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Purpose: This study was performed to investigate the relationship between the amount of femorotibial alignment correction and the amount of improvement of hindfoot alignment in total knee arthroplasty (TKA). Methods: A total of 159 knees undergoing TKA in 120 patients were assessed preoperatively and at 2 weeks, 1 month, 3 months and 6 months postoperatively. Standing hindfoot alignment was evaluated using the leg‐heel angle (LHA). The amount of change in hindfoot alignment was compared between patients with severe varus knee (Group 1) and those with moderate varus, neutral or valgus knee (Group 2). Results: The mean values of pre‐ and postoperative hip‐knee‐ankle (HKA) angle were −14 ± 4° and −1 ± 3° in Group 1 and −7 ± 5° and −1 ± 3° in Group 2, respectively. The differences between pre‐ and postoperative LHA were significantly larger in Group 1 than in Group 2 at 2 weeks, 1 month and 3 months postoperatively (p = 0.006, 0.001 and 0.03, respectively). At 6 months postoperatively, no differences were observed between the two groups (p = 0.31). Conclusion: The amount of change in hindfoot alignment was larger in Group 1 than in Group 2 at 2 weeks, 1 month and 3 months after TKA, but there was no significant difference between the two groups at 6 months after TKA. Level of Evidence: Prognostic Level II. [ABSTRACT FROM AUTHOR]

Background: We developed an augmented reality (AR)-based portable navigation system in which the surgeon can view the pelvic plane and placement angle of an acetabular cup on the display of a smartphone during THA.Questions/purposes: (1) Is acetabular component placement more accurate using the AR-based portable navigation system compared with the conventional freehand technique? (2) Is intraoperative measurement of placement angle more accurate when using the AR-based portable navigation system compared with a goniometer?Methods: Forty-six patients were randomly assigned to undergo acetabular cup placement during THA using the AR-based portable navigation system (AR navigation group) or placement of a mechanical alignment guide (conventional group). All surgeries were performed with the patient in the lateral decubitus position. We compared the absolute value of the difference between the targeted placement angle and postoperative measured placement angle between the groups using two types of imaging (radiography and CT).Results: In terms of radiographic inclination, the mean differences between the targeted placement angle and postoperative measured angle were smaller in the AR navigation group than in the conventional group for both radiographs and CT images (2.3° ± 1.4° versus 3.9° ± 2.4°, respectively; p = 0.009 and 1.9° ± 1.3° versus 3.4° ± 2.6°, respectively; p = 0.02). There were no differences in radiographic anteversion between the two groups. No complications were associated with the use of the AR-based portable navigation system.Conclusions: This system yielded no differences in acetabular anteversion accuracy, and no clinically important differences in acetabular inclination. Therefore, at this time we cannot recommend this device as its costs and risks cannot be justified based on the absence of a clinically meaningful difference in cup placement accuracy. Although we detected no complications, this was a small series, and this approach adds both surgical time and pins in the ilium.Level Of Evidence: Level I, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Combined intraoperative intravenous and intra-articular tranexamic acid (TXA) is 1 of the most effective administration routes to decrease the amount of perioperative blood loss during total knee arthroplasty (TKA). However, the additive effect of postoperative intravenous TXA administration remains unclear. We hypothesized that the postoperative repeated-dose intravenous administration of TXA would provide lower perioperative blood loss.Methods: We performed a double-blinded, placebo-controlled trial involving patients undergoing primary TKA. A total of 100 patients who were managed with combined intraoperative intravenous and intra-articular TXA were randomly assigned to receive 3 postoperative 1,000-mg doses of intravenous TXA (TXA group) or 3 postoperative doses of intravenous normal saline solution (placebo group) in a 1:1 ratio. The prespecified primary outcome was perioperative blood loss calculated from patient blood volume and the difference in hemoglobin from preoperatively to postoperative day 3. A post hoc power analysis showed that the number of patients allocated to either the TXA group (n = 46) or the placebo group (n = 54) possessed >80% power to detect a 200-mL difference in perioperative blood loss.Results: In the intention-to-treat analysis, we found no significant differences in perioperative blood loss between the TXA group and the placebo group through postoperative day 3 (578 ± 229 compared with 640 ± 276 mL, respectively; 95% confidence interval for the difference, -40 to 163 mL; p = 0.23). The prevalence of postoperative thrombotic events did not differ between the 2 groups (4.3% compared with 3.7%, respectively; p > 0.99).Conclusions: Postoperative intravenous TXA had no additive effect in reducing perioperative blood loss in patients receiving intraoperative combined intravenous and intra-articular TXA.Level Of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Periarticular analgesic injection (PAI) is being used more commonly for pain relief after orthopaedic surgeries. However, there is conflicting evidence regarding the effectiveness of PAI for post-THA pain relief.Questions/purposes: In a double-blind, randomized, controlled trial among patients undergoing same-day bilateral THA, with each patient serving as his or her own control, we asked: (1) Did the pain score as measured on a 100-mm VAS differ between the hips that received PAI versus placebo? (2) Were there differences in complications between the treatment and control hips in these patients?Methods: Over a 1-year period at one center, 45 patients underwent same-day bilateral THA; three were excluded for prespecified reasons, and two declined participation in this randomized, controlled trial, leaving 40 patients (80 THAs) in the study. Patients randomly received PAI in one hip and placebo in the contralateral hip; patients, surgeons, and nurses were blinded in terms of which hip received the PAI and which hip received a placebo saline injection. The PAI solution included ropivacaine, morphine hydrochloride hydrate, methylprednisolone, ketoprofen, and epinephrine. The primary outcome was the VAS for pain at rest 24 hours after THA, measured using a 100-mm horizontal VAS. The VAS score was compared between two groups and assessed to reach the reported threshold values for the minimum clinically important difference (MCID) of 20 mm for the postoperative VAS score. No patients were lost to followup, and there were no missing data for the primary outcome. Complications that occurred during the trial were recorded prospectively with emphasis on infection, wound complications, nerve palsy and allergic reactions to the injections.Results: There were no clinically important differences between hips treated with the PAI and those treated with the placebo injection at any point. The hips that received PAI had less pain than those receiving placebo 24 hours after THA (16 ± 17 mm versus 22 ± 20 mm; mean difference, 6 mm; 95% confidence interval [CI], 2-9 mm; p = 0.006), but this effect size was below the MCID of 20 mm and thus is unlikely to be clinically important. The hips that received PAI also had better VAS scores in the recovery room (38 ± 29 mm versus 52 ± 33 mm; mean difference 14 mm; 95% CI, 5-23 mm; p = 0.004) and 3 hours after THA than placebo controls (28 ± 22 mm versus 37 ± 24 mm; mean difference 9 mm; 95% CI, 2-16 mm; p = 0.010). Neither of these differences exceeded the MCID and likewise were unlikely to be clinically important. No complications, including surgical site infections, were observed in either group.Conclusions: Periarticular analgesic injection for pain control after THA did not result in a clinically important reduction in pain at any point examined. Given the expense associated with this PAI mixture and the lack of effectiveness outside this timeframe, we cannot recommend its use. Other mixtures or concentrations of drugs may be helpful in short-stay admissions for THA, but this will require further research.Level Of Evidence: Level I, therapeutic study. [ABSTRACT FROM AUTHOR]

