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Stiffness after total knee arthroplasty (TKA) can lead to decreased function and patient dissatisfaction. Manipulation under anesthesia (MUA) is often performed to improve range of motion (ROM); however, there is no consensus on indications or timing. The purpose of this study was to compare clinical results and patient-reported outcome measures (PROMs) between patients who underwent MUA versus those with an uncomplicated postoperative course following primary TKA. This was an institutional review board-approved retrospective review of 116 consecutive patients who underwent MUA from 2013 to 2019 following primary TKA due to stiffness. Indication for MUA was failure to achieve 105 degrees of knee flexion at 6 weeks following surgery. Five patients underwent revision surgery and 15 patients from the MUA group were excluded: 12 lost to follow-up and 3 deaths. The remaining 96 MUA patients were matched to 288 TKAs who did not require MUA or revision, all with a minimum 2-year follow-up. Patients who underwent MUA were younger (60.7 vs. 66.3 years, p  < 0.001) and had less preoperative knee flexion (105.4 vs. 110.7 degrees, p  < 0.001). There were five (4.9%) revisions in the MUA group: two instability, two chronic pain, and one arthrofibrosis. There were no differences between the groups with respect to postoperative Knee Society Knee Score, Western Ontario and McMaster Universities Osteoarthritis, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Forgotten Joint Score-12, satisfaction, or complications. Satisfaction rates were 88.5% among MUA patients and 89.6% among non-MUA patients ( p  = 1.0). Patients undergoing MUA following TKA, using the criteria of failure to achieve 105 degrees of flexion by 6 weeks postoperatively, were able to achieve similar PROMs and satisfaction compared with a control group with a low incidence of revision due to persistent arthrofibrosis., Competing Interests: A.L.M. declares the following conflicts of interest: Stryker: IP royalties; Paid consultant; Paid presenter or speaker; Research support; Parvizi Surgical Innovation: Stock or stock Options., (Thieme. All rights reserved.)

A critical and difficult aspect of total knee arthroplasty (TKA) is ligamentous balancing for which cadavers and models have played a large role in the education and training of new arthroplasty surgeons, although they both have several shortcomings including cost, scarcity, and dissimilarity to in vivo ligament properties. An advanced knee simulator (AKS) model based on computed tomography (CT) scans was developed in the setting of these challenges with cadavers and previous models. In this study, we compared the ligament balancing between AKS and human cadaveric knees to assess the validity of using the AKS for ligament balancing training during TKA. A CT scan of a TKA patient with varus deformity was used to design the AKS model with modular components, using three-dimensional printing. Three fellowship-trained arthroplasty surgeons used technology-assisted TKA procedure to plan and balance three cadaver knees and the AKS model. Medial and lateral laxity data were captured using manual varus and valgus stress assessments for cadavers and the model in an extension pose (10 degrees of flexion from terminal extension) and between 90 and 95 degrees for flexion. After preresection assessments, surgeons planned a balanced cruciate-retaining TKA. Following bony cuts and trialing, extension and flexion ligament laxity values were recorded in a similar manner. Descriptive statistics and Student's t- tests were performed to compare the cadavers and model with a p -value set at 0.05. Preresection medial/lateral laxity data for both extension and flexion were plotted and showed that the highest standard deviation (SD) for the cadavers was 0.67 mm, whereas the highest SD for the AKS was 1.25 mm. A similar plot for trialing demonstrated that the highest SD for the cadavers was 0.6 mm, whereas the highest SD for the AKS was 0.61 mm. The AKS trialing data were highly reproducible when compared with cadaveric data, demonstrating the value of the AKS model as a tool to teach ligament balancing for TKA and for future research endeavors., Competing Interests: None declared., (Thieme. All rights reserved.)

