Integrating Smartphone Applications and Wearable Devices for Postoperative Rehabilitation in Total Knee Arthroplasty: A Critical Review.

BACKGROUND: Smartphone and wearable technologies offer innovative methods for monitoring postoperative recovery in total knee arthroplasty (TKA) patients. This review assessed the benefits of these technologies in postoperative care, focusing on (1) smartphone applications, (2) wearable devices, and (3) their combination. METHODS: A systematic search identified studies on smartphone applications and wearables for post-TKA monitoring. The review analyzed 2,119 studies, with 58 meeting criteria: 25 on applications, 25 on wearables, and 8 on both. Studies were rated with a methodology index as well as by levels of evidence. They were then analyzed by categorizing them by adherence and patient satisfaction, functional outcomes and pain scores, gait analyses and ranges of motion, and measurement and comparison tools. RESULTS: A review of 24 of 25 publications related to smartphone applications used for postoperative recovery in TKA showed the potential for improved patient's satisfaction, gait recovery, pain medication scheduling guidance with improved pain management, cost savings, and functional outcomes. Wearable technologies used in postoperative recovery demonstrated monitoring accuracy in 25 studies. These devices also showed effectiveness in gait and motion analysis. Other demonstrated benefits of the wearables were improved outcomes, return to function, cost reduction, and again, better management of pain due to patient interaction and guidance. Studies that combined applications and wearables demonstrated the individual findings with the addition of adherence, patient's satisfaction, and overall mobility improvement at 3 months. CONCLUSIONS: Smartphone applications and wearables can enhance postoperative rehabilitation for TKA patients. Smartphone applications and wearables have been shown in randomized trials to be accurate, effective, and useful in the postoperative rehabilitation of TKA patients. A recurring theme in the review was improved adherence to care plans and medication schedules that ultimately result in improved functional outcomes. These technologies and the data that they generate offer direct patient benefits and the potential for future cost savings.

The CCJR® Gerard A. Engh Excellence in Knee Research Award: Remote Monitoring of Sleep Disturbance Following Total Knee Arthroplasty: A Cautionary Note.

BACKGROUND: Sleep disturbances are common after total knee arthroplasty (TKA). Despite the rising popularity of wearables to track sleep, little evidence exists in the arthroplasty literature regarding their efficacy. We aimed to correlate validated wearable sleep metrics with patient-reported sleep quality following TKA. METHODS: Patients undergoing primary TKA were consecutively enrolled. Patients used a wearable device preoperatively and 90 days postoperatively to track five previously-validated measures of sleep. Each month, they rated their sleep quality. Wearable sleep data was correlated with patient-reported sleep quality using a point biserial correlation test. Categorical data were compared using Chi-square tests. A total of 110 patients were included. RESULTS: Preoperatively, 20.8% of patients reported "fairly bad" or "very bad" sleep; this increased to 44.4% 30 days postoperatively, then decreased to 26.5% 60 days postoperatively, and to 20.2% 90 days postoperatively. At 30 days postoperatively, time in bed, time asleep, and minutes of rapid eye movement sleep weakly correlated with patient-reported sleep quality (correlations 0.356, 0.345, and 0.345, respectively; P < .001). Sleep quality did not correlate with any wearable metric collected 60 or 90 days postoperatively. CONCLUSIONS: Patient-reported sleep quality following TKA initially worsened postoperatively, then improved to preoperative levels by 90 days. Time in bed, time asleep, and rapid eye movement sleep minutes only weakly correlated with patient-reported sleep quality at 30 days; no other correlations were detected. Surgeons that utilize remote monitoring following TKA should be aware that surrogate measures generated from these devices may correlate weakly, if at all, with the patient-reported outcome of the parameter being studied.

Hot Topics and Current Controversies in Total Knee Arthroplasty.

Total knee arthroplasty continues to evolve. It is important to review some of the current controversies and hot topics in arthroplasty. Optimal knee alignment strategy is now just a matter of debate. Mechanical, kinematic, and functional alignment and the role of robotics in achieving optimum alignment are important topics, along with fixation and outpatient knee arthroplasty.

Sleep Disturbances Following Total Knee Arthroplasty.

