Does Augmented Reality-based Portable Navigation Improve the Accuracy of Cup Placement in THA Compared With Accelerometer-based Portable Navigation? A Randomized Controlled Trial

Augmented Reality- vs Accelerometer-Based Portable Navigation System to Improve the Accuracy of Acetabular Cup Placement During Total Hip Arthroplasty in the Lateral Decubitus Position.

This study compared the accuracy of three dimensional (3D) mini-optical navigation and accelerometer-based portable navigation systems for cup positioning during a total hip arthroplasty (THA) in the supine position. This retrospective cohort study assessed data for 77 hips using 3D mini-optical navigation (n = 37) and accelerometer-based portable navigation (n = 40). The patients underwent THA through the mini-anterolateral approach in the supine position using a portable navigation system. We assessed the preoperative target angles, recorded intraoperative cup angles, postoperative CT imaging angles, cup angle measurement errors, and other clinical parameters. The mean absolute differences in radiographic inclination were similar between 3D mini-optical navigation and accelerometer-based portable navigation systems during THA in the supine position (2.8° ± 1.7° vs 2.8° ± 1.9°, p = 0.637). The mean absolute differences in radiographic anteversion were also similar (2.6° ± 2.3° vs 2.5° ± 1.9°, p = 0.737). Cup malalignment (absolute difference of inclination or anteversion between postoperative CT and preoperative target angle of > 5°) was significantly associated with body mass index (BMI) in accelerometer-based portable navigation but not in 3D mini-optical navigation. This is the first study to compare the accuracy of cup positioning between 3D mini-optical and accelerometer-based navigations in THA in the supine position. Both portable navigation systems accurately identified the orientation of cup placement. The accuracy of 3D mini-optical navigation is not affected by high BMI and may be preferred over other options in such patients.

This study aimed to examine the accuracy of tibial implant alignment using an accelerometer-based portable navigation system in unicompartmental knee arthroplasty (UKA). This retrospective matched case-control study reviewed 51 UKAs performed using an accelerometer-based portable navigation system, matched with 51 UKAs performed using conventional extramedullary rods. Coronal alignment and posterior slope of the tibial implant were measured on postoperative radiographs, and differences from preoperative planning were examined. Outliers and accuracy of tibial implant alignment were compared between the portable navigation and conventional groups using Fisher's exact test and Mann-Whitney U test, respectively. In the portable navigation group, 100% of the implants were aligned within 3.0° of both target coronal and sagittal implant alignment. In the conventional group, 76.5% and 88.2% of the implants were within 3.0° of both target coronal and sagittal implant alignment. Statistical analysis revealed that outliers of coronal and sagittal alignment were significantly less in the portable navigation group than in the conventional group (P < 0.05). In addition, the absolute value difference between postoperative measurement and preoperative planning of both coronal and sagittal alignment was significantly smaller in the portable navigation group than in the conventional group (P < 0.05). The portable navigation system improved the accuracy of tibial implant alignment in UKA. We found that 100% of the implants were aligned within 3.0° of both target coronal and sagittal implant alignment. The portable navigation system decreased the outliers of tibial coronal and sagittal alignment. Retrospective case-control study, Level III.

Accelerometer-based portable navigation systems in supine total hip arthroplasty (THA) have been developed, but there are no reports on the accuracy of cup placement. We aimed to investigate and compare the accuracy of the accelerometer-based portable navigation system versus the acetabular alignment guide placed on the pelvis in THA using the direct anterior approach (DAA). Both devices tracked changes in the pelvic position. In this single-centre, retrospective study, we reviewed 115 hips in 113 patients who underwent primary THA via the DAA using an accelerometer-based portable navigation system in the supine position (portable navigation group) and 106 hips in 101 patients who underwent THA using an acetabular alignment guide (alignment guide group) as controls. Hips were evaluated postoperatively using computed tomography to measure cup orientation. The accuracy of cup orientation was compared between the 2 groups. Absolute values of inclination error were 3.1° ± 2.2° and 2.9° ± 2.3° (p = 0.708) in the portable navigation and alignment guide groups and those of anteversion error were 2.8° ± 2.3° and 3.7° ± 2.7°, respectively (p = 0.005). The number of cups placed within 10° of error was 98.3% and 96.2% in the portable navigation and alignment guide groups, respectively (p = 0.304). The portable navigation group had significantly more hips (72.2%) placed within a 5° margin of error than did the alignment guide group (56.6%) (p = 0.016). High accuracy in cup placement was achieved using accelerometer-based portable navigation in supine THA. Using a navigation system may contribute to improved long-term outcomes.