Cementless implant use continues to increase primarily due to increased numbers of younger and obese patients opting for primary total knee arthroplasty (TKA). Given the increased use of cementless implants, the purpose of this study was to evaluate the midterm clinical performance of cementless TKA using a highly porous tibial baseplate compared with its cemented counterpart of the same system. We conducted a retrospective case-control study of 400 patients undergoing primary TKA that included 200 patients with cementless components matched for age and body mass index (BMI) to 200 patients with cemented implants of the same implant design with a 5-year follow-up. We evaluated clinical results, complications, revisions, and overall survivorship between the cohorts. Statistical analysis was performed using student t -test and chi-square analysis. There was no statistical difference in age (64.3 vs. 64.3 p  = 0.81), BMI (34 vs. 33.1 p  = 0.19), preoperative Knee Society Score (KSS) function (41 vs. 32.3 p  = 0.22), and preoperative KSS knee score (39.2 vs. 38.3 p  = 0.54) between the cementless and cemented cohorts, respectively. The cementless group had seven revisions, while the cemented group had nine revisions ( p  = 0.609). The cementless group had one revision due to aseptic loosening versus five in the cemented group ( p  = 0.09). Postoperative 5-year KSS knee scores were 92.84 versus 91.75 ( p  = 0.386) and function scores were 81.81 versus 69.65 ( p  = 0.00004) in the cementless and cemented groups, respectively. The cementless group had survivorship of 96.5% for all-cause revision compared with 95.5% in the cemented group at 5-year follow-up ( p  = 0.60). Cementless TKA using a highly porous tibial baseplate showed excellent midterm results with one case of aseptic loosening at 5-year follow-up and with similar Knee Society outcome scores and survivorship compared with the cemented group. Cementless TKA demonstrated noninferiority to cemented TKA and could be used as an alternative mode of fixation in patients opting for primary TKA. Additional long-term follow-up is needed to determine if cementless TKA can demonstrate improved survivorship over cemented TKA., Competing Interests: A.L.M. reports the following declarations: 1) Stryker: IP royalties, Paid consultant, Paid presenter or speaker, Research support; 2) Parvizi Surgical Innovations: Stock or stock options. All other authors have no declarations., (Thieme. All rights reserved.)

Initial design cementless metal-backed patellar implants failed due to multiple reasons including implant design, use of first-generation polyethylene, and surgical technique. This study evaluates clinical outcomes and survivorship of total knee arthroplasty (TKA) using a current generation highly porous metal-backed patellar component. One-hundred twenty-five consecutive primary cementless TKAs with a compression molded highly porous metal-backed patella were reviewed. One-hundred three TKAs (82.4%) with 5-year clinical and radiographic follow-up were available for review. These were matched with 103 consecutive TKAs using a cemented patella of the same implant design. The cementless cohort had a mean age of 65.5 years, body mass index (BMI) of 33.0, and follow-up of 64.4 months. Indications for cementless TKA were based on multiple factors including age, BMI, and bone quality. There were no revisions for loosening or mechanical failure of the cementless patella compared with two cemented patellae revised for aseptic loosening. Eight patients required revisions in the cementless cohort: three for prosthetic joint infection (PJI), two for instability, one periprosthetic femur fracture, one for patella instability, and one for extensor mechanism rupture. Five patients required revisions in the cemented cohort: two for aseptic patellar loosening, one for aseptic femoral loosening, one for PJI, and one for instability. All-cause survivorship at 5 years was 92.2 and 95.1% for the cementless metal-backed implant and cemented implant cohorts, respectively. Use of a compression molded highly porous metal-backed patella component demonstrated excellent clinical and radiographic results at 5-year follow-up. Longer follow-up is required to evaluate the ability of highly porous cementless patella implants to provide durable long-term fixation., Competing Interests: None declared., (Thieme. All rights reserved.)