BACKGROUND: Sleep disturbances are common after total knee arthroplasty (TKA), yet literature examining sleep and postoperative pain remains sparse. With the use of wearable devices, convenient objective remote sleep monitoring is now possible. We aimed to measure patient sleep following TKA using validated questionnaires and wearable devices to compare sleep patterns to pain scores 90 days postoperatively. METHODS: Adult patients with body mass index < 45 undergoing unilateral primary TKA were enrolled. Patients wore a monitor, which tracked sleep duration and disturbances (getting up at least once during the night). They completed weekly Pittsburgh Sleep Quality Index (PSQI) questionnaires and visual analog scale (VAS) pain scores. Sleep patterns were compared with pain scores and sleep duration was compared with PSQI responses. RESULTS: There were 110 patients included with 54.5% women; average age was 64 years (range, 43-80). VAS scores decreased postoperatively. PSQI overall sleep scores, sleep quantity, and sleep quality worsened for the first 30 days then improved past baseline levels by 90 days. Recorded sleep duration did not change, and recordings did not correlate at any point with VAS scores. PSQI overall score and sleep quantity did not correlate with VAS. At 30 days postoperatively, patients reporting "very bad" sleep had significantly worse VAS scores than those reporting "bad" sleep. CONCLUSION: Patient-reported sleep quality (very bad sleep) correlated well with VAS pain score at 30 days, while sleep duration (monitored or patient-reported) did not correlate with any clinical measure and does not seem to be a useful metric in assessing TKA outcome.

Mid-Term Performance of the First Mass-Produced Three-Dimensional Printed Cementless Tibia in the United States as Reported in the American Joint Replacement Registry.

BACKGROUND: Cementless tibial components have shown improvements in clinical performance compared to predicate designs, though evidence supporting mid-term performance and fixation is scarce. The purpose of this study is to determine the mid-term survivorships, revision rates, and reasons why 3-dimensional printed cementless tibial baseplates (3DTKAs) failed compared to other cementless as well as cemented tibial baseplates reported from the American Joint Replacement Registry (AJRR) data. METHODS: All primary total knee arthroplasty (TKA) cases performed in patients 65 years of age or older within the AJRR from January 2, 2012 through June 30, 2020 were queried. A total of 28,631 3DTKAs were identified from 428 institutions. These were compared to all other "aggregated cementless tibia" (n = 7,577) and "aggregated cemented tibia" (n = 550,133) cases. Centers for Medicare & Medicaid Services data over the same time period were merged with AJRR data to determine survivorship and patient-timed incident revision rates per 1,000 years. Failure reasons were tracked during this study period. RESULTS: At 60 months, Kaplan-Meier implant survivorship was 98.9% (CI 98.7-99.0), 98.3% (CI 97.9-98.6), and 98.4% (CI 98.4-98.5) in the 3DTKA, aggregate cementless, and cemented knee cohorts, respectively (P < .0001). Patient-timed incident revision rates were 3.11 (CI 2.75-3.53), 3.99 (CI 3.34-4.76), and 3.35 (CI 3.28-3.42) for those cohorts, which corresponds to a revision rate of 0.31%, 0.40%, and 0.34% per year. CONCLUSION: In this analysis, 3DTKA had favorable survivorship and lower revision rates compared to aggregate cementless and cemented TKAs implanted from the same national database during the same time period.

Patients' Perceptions of Remote Monitoring and App-Based Rehabilitation Programs: A Comparison of Total Hip and Knee Arthroplasty.