Background Navigation systems, including portable navigation systems, used for total hip arthroplasty (THA) are useful for achieving higher cup alignment accuracy. NAVBIT, a newly available portable navigation system, uses a unique registration method, the table tilt registration. However, its accuracy is unclear. This retrospective study aimed to investigate whether THA with a portable navigation system in the lateral position with the flip technique is more accurate than THA with a cup goniometer in the supine or lateral positions. Methodology This study included 96 consecutive patients (77 women, 19 men) who underwent primary cementless THA using either a portable navigation system in the lateral position with the flip technique or a cup goniometer in the supine or lateral positions. The average age of the patients was 66.8 years (range = 29-91) and the average body mass index was 24.6 kg/m2 (range = 17.5-39.9). The accuracy of cup orientation was compared among the three groups. Results The absolute values of the difference in cup inclination and anteversion with the NAVBIT (2.1 ± 1.7°, 2.0 ± 1.4°) were smaller than that with the cup goniometer in the supine (3.4 ± 2.4°, 3.4 ± 2.2°) and lateral decubitus positions (3.4 ± 2.5°, 5.0 ± 3.5°). Overall, 91%, 64.5%, and 56.3% were within 5° of the target angles in the navigation, supine goniometer, and lateral goniometer groups, respectively. Conclusions The accuracy of cup alignment with the portable navigation system using the flip technique was significantly higher than that with the cup goniometer in the supine and lateral decubitus positions.

There is a need for new devices to improve the accuracy of implantation in unicompartmental knee arthroplasties (UKAs). The accelerometer-based portable navigation system is expected to improve this accuracy. This study aimed to compare the accuracy of UKAs performed by the portable navigation system with that of the conventional method, and to investigate whether the portable navigation system can complement the surgeon's experience. The study comprised of 80 Oxford UKAs. Knees were divided into two groups based on the method of tibial osteotomy: the conventional group (37 UKAs performed by an experienced surgeon using the extra-medullary guide) and the portable navigation group (43 UKAs performed by 2 unaccustomed surgeons using the navigation system). The absolute error from the target angle on the coronal and sagittal plane was measured on whole lower leg X-ray. The incidence of outliers (> 3°) was compared between the groups using Fisher's exact probability test. The incidences of outliers on the coronal plane were 41.0% (15 of 37 knees) in the conventional group and 9.3% (4 of 43 knees) in the portable navigation group (p < 0.0001). The incidences of outliers on the sagittal plane were 13.5% (5 of 37 knees) in the conventional group and 14.0% (6 of 43 knees) in the portable navigation group (p = 0.3772). This is the first report on the usefulness of an accelerometer-based portable navigation system in UKA. The use of this system improves the accuracy of implantation of the tibial component beyond the experience of the surgeon. Retrospective comparative study, Level III.

No studies have compared the accuracy of acetabular cup placement in total hip arthroplasty (THA) in the supine and lateral decubitus positions using the same portable navigation system. Thus, this study aimed to compare the accuracy of acetabular cup placement using a new accelerometer-based portable navigation system combined with an infrared stereo camera and inertial measurement unit between the supine and lateral decubitus positions. This retrospective study compared 45 THAs performed in the supine position (supine group) and 44 THAs performed in the lateral decubitus position (lateral group) using the same portable navigation system. The primary outcome was the absolute errors of cup placement angles, defined as the absolute values of the differences between cup radiographic inclination and anteversion angles displayed on the navigation system and those measured on postoperative computed tomography images. No significant difference in the median absolute error of the cup inclination angle (supine group 1.7° [interquartile range 0.8°-3.1°] vs. lateral group 2.1° [interquartile range 1.0°-3.7°]; p = 0.07) was found between the two groups. Similarly, no significant difference in the median absolute error of the anteversion angle (supine group 1.9° [interquartile range 0.8°-3.4°] vs. lateral group 2.1° [interquartile range 0.9°-3.1°]; p = 0.42) was found. This new accelerometer-based portable navigation system may provide high accuracy of the cup placement in THA in the lateral decubitus and supine positions.