Chronic opioid use prior to total knee arthroplasty (TKA) has been implicated in adverse outcomes. The purpose of this study was to evaluate clinical outcome measures and patient satisfaction in patients with a history of preoperative chronic opioid use undergoing primary TKA. A retrospective cohort study was performed on 296 consecutive patients undergoing primary TKA. Seventy-four (25%) patients were identified with chronic preoperative opioid use (study group; 22 males, 52 females). A 3:1 matched cohort ratio of control versus study group was utilized resulting in a control group consisting of 222 patients (97 males, 125 females) without chronic opioid use prior to surgery. There was no statistically significant difference in age, BMI, or follow-up. Average follow-up was 23.4 months in the control group and 23.6 months in the study group ( p  = 0.87). Clinical data including patient satisfaction (Likert score), Knee Society (KS) Knee scores, KS Function scores, Forgotten Joint Score (FJS), length of stay (LOS), and complications were evaluated. Patient satisfaction at the most recent visit was 92.8% in the control group versus 83.8% in the chronic opioid group ( p  = 0.0016). Differences in patient-reported outcomes measures comparing the control and study cohorts included KS Function Score of 83.23 versus 75.31 ( p  = 0.0034). The FJS of 63.7 versus 58 ( p  = 0.1883) and the KS Knee Score of 89.5 versus 88.1 ( p  = 0.4075) were not significant. Postoperative opioid usage for the control versus the study group was 62/222 (27.9%) versus 56/74 (75.7%) at 4 to 8 weeks ( p <0.0001), and 4/222 (1.80%) versus 27/74 (36.5%) at 12 months ( p <0.0001). Overall complication occurrence was 18.9% in the study group versus 11.3% in the control group ( p  = 0.11). Patients with history of chronic preoperative opioid use had significantly lower patient satisfaction and KS Function scores and increased postoperative opioid usage at 12 months compared with patients without a history of opioid use prior to TKA., Competing Interests: None declared., (Thieme. All rights reserved.)

Morbidly obese patients undergoing cemented primary total knee arthroplasty (TKA) can pose a challenging problem with implant survivorship due to greater stress at the cement-bone interface. With the advent of additive manufacturing (three-dimensional printing), highly porous implants are now readily available. The purpose of this study was to review the results of primary TKA in the morbidly obese (body mass index [BMI] ≥ 40) patient using a highly porous cementless tibial baseplate. This is a retrospective study of 167 TKAs in patients with morbid obesity undergoing primary cementless TKA with a minimum 5-year follow-up. A total of 6 patients died and 14 were lost to follow-up, leaving 147 TKAs in 136 patients with a mean follow-up of 66 months (range 60-79 months). The average age was 59 years (range 36-84 years) and average BMI was 45 kg/m 2 (range 39.5-63.9). Clinical results, patient-reported outcome measures, radiographs, and complications were reviewed. There were 9 failures requiring revision, including 3 for aseptic tibial loosening (2.0%), 2 for deep infection (1.4%), 2 for patellar resurfacing (1.4%), 1 for patella instability (0.7%), and 1 for extensor mechanism rupture (0.7%). Knee Society Score (KSS) improved from 48 to 90 at 2- and 5-year follow-up. KSS function score improved from 49 to 68 and 79 at 2- and 5-year follow-up, respectively. Survivorship with aseptic loosening as the endpoint was 98.0% at 5 years. Cementless TKA using a highly porous tibial baseplate in morbidly obese patients demonstrated excellent clinical results with 98% survivorship at 5 years and appears to offer durable long-term biologic fixation as an alternative to mechanical cement fixation in this challenging group of patients., Competing Interests: A.M. declares the following conflicts of interest: Journal of Arthroplasty: Editorial or governing board; Stryker: IP royalties; paid consultant; paid presenter or speaker; research support S.H. declares the following conflicts of interest: Orthopedics: Editorial or governing board SLACK Incorporated: Editorial or governing board; Stryker: IP royalties; Paid consultant; Paid presenter or speaker; Stock or stock Options; Thieme, Inc., Journal of Hip Surgery, Journal of Knee Surgery: Editorial or governing board; Thieme, Inc., Journal of Knee Surgery, Journal of Hip Surgery: Publishing royalties, financial or material support. The rest authors declare no conflict of interest., (Thieme. All rights reserved.)