BACKGROUND: Remote monitoring rehabilitation programs are new technologies growing in popularity for patients undergoing lower extremity total joint arthroplasty. The purpose of this study was to assess the patients' perceptions of these technologies. METHODS: Patients who underwent total hip arthroplasty (THA), total knee arthroplasty arthroplasty (TKA), and unicompartmental knee arthroplasty (UKA) from September 2020 to February 2022, and participated in a clinical study utilizing remote monitoring and an app-based rehabilitation program were given a questionnaire 3 months postoperatively to assess their perceptions of these technologies. There were 166 patients who completed the survey (42 THA; 106 TKA; 18 UKA). RESULTS: There were 92% of patients who found the technology easy to use. A majority of patients felt the technologies motivated them. The TKA/UKA patients felt more strongly that these technologies allowed the surgeon to monitor their recovery closely (81.9% versus 65.9%; P = .009). There were 85% of THA patients and 94.5% of TKA/UKA patients recommended these technologies. The THA patients felt more strongly that digital rehabilitation could completely replace in-person physical therapy compared to TKA/UKA patients (85.4% versus 41.3%; P < .001). A majority (83%) of patients recommended a combination of inpatient and technology-assisted rehabilitation (THA 90.2%; 84.4% TKA/UKA). CONCLUSION: The THA and TKA/UKA patients found remote monitoring rehabilitation easy to use, increased motivation, and recommend it to other patients undergoing lower extremity arthroplasty. They recommend a combination of technology and in-person rehabilitation postoperatively. The THA patients felt these technologies could replace in-person rehabilitation programs. LEVEL OF EVIDENCE: IV.

Chitranjan S. Ranawat Award: Tourniquet Use Does Not Impact Trajectory of Total Knee Arthroplasty Early Recovery: A Prospective, Randomized Controlled Trial.

BACKGROUND: The impact of tourniquet use on recovery after total knee arthroplasty (TKA) remains controversial. The purpose of this prospective, single blinded, randomized controlled trial was to investigate the effect of tourniquet use on early recovery after TKA using a smartphone app-based patient engagement platform (PEP) with a wrist-based activity monitor to obtain more robust data on early recovery. METHODS: There were 107 patients undergoing primary TKA for osteoarthritis who were enrolled (54 tourniquet [TQ+]; 53 no tourniquet [TQ-]). All patients utilized a PEP and wrist-based activity sensor for 2 weeks preoperatively and 90 days postoperatively to collect Visual Analog Scale (VAS) pain scores and opioid consumption, as well as weekly Oxford Knee Score (OKS) and monthly Forgotten Joint Score (FJS). There was no difference in demographics between groups. Formal physical therapy assessments were performed preoperatively and 3 months postoperatively. Independent sample t-tests were used for continuous data and Chi-square and Fisher's exact tests were used for discrete data. RESULTS: Tourniquet use did not have a statistically significant impact on daily VAS pain or opioid consumption during the first 30 days postoperatively (P > .05). Tourniquet use did not have a significant impact on OKS or FJS at 30 or 90 days postoperatively (P > .05), or on performance of formal physical therapy testing at 3 months postoperatively (P > .05). CONCLUSION: Using a digital technology to collect daily patient data, we found that tourniquet use has no clinically significant negative impact on pain and function in the first 90 days after primary TKA.

Use of Remote Physiologic and Therapeutic Monitoring Following Total Knee Arthroplasty.

INTRODUCTION: Remote physiologic monitoring (RPM), or remote therapeutic monitoring (RTM), has grown exponentially for the management of chronic medical diseases in Medicare patients. More recently, the application of this technology has ventured into the orthopaedic arena, and more specifically, for total joint arthroplasty. Platforms to expedite this monitoring can provide continuous biodata feedback on digital biomarkers to patients and surgeons, which can potentially help improve and create novel patient-specific recovery pathways. Furthermore, various devices developed for this monitoring might help obviate the need for frequent emergency room visits, readmissions, and prolonged outpatient physical therapy sessions, as well as reduce complications and increase patient satisfaction scores after total joint arthroplasty surgery. However, while there are a number of potential benefits to technology for this type of care, its application following total knee arthroplasty has not been well-studied. Therefore, after an overview of the usage of RPM and RTM, the purpose of this study was to review the current literature regarding three common remote monitoring technologies: 1) smartphone apps; 2) wearables; and 3) combined smartphone apps and wearables. We also considered the potential financial implications of remote physiologic monitoring. MATERIALS AND METHODS: A comprehensive search of the PubMed, Cochrane Library, MedLine, and Web of Science databases was performed. Three main subgroups of monitoring devices were included for analysis: smartphone apps, wearable devices, and combined wearable plus smartphone app platforms. Searches focused on remote physiologic monitoring, patient-specific advantages, financial advantages, billing and coding options, as well as overall efficacy of platforms. RESULTS: The current review found smartphone apps, wearables, and combined smartphone app and wearable platform technologies to be advantageous in the postoperative period following total knee arthroplasty. The wearable components can provide highly accurate and reproducible data, which the user-friendly smartphone app can relay to the patient so they can easily understand their progress. Additionally, through the apps, patients can directly access their surgical team. By constantly collecting and evaluating range of motion and functional data, the surgical team can identify if the patient is appropriately progressing through treatment or if further intervention is warranted. CONCLUSION: The incorporation of the remote physiologic monitoring devices during the post-total knee arthroplasty period shows strong promise as a progress-tracking modality. Published benefits include reduced physical therapy visits, decreased pain scores and reliance on opioids, increased activity levels as assessed by step counts, increased ability to follow less well-performing patients, reduced readmissions, reduced in-person clinic visits, and decreased postoperative costs.

