuse, depressive disorders, congestive heart failure, coagulopathy, and electrolyte/fluid derangements (P < .001 for all). Pulmonary ($28,928.01) and cardiac ($28,574.69) visits attributed to the highest costs of care. CONCLUSION: Nonmusculoskeletal causes constituted the majority of ED visits. The top five risk factors associated with increased odds of ED visits were alcohol abuse, electrolyte/fluid derangements, congestive heart failure, coagulopathy, and depression. This study highlights potential areas of pre-operative medical optimization that may reduce ED visits following primary THA.

Risk of Periprosthetic Joint Infection After Intra-Articular Corticosteroid Injection Following Unicompartmental Knee Arthroplasty.

BACKGROUND: Perioperative intra-articular joint injection is a known risk factor for developing prosthetic joint infection (PJI) in the immediate preoperative and postoperative periods for total knee arthroplasty, but is less defined in unicompartmental knee arthroplasty (UKA). The goal of this study was to elucidate the risk of developing PJI after intra-articular corticosteroid injection (IACI) into a post UKA knee. METHODS: A retrospective review of a nationwide administrative claims database was performed from January 2015 to October 2020. Patients who underwent UKA and had an ipsilateral IACI were identified and matched 2:1 to a control group of primary UKA patients who did not receive IACI. Multivariate logistic analyses were conducted to assess differences in PJI rates at 6 months, 1 year, and 2 years. RESULTS: A total of 47,903 cases were identified, of which 2,656 (5.5%) cases received IACI. The mean time from UKA to IACI was 355 days. The incidence of PJI in the IACI group was 2.7%, compared to 1.3% in the control group. The rate of PJI after IACI was significantly higher than the rate in the control group at 6 months, 1 year, and 2 years (all P < .05). The majority of PJI occurred within the first 6 months following IACI (75%). CONCLUSION: In this study, IACI in a UKA doubled the risk of PJI compared to patients who did not receive an injection. Surgeons should be aware of this increased risk to aid in their decision-making about injecting into a UKA. LEVEL OF EVIDENCE: III, retrospective comparative study.

Patients With Previous COVID-19 Infection Can Safely Undergo Primary Total Joint Arthroplasty.

BACKGROUND: The COVID-19 virus is believed to increase the risk of diffusing intravascular coagulation. Total joint arthroplasty (TJA) is one of the most common elective surgeries and is also associated with a temporarily increased risk of venous thromboembolism (VTE). However, the influence of a history of COVID-19 infection on perioperative outcomes following TJA remains unknown. Therefore, this study sought to determine what effect a history of COVID-19 infection had on outcomes following primary TJA. METHODS: A retrospective case-control study using the national database was performed to identify all patients who had a history of COVID-19 and had undergone TJA, between 2019 and 2020. Patients who had a history of both were 1:1 matched to those who did not have a history of COVID-19, and 90-day outcomes were compared. A total of 661 TKA and 635 THA patients who had a history of COVID-19 were 1:1 matched to controls. There were no differences in demographics and comorbidities between the propensity-matched pairs in both TKAs and THAs studied. Previous COVID-19 diagnosis was noted in 28.3% of patients 5 days within TJA and in 78.6%, 90 days before TJA. RESULTS: Patients who had a previous diagnosis of COVID-19 had a higher risk of pneumonia during the postoperative period for both THA and TKA (6.9% versus 3.5%, P < .001 and 2.27% versus 1.21%, P = .04, respectively). Mean lengths of stay were also greater for those with a previous COVID-19 infection in both cohorts (TKA: 3.12 versus 2.57, P = .027, THA: 4.52 versus 3.62, P < .001). Other postoperative outcomes were similar between the 2 groups. CONCLUSION: COVID-19 infection history does not appear to increase the risk of VTE following primary TJA, but appears to increase the risk of pneumonia in addition to lengths of stay postoperatively. Individual risk factors should be discussed with patients, to set reasonable expectations regarding perioperative outcomes.