Peripheral nerve blocks such as a femoral + sciatic block have demonstrated significant pain relief following TKA. However, these nerve blocks have residual motor deficits which prevent immediate postoperative ambulation. The purpose of this study was to compare outcomes in patients undergoing primary TKA with femoral and sciatic (Fem + Sci) motor nerve blocks versus an adductor canal and the interspace between the popliteal artery and the capsule of the posterior knee and adductor canal block (IPACK + ACB) sensory nerve blocks. A total of 100 consecutive patients were reviewed, 50 received Fem + Sci nerve blocks and 50 received IPACK + ACB blocks preoperatively. There were no differences in the two groups with respect to surgical technique, implant type, postoperative pain, and physical therapy protocols. Differences in opioid requirements, length of stay (LOS), distance walked, and common knee scoring systems were analyzed. Among them, 62% IPACK + ACB patients were discharged on postoperative day 1 compared with 14% in the Fem + Sci group ( p  < 0.0001). The IPACK + ACB patients had a shorter LOS (mean 1.48 days vs. 2.02 days, p  < 0.001), ambulated further on postoperative day 0 (mean 21.4 feet vs. 5.3 feet, p  < 0.001), and required less narcotics the day after surgery (mean, 15.7 vs. 24.0 morphine equivalents p  < 0.0001) and at 2 weeks (mean, 6.2 vs. 9.3 morphine equivalents, p  = 0.025). The use of this combination IPACK and ACB demonstrated improved early ambulation with a decrease in opioid use and length of stay compared with a femoral and sciatic motor nerve block in patients undergoing primary TKA., Competing Interests: A.M. reports personal fees and nonfinancial support from Stryker, outside the submitted work., (Thieme. All rights reserved.)

Approximately 20% of the patients are dissatisfied with their total knee arthroplasty (TKA). Computer technology has been introduced for TKA to provide real time intraoperative information on limb alignment and exact flexion/extension gap measurements. The purpose of this study was to determine if patient satisfaction could be improved with the use of robotic-assisted (RA) technology following primary TKA. A total of 120 consecutive patients undergoing RA-TKA with real time intraoperative alignment and gap balancing information were compared with a prospective cohort of 103 consecutive patients undergoing TKA with manual jig-based instruments during the same time period. There were no differences between groups with age, gender, baseline Knee Society Score (KSS) knee and function scores, follow-up, and ASA scores. TKAs were performed using same technique, implant design, anesthesia, and postoperative treatment protocols. Patient satisfaction survey using KSS and Likert scoring system were obtained at 1-year follow-up. Likert scoring system demonstrated 94% of the patients in the RA group were either very satisfied or satisfied versus 82% in the manual instruments TKA group ( p  = 0.005). RA-TKA group had better average scores of all five satisfaction questions although not significant. RA-TKA group had a better average overall satisfaction score of 7.1 versus 6.6 in the manual instrument group, p  = 0.03. KSS function scores were significantly better at 6 weeks and 1 year postoperatively ( p  = 0.02, 0.005), and KSS knee scores were significantly better at 1 year postoperatively ( p  = 0.046). There are multiple reasons for patient dissatisfaction following primary TKA. Using intraoperative computer technology with RA surgery for patients undergoing a primary TKA, a significant improvement in patient satisfaction was demonstrated compared with TKA using conventional manual jig-based instruments. RA surgery provides several advantages in TKA including real time information in millimeters to help obtain balanced gaps, accurate bone cuts, reduced soft tissue injury, and achieve the target alignment which may lead to improved patient satisfaction., Competing Interests: A.M. reports personal fees and nonfinancial support from Stryker, outside the submitted work. All the other authors report no conflict of interest., (Thieme. All rights reserved.)