The Impact of Component Design and Fixation on Stress Shielding After Modern Total Knee Arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) tibial baseplate thickness, metallurgy, and implant fixation with cement may influence stress shielding. The purpose of the present study is to compare bone mineral density of 2 cemented and press-fit TKA designs with differing tibial baseplate thicknesses and metallurgy over a 2-year period to assess for changes in stress shielding. METHODS: One-hundred one TKAs were performed in this Institutional Review Board-approved, prospective study. There were 4 cohorts: DePuy Attune cemented and press-fit, and Stryker Triathlon cemented and press-fit. The Attune tibial baseplate was thicker; both cemented tibial and femoral components were cobalt-chromium. The DePuy Attune press-fit had a cobalt-chromium sintered bead porous coating while the Stryker Triathlon was 3-dimensional printed highly porous titanium alloy. All patients had quantitative dual-energy X-ray absorptiometry scans performed at baseline (4-6 weeks postoperatively) and at 1 and 2 years postoperatively. Stress shielding was evaluated by comparing percent change in bone mineral density in 11 radiographic zones over 2 years. RESULTS: Over a 2-year period, there were no differences in stress shielding on the tibial side in either cemented or press-fit between Stryker Triathlon and DePuy Attune; however, there were differences on the femoral side. The press-fit tibial components of the Stryker Triathlon and DePuy Attune had either similar or less stress shielding over a 2-year period compared to their cemented counterparts. CONCLUSION: This study comparing 2 TKA implants with differing tibial tray thickness did not find significant differences in tibial stress shielding between designs. There was a difference in stress shielding on the femoral side between designs, suggesting that longer term follow-up is warranted.

Implant Malalignment may be a Risk Factor for Poor Patient-Reported Outcomes Measures (PROMs) Following Total Knee Arthroplasty (TKA).

BACKGROUND: Implant malalignment may be a risk factor for poor patient-reported outcomes measures (PROMs) following total knee arthroplasty (TKA). METHODS: Postoperative surveys were administered to assess PROMs regarding satisfaction, pain, and function in 262 patients who underwent surgery at 4 centers in the U.S. and U.K (average age, 67.2) at a mean 5.5 years after primary TKA. Postoperative distal femoral angle (DFA), proximal tibial angle (PTA), and posterior tibial slope angle (PSA) were radiographically measured, and outliers were recorded. PROMs were compared between patients with aligned versus malaligned knees using univariate analysis. RESULTS: Patients with DFA, PTA, and PSA outliers were more likely to experience similar or decreased activity levels postoperatively than patients with no alignment outliers, as were patients with 1 or 2 outliers of any kind (P < .05). Patients with DFA, PTA, and PSA outliers were significantly more likely to be dissatisfied with their ability to perform activities of daily living (ADLs), as were patients with 1 or 2 outliers of any kind (P < .05). Patients with DFA and PSA outliers were more likely to be dissatisfied with their degree of pain relief, as were patients with 2 outliers of any kind (P < .05). Finally, patients with DFA and PSA outliers, as well as those with 1 outlier of any kind, were more likely to be dissatisfied with their overall knee function (P < .05). CONCLUSION: DFA, PTA, and PSA outliers represent a significant risk factor for decreased satisfaction with activities of daily living(ADLs), pain relief, and knee function, as well as decreased activity levels. LEVEL OF EVIDENCE: Level III.