This study was performed to examine the hypothesis that the rate of allogeneic blood transfusion in patients who did not predeposit an autologous blood transfusion before single-anesthetic bilateral total knee arthroplasty (TKA) would be noninferior to that in patients who did predeposit blood., Methods: We assessed the number of allogeneic transfusions required in 338 patients undergoing single-anesthetic bilateral TKA with a preoperative hemoglobin level of ≥11.0 g/dL. All TKAs were performed by a single surgeon according to the same operative and postoperative protocol. All patients received a combination of intravenous and intra-articular tranexamic acid. Neither a pneumonic tourniquet nor a drain was used. The difference in the risk of allogeneic transfusion between patients without and with autologous blood predeposit was compared with a noninferiority margin of 10 percentage points., Results: Allogeneic transfusion was required in 1 (0.5%) of 194 patients who predeposited autologous blood and 3 (2.1%) of 144 patients who did not predeposit blood. The difference in risk was -1.6 percentage points (95% confidence interval, -4.1 to 1.0 percentage points); the confidence interval did not include the noninferiority margin and included zero., Conclusions: In single-anesthetic bilateral TKA, allogeneic transfusion requirements in patients who did not predeposit autologous blood were noninferior to those in patients who predeposited blood., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSOA/A459)., (Copyright © 2023 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)