The effort to reduce overall healthcare costs may affect more complex patients, as their pre- and postoperative care can be substantially involved. Therefore, the purpose of this study was to use a large nationwide insurance database to compare (1) costs, (2) reimbursements, and (3) net losses of 90-day episodes of care (EOC) for total knee arthroplasty (TKA) patients according to Elixhauser's Comorbidity Index (ECI) scores. All TKAs performed between 2005 and 2014 in the Medicare Standard Analytic Files were extracted from the database and stratified based on ECI scores, ranging from 1 to 5. ECI 1 patients served as the control cohort, while ECI 2, 3, 4, and 5 patients were considered study cohorts. Each study cohort and control cohort were matched based on age and sex, resulting in a total of 715,398 patients included for analysis. Total EOC costs, reimbursements, and total net losses (defined as total EOC costs minus total EOC reimbursements) were compared between the cohorts. Overall, total EOC costs increased with ECI. For example, compared with the matched ECI 1 cohorts, the total EOC costs for ECI 5 patients ($56,589.19 vs. $51,747.54) were significantly greater ( p  < 0.01). Although reimbursements increased with increasing ECI, so did net losses. The net losses for ECI 5 patients were greater than that for ECI 1 patients ($42,309.39 vs. $40,007.82). The bundled payments for care improvement (BPCI) and comprehensive care for joint replacement (CJR) are alternative payment models that might de-incentivize treatment of more complex patients. Our study found that despite increasing reimbursements, overall costs, and therefore net losses, were greater for more complex patients with higher ECI scores., Competing Interests: G.S. reports other from Convatec, Acelity, Biomet, Medtronic, Pacira, Zimmer, Force Therapeutics, Springer, Elsevier, Thieme, World Scientific, and Operation Walk USA, outside the submitted work. A.M. reports other from Stryker, Journal of Arthroplasty, and American Academy of Orthopedic Surgeons, outside the submitted work. M.R. reports other from Stryker, Orthosensor, Smith and Nephew, outside the submitted work. M.A.M. reports other from Stryker, Microport, DJ Orthopedics, Johnson and Johnson, Medical Compression Systems, Merz, Orthosensor, Pacira, Sage Products, Tissue Gene, US Medical Innovations, National Institutes of Health (National Institute of Arthritis and Musculoskeletal and Skin Diseases [NIAMS] and National Institute of Child Health and Human Development [NICHD]), Ongoing Care Solutions, American Journal of Orthopedics, Journal of Arthroplasty, Journal of Knee Surgery, Orthopedics, Surgical Technology International, American Academy of Orthopedic Surgeons, outside the submitted work., (Thieme. All rights reserved.)

The etiology of failure following primary total knee arthroplasty (TKA) leading to revision surgery are multifactorial, including infection, instability, loosening, contracture, and wear. Although the majority of patients have successful outcomes following revision TKA, postoperative complications are still increased in these patients when compared to primary patients. For this reason, there has been a continued search to identify options, including prosthesis types, to potentially improve outcomes. Therefore, the purpose of this study was to determine if the clinical results achieved following revision TKA are comparatively similar to primaries using the same implant design. Specifically, we compared (1) Knee Society Functional and Range-of-Motion Knee Scores and (2) component survivorship. This was a retrospective analysis of 100 patients undergoing revision TKA due to an aseptic etiology, who were matched to a cohort of 100 patients who underwent primaries with the same prosthesis. There were no differences in the groups with respect to age at surgery, sex, and body mass index. The mean follow-up was 57 months in the revision group (range 24-105 months) and 67 months in the primary TKA group (range 55-123 months). American Knee Society Scores (KSS) and range of motion measurements recorded preoperatively and at the most recent postoperative visit were compared between both cohorts in order to compare postoperative outcomes. A p value of 0.05 was used for significance. The average improvement between the pre- and postoperative KSS function scores in both groups was similar, with both cohorts demonstrating a 28-point improvement. At 2-year follow-up, all-cause survivorship of the aseptic revision surgeries was 87%. Patients undergoing revision TKA for aseptic loosening can potentially expect similar improvements in clinical function scores and survivorship compared to primary TKA when controlling for implant type., Competing Interests: M. A. M. reports personal fees from Microport, personal fees and other from Stryker, personal fees and other from DJ Orthopaedics, personal fees and other from Johnson and Johnson, personal fees from Medical Compression Systems, personal fees from Merz, personal fees and other from Orthosensor, personal fees from Pacira, personal fees from Sage Products, personal fees and other from TissueGene, personal fees from US Medical Innovations, other from National Institutes of Health, and other from Ongoing Care Solutions, outside the submitted work. A. L. M. reports other from Stryker Orthopedics, during the conduct of the study; personal fees and nonfinancial support from Stryker Orthopedics, outside the submitted work. All other authors declare no conflict of interest., (Thieme. All rights reserved.)