James A. Rand Young Investigator's Award: Questioning the "Nickel Free" Total Knee Arthroplasty.

BACKGROUND: A study was performed to measure metal ions present in the knee joint after performing a total knee arthroplasty (TKA) with standard cobalt chromium (CoCr) components as well as with "nickel-free" oxidized zirconium femoral and titanium tibial (OxZr/Ti) components. METHODS: Knee joint fluid was collected prior to arthrotomy, and on postoperative day one to determine the amount of metal debris generated when performing a TKA with standard instrumentation from consecutive cases with CoCr components (n = 24) and OxZr/Ti components (n = 16). RESULTS: CoCr implant patients had statistically higher levels of nickel (Ni) (29.7%, P = .033), cobalt (Co), (1,100.7%, P < .0001) and chromium (Cr) (118.9%, P < .0001) postoperatively. The cutting blocks and sawblades do not contain Co, which therefore must have come from the components. The metal ions generated from the sawblades and cutting blocks, therefore, could be discerned from the OxZr/Ti whose components don't contain Co, Cr, or Ni. The OxZr patients had significantly higher Cr (9.5×, P < .001) and Ni (5.1×, P < .001) post-TKA vs pre-TKA; Co levels were not significantly different as expected with the absence of Co in the components (P = .60). The Ni levels generated in performing an Oxinium TKA was 3.3 times higher than when performing a CoCr TKA (1.37 vs. 41 ppb, P < .001). CONCLUSIONS: The substantial degree of Ni generation resulting from performing a hypoallergenic "nickel-free" TKA calls into questions the rationale of utilizing more expensive lower Ni components on the basis of known or suspected Ni or Cr allergy.

Is Apixaban Safe and Effective for Venous Thromboembolism Prophylaxis After Primary Total Hip and Total Knee Arthroplasties?

BACKGROUND: Venous thromboembolism (VTE) is a serious complication of total hip arthroplasty (THA) and total knee arthroplasty (TKA). Apixaban is approved for VTE prophylaxis. This study seeks to ascertain the risk of VTE and bleeding complications in patients undergoing primary THA and TKA receiving apixaban for postoperative VTE prophylaxis for one of the following indications: high risk for VTE, previously on apixaban, and contraindication to the use of aspirin. METHODS: This is a retrospective cohort study of patients who underwent primary THA or TKA over a 17-month period and were prescribed apixaban for thromboprophylaxis postoperatively. RESULTS: 230 patients were included in the study, 110 TKA and 120 THA. The primary reasons for high-risk VTE status included personal and family history of VTE, and 13% were taking apixaban preoperatively for atrial fibrillation. 1 patient (0.43%) who underwent TKA had a DVT with PE. 2.6% of patients had wound complications requiring operative treatment, and 0.87% of THA patients underwent revision arthroplasty. CONCLUSION: The use of apixaban for VTE prophylaxis after primary THA and TKA in patients at high risk for VTE, in patients previously on apixaban, and in patients with a contraindication to the use of aspirin is associated with a low risk of VTE and bleeding complications.

Total Hip Arthroplasty in Patients With Osteoarthritis Associated With Legg-Calve-Perthes Disease: Perioperative Complications and Patient-Reported Outcomes.

BACKGROUND: Complications and patient-reported outcomes (PROs) of total hip arthroplasty (THA) in patients with Legg-Calve-Perthes disease (LCPD) have demonstrated variable results. The purpose of this study was to use a validated grading scheme to analyze complications associated with THA in patients with residual LCPD deformities. Second, we report PROs and intermediate-term survivorship in this patient population. METHODS: A retrospective, single-center review was performed on 61 hips in 61 patients who underwent THA for residual Perthes disease. Average patient age was 42 years and 26% of hips had previous surgery. Complications were determined and categorized using a validated grading scheme that included five grades based on the treatment required to manage the complication and on persistent disability. PROs were compared from preoperative to most recent follow-up time points. RESULTS: Major complications (grade III) occurred in three patients (5%) which each required a second surgical intervention. The most common minor grade I or II complications (11.5%) were asymptomatic heterotopic ossification (3.3%). Patients were lengthened on the surgical side an average of 1.4 cm with no nerve palsies. All patient PROs improved from preoperative to postoperative time points with the modified Harris Hip Score improving from 46.9 preoperatively to 85.4 postoperatively (P < .01). Patients free from revision for any reason at final follow-up (5.6 years; range 2-13 years) was 98.4% with one patient needing a revision of their femoral component. CONCLUSIONS: THA for the sequelae of the LCPD has an acceptable complication rate and provides excellent patient reported outcomes at mid-term follow-up.