An augmented reality (AR)-based navigation system allows visualization of the center of the femoral head and femoral mechanical axis superimposed on the surgical field during total knee arthroplasty (TKA) and may help surgeons to improve the accuracy of distal femoral resection., Methods: First, we resected 10 femoral Sawbones specimens using the AR-based navigation system and performed computed tomography (CT) to measure the resection angle of the distal part of the femur. We calculated the absolute values of the differences between angles measured using CT images and angles displayed on the smartphone screen of the navigation system. Second, we measured coronal alignment using standing long-leg radiographs for 72 patients undergoing TKA and compared the error in the resection angle between TKA using the AR-based navigation system and that using a conventional intramedullary guide., Results: In the experimental study, the absolute values of the differences between angles measured on CT images and angles displayed using the AR-based navigation system were 0.8° ± 0.5° (range, 0.3° to 1.9°) in the coronal plane and 0.6° ± 0.5° (range, 0.0° to 1.4°) in the sagittal plane. In the clinical study, the mean absolute value of the error in coronal alignment was significantly smaller in the AR-based navigation group than the intramedullary-guide group (1.1° ± 1.0° [range, 0.0° to 3.2°] compared with 2.2° ± 1.6° [range, 0.0° to 5.5°], respectively; 95% confidence interval, 0.5° to 1.8°; p < 0.001)., Conclusions: The AR-based navigation system may enable surgeons to perform distal femoral resection more accurately than with the conventional intramedullary guide during TKA., Clinical Relevance: This study validates the use of AR technology to enhance the precision of bone resection in TKA., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSOA/A298)., (Copyright © 2021 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)

Background: We developed an augmented reality (AR)-based portable navigation system in which the surgeon can view the pelvic plane and placement angle of an acetabular cup on the display of a smartphone during THA., Questions/purposes: (1) Is acetabular component placement more accurate using the AR-based portable navigation system compared with the conventional freehand technique? (2) Is intraoperative measurement of placement angle more accurate when using the AR-based portable navigation system compared with a goniometer?, Methods: Forty-six patients were randomly assigned to undergo acetabular cup placement during THA using the AR-based portable navigation system (AR navigation group) or placement of a mechanical alignment guide (conventional group). All surgeries were performed with the patient in the lateral decubitus position. We compared the absolute value of the difference between the targeted placement angle and postoperative measured placement angle between the groups using two types of imaging (radiography and CT)., Results: In terms of radiographic inclination, the mean differences between the targeted placement angle and postoperative measured angle were smaller in the AR navigation group than in the conventional group for both radiographs and CT images (2.3° ± 1.4° versus 3.9° ± 2.4°, respectively; p = 0.009 and 1.9° ± 1.3° versus 3.4° ± 2.6°, respectively; p = 0.02). There were no differences in radiographic anteversion between the two groups. No complications were associated with the use of the AR-based portable navigation system., Conclusions: This system yielded no differences in acetabular anteversion accuracy, and no clinically important differences in acetabular inclination. Therefore, at this time we cannot recommend this device as its costs and risks cannot be justified based on the absence of a clinically meaningful difference in cup placement accuracy. Although we detected no complications, this was a small series, and this approach adds both surgical time and pins in the ilium., Level of Evidence: Level I, therapeutic study.

Although continuing antithrombotic therapy is desirable to prevent perioperative cardiovascular and cerebrovascular diseases, perioperative blood loss remains a concern in patients undergoing total knee arthroplasty. The purpose of this study was to assess the impact of continuing chronic antithrombotic therapy on blood loss and major bleeding events., Methods: We classified 201 consecutive patients undergoing total knee arthroplasty into 2 groups: (1) patients taking antiplatelet agents, vitamin K antagonists, and/or direct oral anticoagulants, referred to as the continuing antithrombotic therapy group (n = 32); and (2) patients not receiving these agents, referred to as the no antithrombotic therapy group (n = 169). During the study period, antithrombotic agents were continued perioperatively in all patients receiving antithrombotic therapy. Surgical procedures were performed without the use of a pneumatic tourniquet or drain. Screening for deep vein thrombosis was routinely performed before and after total knee arthroplasty. The total perioperative blood loss was calculated from blood volume and change in hemoglobin from preoperatively to postoperative days 1, 3, and 7., Results: The perioperative blood loss after total knee arthroplasty did not differ significantly between the continuing antithrombotic therapy group and the no antithrombotic therapy group at 1 day postoperatively (448 ± 213 compared with 495 ± 345 mL [95% confidence interval (CI) of the difference, -172 to 77 mL]; p = 0.45), 3 days postoperatively (841 ± 308 compared with 826 ± 328 mL [95% CI, -108 to 139 mL]; p = 0.81), and 7 days postoperatively (855 ± 313 compared with 861 ± 245 mL [95% CI, -122 to 108 mL]; p = 0.91). No patients in the continuing antithrombotic therapy group and 2 patients (1.2%) in the no antithrombotic therapy group had allogeneic blood transfusion (p = 1). No major bleeding events occurred in the continuing antithrombotic therapy group., Conclusions: Perioperative blood loss in patients continuing chronic antithrombotic therapy during total knee arthroplasty was not significantly different from that in patients receiving no chronic antithrombotic therapy., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence., (Copyright © 2019 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)