The purpose of this study was to determine the risk factors associated with reinfection in patients treated with irrigation and debridement (I&D) with liner exchange for an acute (less than 3 months) prosthetic joint infection following the index primary total knee arthroplasty (TKA). Medicare claims database was queried to identify patients with periprosthetic joint infection within 3 months of their index TKA who underwent I&D with tibial polyethylene liner exchange. Exclusion criteria included age < 65 years and < 1 year of claims prior to TKA. A total of 341 patients met our criteria and were analyzed by age, sex, diabetes, obesity, Charlson comorbidity score, and time between TKA and I&D with liner exchange. Average time to I&D with liner exchange following primary TKA was 38.5 ± 21.3 days and multivariate analysis showed a significantly higher risk of reinfection within 1 year in patients > 85 years old ( p  < 0.001) and diabetes ( p  < 0.02). The risk of reinfection was lowest for patients treated with I&D with liner exchange within 14 days after TKA ( p  = 0.028). The incidence of reinfection was 223% greater if I&D with liner exchange was performed 2 to 4 weeks after primary TKA ( p  < 0.03), and 277% higher if performed > 6 weeks after index procedure compared with those performed within 2 weeks. Patients older than 85 years, diabetics, or treated with I&D with liner exchange > 14 days following the primary TKA had a significantly higher risk of reinfection within 1 year. Patients should be cautioned on the risk of reinfection prior to proceeding with I&D with liner exchange > 2 weeks following the index procedure., Competing Interests: None declared., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Alignment after total knee arthroplasty (TKA) plays an important role with respect to patient satisfaction and implant survivorship. In patients undergoing ipsilateral TKA with prior total hip arthroplasty (THA), the femoral intramedullary (IM) guide cannot be fully inserted into the femoral canal because of the prior THA. The purpose of this study was to determine the effect of femoral component alignment using a shorter IM guide during TKA in patients with an ipsilateral THA. We identified 42 patients undergoing ipsilateral TKA with the use of a short IM guide in the setting of a prior THA. A matched cohort group was identified from our total joint registry that included 42 patients who underwent primary TKA. The surgical goal was to achieve 5 degrees of valgus on the femoral side and 0 degree on the tibial side with an overall postoperative tibial-femoral angle of 5 degrees of valgus. Patients were evaluated clinically using Knee Society pain scores (KSSs), function scores, and with radiography. Both the tibial-femoral limb alignment and the femoral component alignment were compared using Student's t -test. There were no significant differences between the two groups with respect to sex, age, body mass index (BMI), pre- and postoperative KSSs. There was a statistically significant difference between the two groups with respect to radiographic tibial-femoral limb alignment, 4.33 degrees of valgus in the short stem THA-TKA group versus 5.4 degrees of valgus in the TKA group ( p  < 0.04); however, this difference did not correlate to a difference in postoperative outcomes. An adequate tibial-femoral component alignment was achieved in patients undergoing ipsilateral TKA with prior THA using a shortened IM femoral guide., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Competing Interests: Disclosure The authors report no conflicts of interest in this work.

As with most new surgical technologies, there is an associated learning curve with robotic-assisted total knee arthroplasty (TKA) before surgeons can expect ease of use to be similar to that of manual cases. Therefore, the purpose of this study was to (1) assess robotic-assisted versus manual operative times of two joint reconstructive surgeons separately as well as (2) find an overall learning curve. A total of 240 robotic-assisted TKAs performed by two board-certified surgeons were analyzed. The cases were sequentially grouped into 20 cases and a learning curve was created based on mean operative times. For each surgeon, mean operative times for their first 20 and last 20 robotic-assisted cases were compared with 20 randomly selected manual cases performed by that surgeon as controls prior to the initiation of the robotic-assisted cases. Each of the surgeons first 20 robotic assisted, last 20 robotic assisted, and 20 controls were then combined to create 3 cohorts of 40 cases for analysis. Surgeon 1 : First and last robotic cohort operative times were 81 and 70 minutes ( p  < 0.05). Mean operative times for the first 20 robotic-assisted cases and manual cases were 81 versus 68 minutes ( p  < 0.05). Mean operative times for the last 20 robotic-assisted cases and manual cases were 70 versus 68 minutes ( p  > 0.05). Surgeon 2 : First and last robotic cohort operative times were 117 and 98 minutes ( p  < 0.05). Mean operative times for the first 20 robotic-assisted cases and manual cases were 117 versus 95 ( p  < 0.05). Mean operative times for the last 20 robotic-cohort cases and manual cases were 98 versus 95 ( p  > 0.05). A similar trend occurred when the times of two surgeons were combined. The data from this study effectively create a learning curve for the use of robotic-assisted TKA. As both surgeons completed their total cases numbers within similar time frames, these data imply that within a few months, a board-certified orthopaedic joint arthroplasty surgeon should be able to adequately perform robotic TKA without adding any operative times., Competing Interests: Conflict of Interest: Dr. Mont is a consultant for, or has received institutional or research support from the following companies: Sage Products, TissueGene, OnGoing Care Solutions, DJO Global, Microport, Orthosensor, National Institutes of Health, Stryker, Johnson & Johnson, Pacira Pharmaceuticals, Merz, US Medical Innovations. He is on the editorial/governing board of the American Journal of Orthopedics, Journal of Arthroplasty, Journal of Knee Surgery, and Surgical Technology International. He is board or committee member of AAOS., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Competing Interests: Disclosure The authors report no conflicts of interest in this work.