Is the Patient-Reported Outcome Measurement Information System Feasible in Bundled Payment for Care Improvement in Total Hip Arthroplasty Patients?

BACKGROUND: The Patient-Reported Outcomes Measurement Information System (PROMIS) is increasingly used to assess patient health. The Bundled Payment for Care Improvement (BPCI) initiative for total hip arthroplasty (THA) was introduced to decrease costs and improve clinical care. We investigated differences between BPCI and non-BPCI THA patients and their PROMIS scores, along with its feasibility and responsiveness in these populations. METHODS: We included all consecutive patients receiving unilateral primary THA who also had preoperative and one-year postoperative PROMIS physical function (PF), PROMIS pain interference (PI), and PROMIS depression (DEP) scores. Demographics and PROMIS scores were compared. Test burden was assessed using the number of questions and time required for PROMIS completion. The minimum clinically important difference was defined as 5. Floor and ceiling effects were noted if more than 15% of patients responded with the lowest or highest possible score, respectively. Wilcoxon rank-sum test was used to compare categorical data. ANOVA was used for PROMIS comparisons. RESULTS: 290 hips (86 BPCI, 30%) were included. The BPCI cohort was older (P < .001) with a higher American Society of Anesthesiologists physical status classification system (P = .0045). There were significant differences in baseline scores of PF and DEP between BPCI and non-BPCI (P = .046 and P = .048, respectively). Both groups showed significant improvement at follow-up in all scores (all P < .001). Significantly more non-BPCI patients achieved minimum clinically important difference at follow-up in PI and PF (P = .047 and P = .023, respectively). Floor effects were identified for DEP at baseline and follow-up and for PI at follow-up only. CONCLUSION: PROMIS is feasible and time-efficient in BPCI patients undergoing primary THA. There were significant differences between BPCI and non-BPCI hips. LEVEL OF EVIDENCE: Level III.

Choices, Compromises, and Controversies in Total Knee Arthroplasty.

Although condylar total knee arthroplasty (TKA) has been performed for almost 40 years, many choices, compromises, and controversies remain. In the effort to provide optimal care and beneficial, enduring treatment for an expanding population of patients with debilitating arthritis of the knee and who are using ever-diminishing provider and financial resources, orthopaedic surgeons must carefully examine the available evidence to determine best practices. First, there is debate as to who should be a candidate for TKA. Beyond the established criteria of disease severity, should all patients who can benefit from TKA undergo the procedure, or should surgeons develop exclusion criteria based on complication risk? Current concepts for identifying and managing modifiable risk factors should be considered. Second, there is debate regarding the choice of TKA versus partial knee arthroplasty to manage unicompartmental arthritis. Third, surgeons continue to debate the ideal implant design for primary condylar TKA, whether to proceed with an anatomic approach of preserving one or both cruciate ligaments or a functional approach of resecting and substituting for the cruciate ligaments in various ways.

Patient Perceptions of the Safety of Outpatient Total Knee Arthroplasty.

BACKGROUND: Outpatient total joint arthroplasty is considered safe in a selected group of patients, based primarily on complications. However, patient perception of the safety of outpatient total joint arthroplasty is unknown. This study assesses patient perceptions of the potential benefits of and barriers to outpatient total knee arthroplasty among a cohort of patients who have recently undergone the procedure. METHODS: Patients who underwent unilateral primary total knee arthroplasty between March 1, 2017, and September 30, 2017 at our institution were given a questionnaire, in which they were asked about prior knowledge regarding outpatient total knee arthroplasty, their perceived ability to undergo the procedure as an outpatient, and their perceived risks and benefits to outpatient surgery. RESULTS: Three hundred forty-six patients completed the survey. Over 70% of patients did not think that they would be able to undergo total knee arthroplasty as an outpatient. Their primary concerns were pain, being able to go to the bathroom, and falls. CONCLUSIONS: Patients in this study largely would not feel safe undergoing total knee arthroplasty on an outpatient basis. Payers should not only take into account existing literature but also the concerns and perceived needs of patients, before encouraging widespread implementation of outpatient total knee arthroplasty.

Effect of Adductor Canal Block on Acute Perioperative Pain and Function in Total Knee Arthroplasty.

BACKGROUND: Multimodal pain management strategies are commonplace in perioperative management of total knee arthroplasty (TKA), although controversy remains regarding the role of adductor canal blocks (ACB) in this algorithm. The purpose of this study is to independently evaluate the effect of ACB on short-term postoperative outcomes including (1) length of stay (LOS), (2) postoperative narcotic utilization, and (3) function with physical therapy in the era of modern TKA. METHODS: We retrospectively identified a cohort of consecutive patients from January 2014 to January 2018 who had undergone unilateral primary TKA using a single-shot ACB in addition to a standardized multimodal pain regimen vs those who only received a multimodal pain regimen. These 2 groups were compared using independent sample t-tests with primary end points of interest being LOS, distance ambulated with therapy, and inpatient narcotic use. RESULTS: There were 624 patients in the ACB group, with a mean age of 64.5 years. The group without ACB consisted of 69 patients, with a mean age of 67.2 years. We observed no significant difference in narcotic utilization postoperatively (2.361 vs 2.097, P = .088). The ACB group ambulated significantly further with therapy (75.8 vs 59.9 ft, P = .008) and had a shorter LOS in both total hours and percentage of postoperative day 1 (%POD1) discharges (34.8 vs 40.6 hours, P = .01, 83% vs 66.6%, P = .01). CONCLUSION: ACB did not decrease postoperative pain medication utilization. The modest improvement in distance ambulated with therapy on POD1 (16 ft) and LOS (16% greater POD1 discharges) may not support the cost-effectiveness of this intervention. LEVEL OF EVIDENCE: III, Retrospective Cohort.

Effect of Low-Intensity vs Standard-Intensity Warfarin Prophylaxis on Venous Thromboembolism or Death Among Patients Undergoing Hip or Knee Arthroplasty: A Randomized Clinical Trial.

Importance: The optimal international normalized ratio (INR) to prevent venous thromboembolism (VTE) in warfarin-treated patients with recent arthroplasty is unknown. Objective: To determine the safety and efficacy of a target INR of 1.8 vs 2.5 for VTE prophylaxis after orthopedic surgery. Design, Setting, and Participants: The randomized Genetic Informatics Trial (GIFT) of Warfarin to Prevent Deep Vein Thrombosis enrolled 1650 patients aged 65 years or older initiating warfarin for elective hip or knee arthroplasty at 6 US medical centers. Enrollment began in April 2011 and follow-up concluded in October 2016. Interventions: In a 2 × 2 factorial design, participants were randomized to a target INR of 1.8 (n = 823) or 2.5 (n = 827) and to either genotype-guided or clinically guided warfarin dosing. For the first 11 days of therapy, open-label warfarin dosing was guided by a web application. Main Outcomes and Measures: The primary outcome was the composite of VTE (within 60 days) or death (within 30 days). Participants underwent screening duplex ultrasound postoperatively. The hypothesis was that an INR target of 1.8 would be noninferior to an INR target of 2.5, using a noninferiority margin of 3% for the absolute risk of VTE. Secondary end points were bleeding and INR values of 4 or more. Results: Among 1650 patients who were randomized (mean age, 72.1 years; 1049 women [63.6%]; 1502 white [91.0%]), 1597 (96.8%) received at least 1 dose of warfarin and were included in the primary analysis. The rate of the primary composite outcome of VTE or death was 5.1% (41 of 804) in the low-intensity-warfarin group (INR target, 1.8) vs 3.8% (30 of 793) in the standard-treatment-warfarin group (INR target, 2.5), for a difference of 1.3% (1-sided 95% CI, -∞ to 3.05%, P = .06 for noninferiority). Major bleeding occurred in 0.4% of patients in the low-intensity group and 0.9% of patients in the standard-intensity group, for a difference of -0.5% (95% CI, -1.6% to 0.4%). The INR values of 4 or more occurred in 4.5% of patients in the low-intensity group and 12.2% of the standard-intensity group, for a difference of -7.8% (95% CI, -10.5% to -5.1%). Conclusions and Relevance: Among older patients undergoing hip or knee arthroplasty and receiving warfarin prophylaxis, an international normalized ratio goal of 1.8 compared with 2.5 did not meet the criterion for noninferiority for risk of the composite outcome of VTE or death. However, the trial may have been underpowered to meet this criterion and further research may be warranted. Trial Registration: ClinicalTrials.gov Identifier: NCT01006733.