The purpose of this study was to evaluate the efficacy and safety profiles of topical tranexamic acid (TXA) in patients undergoing elective total knee arthroplasty (TKA) with comorbid conditions precluding them from intravenous (IV) TXA use. A total of 104 patients were divided into two groups: 47 in the normal-risk group and 57 in the high-risk group, with the latter representing those with one or more risk factors for venous thromboembolism (VTE). Demographics were similar between groups, and there were no differences with regard to postoperative changes in hemoglobin (- 3.42 g/dL ± 1.07 and - 3.68 g/dL ± 1.07, p  = 0.214), total drain output (630.2 mL ± 331.6 and 566.9 mL ± 343.9, p  = 0.344), postoperative transfusion rate (2.1 and 3.5%, p  = 0.675), or total number of complications 3 (6.5%) and 5 (8.8%) for the normal- and high-risk groups, respectively ( p  = 0.671). Topical TXA exhibited a similar safety and efficacy profile in reducing postoperative blood loss in a group of patients at increased thromboembolic risk, without a significant increase in complications or thromboembolic events. Topical TXA appears to represent a safe and efficacious alternative to IV TXA in patients at high risk for VTE undergoing TKA., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Magnetic resonance imaging (MRI) or computed tomography-based patient-specific instrumentation (PSI) may allow for reliable alignment and fewer outliers when compared with conventionally instrumented total knee arthroplasty (TKA). However, some authors have suggested that frequent intraoperative surgeon-directed changes may still be required. This study evaluated the accuracy of PSI to predict component sizing and alignment during TKA. A total of 84 patients (89 knees) who underwent a TKA using a PSI system were evaluated. An MRI-based preoperative plan of every knee was provided and approved by the surgeons. This demonstrated the proposed prosthetic component alignment, as well as the femoral, tibial, and bearing insert component size and position. Intraoperative changes to these components were prospectively recorded and compared with the computerized preoperative plan. Major changes were defined as any changes in femoral or tibial resection, size, and position of the components. Minor changes were defined as any change in the size of the polyethylene bearing insert. The preoperative plan was able to correctly predict the size of the implanted tibial and femoral component in 93 and 95.5% of the cases, respectively. Thirteen major intraoperative changes were made. In one knee, the proposed femoral resection was not acceptable (because of the presence of significant amount of osteophytes) and was abandoned in favor of a manual extramedullary guide. In another patient, the proposed femoral and tibial components were upsized. In two other patients, the femoral components were downsized, in four patients, the tibial components were downsized, and in another patient, it was upsized. There were also 16 minor changes, which included 2-mm upsizing of the polyethylene liner in 13 knees and 4-mm upsizing in 3 knees. Surgical experience is necessary to recognize improper component size, incorrect surgical resection, or nonideal alignment when performing TKA using PSI. The authors believe that the design and manufacture of PSI combined with a comprehensive templating resulted in excellent intraoperative concordance of the preoperative plan at the default settings with minimal changes., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)