No impact of under-correction and joint line obliquity on clinical outcomes of total knee arthroplasty for the varus knee.

PURPOSE: It has been hypothesized that under-correction of a preoperative varus deformity may be more natural and improve outcomes after total knee arthroplasty (TKA). This study's purpose was to assess the impact of hip-knee-ankle (HKA) alignment and joint line obliquity on TKA outcomes for the varus knee. METHODS: All patients with a preoperative varus deformity received both preoperative and postoperative standing, full-length radiographs from which two independent observers performed radiographic measurements including the HKA axis and mechanical medial proximal tibial angle (mMPTA). Patients were categorized based on their HKA into neutral (0° ± 3°), mild varus (-6° to -3°), severe varus (≤ -6°), and valgus (>3°) cohorts, and separately categorized based on their mMPTA into neutral (90° ± 2°), mild varus (86°-88°), severe varus (<86°), and valgus (>92°) cohorts. RESULTS: Two hundred and fifty-six patients (mean age 63.8 ± 9.0 years, BMI 33.0 ± 6.2 kg/m2, follow-up 1.3 ± 0.6 years) were included. There was no difference in the postoperative SF-12 physical component, mental component, Oxford knee, Forgotten Joint Score, or incremental improvement in scores based on the postoperative alignment category for either the HKA or mMPTA. There was no correlation between the magnitude of change in HKA (r = 0.03-0.1) and mMPTA (r = 0.02-0.1) from preoperatively to postoperatively with clinical outcomes. CONCLUSIONS: In patients undergoing TKA for a preoperative varus deformity, a specific postoperative HKA or mMPTA alignment category was not associated with improved outcomes. Therefore, categorization of optimal postoperative alignment after TKA may not be possible as static, coronal alignment is just one of many variables that can impact clinical outcomes. Future investigations focusing on the combination of static images with dynamic examinations and ligamentous balancing may shed further insight into the controversy and importance of coronal alignment following TKA. LEVEL OF EVIDENCE: III.

The Impact of Hospital Volume on Racial Differences in Complications, Readmissions, and Emergency Department Visits Following Total Joint Arthroplasty.

BACKGROUND: Minority patients are at higher risk for complications and readmissions after total hip and knee arthroplasty. They are also more likely to undergo joint replacement in lower volume centers, which is associated with poorer outcomes. It is unknown whether these disparities simply reflect disproportionate use of lower volume centers. This study evaluates the impact of hospital volume on racial differences in outcomes following joint replacement. METHODS: Patients who underwent total hip or knee arthroplasty between 2006 and 2013 in New York and Florida were identified through the Healthcare Cost and Utilization Project State Inpatient Databases. Complications, readmissions, and emergency department (ED) visits within 90 days were compared by hospital volume. Relative risks were calculated with generalized estimating equations for risk factors associated with adverse outcomes. RESULTS: Race/ethnicity was not associated with readmission following hip replacement. Black race was associated with readmission following knee replacement (relative risk [RR] 1.16). Black race was associated with ED visits following hip replacement (RR 1.29) and knee replacement (RR 1.33). Hispanic ethnicity was associated with ED visits following knee replacement (RR 1.15), but not hip replacement. These associations did not change after adjusting for hospital volume. CONCLUSION: Adjusting for hospital volume does not alter the risk of readmissions and ED use associated with minority race/ethnicity, suggesting that hospital volume alone may be insufficient to explain racial differences in outcome.