Total hip arthroplasty (THA) using a portable navigation system (PNS) incurs costs per procedure. However, it does not require a large console. This study aimed to compare the accuracy of acetabular cup placement using a pelvic alignment guide (PAG) attached to the pelvis and an accelerometer-based PNS in THA performed in the lateral decubitus position. We retrospectively analyzed 100 hips that underwent primary THA in the lateral decubitus position between July 2018 and January 2021. The PAG was used in 50 hips, whereas the PNS was used in the other 50. Cup placement accuracy was measured using postoperative computed tomography scans, comparing errors in inclination and anteversion angles. The surgical time, blood loss, and complications were recorded. The follow-up period was at least 2 years in all cases. The mean absolute error of the inclination angle was similar between the groups (the PAG group: 3.7° ± 2.3° [range, 0.0-9.0]; the PNS group: 3.7° ± 2.3° [range, 0.2-10.5], p = 0.705). The mean absolute error of the anteversion angle was significantly smaller in the PAG group than in the PNS group (3.0° ± 2.4° [range, 0.0-9.7] vs. 6.5° ± 4.8° [range, 0.3-17.3], p < 0.001). The PAG group had a higher proportion of hips within 5° and 10° of the target angle (64 vs. 42%, P = 0.028, and 100 vs. 74%, p < 0.001, respectively). The PNS group had six hips with anteversion errors of 15° or more. Surgical time and blood loss were lower in the PAG group. The PNS group had one dislocation, whereas the PAG group did not. The accelerometer-based PNS did not demonstrate superior cup alignment accuracy compared to the PAG in THA performed in the lateral decubitus position. This finding informs surgeons that computer-assisted surgery is not necessarily superior to conventional THA using a PAG.

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. (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? 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). 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. 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 I, therapeutic study.

Advanced cardiac life support (ACLS) skills are essential for nurses. During the COVID-19 pandemic, augmented reality (AR) technologies were incorporated into medical education to increase learning motivation and accessibility. This study aims to determine whether AR for educational applications can significantly improve crash cart learning, learning motivation, cognitive load, and system usability. It focused on a subgroup of nurses with less than 2 years of experience. This randomized controlled trial study was conducted in a medical center in southern Taiwan. An ACLS cart training course was developed using AR technologies in the first stage. Additionally, the efficacy of the developed ACLS training course was evaluated. The AR group used a crash cart learning system developed with AR technology, while the control group received traditional lecture-based instruction. Both groups were evaluated immediately after the course. Performance was assessed through learning outcomes related to overall ACLS and crash cart use. The Instructional Materials Motivation Survey, System Usability Scale, and Cognitive Load Theory Questionnaire were also used to assess secondary outcomes in the AR group. Subgroup analyses were performed for nurses with less than 2 years of experience. All 102 nurses completed the course, with 43 nurses in the AR group and 59 nurses in the control group. The AR group outperformed the control group regarding overall ACLS outcomes and crash cart learning outcomes (P=.002; P=.01). The improvement rate was the largest for new staff regardless of the overall learning effect and the crash cart effect. Subgroup analysis revealed that nurses with less than 2 years of experience in the AR group showed more significant improvements in both overall learning (P<.001) and crash cart outcomes (P<.001) compared to their counterparts in the control group. For nurses with more than 2 years of experience, no significant differences were found between the AR and control groups in posttraining learning outcomes for the crash cart (P=.32). The AR group demonstrated high scores for motivation (Instructional Materials Motivation Survey mean score 141.65, SD 19.25) and system usability (System Usability Scale mean score 90.47, SD 11.91), as well as a low score for cognitive load (Cognitive Load Theory Questionnaire mean score 15.42, SD 5.76). AR-based learning significantly improves ACLS knowledge and skills, especially for nurses with less experience, compared to traditional methods. The high usability and motivational benefits of AR suggest its potential for broader applications in nursing education. ClinicalTrials.gov NCT06057285; https://clinicaltrials.gov/ct2/show/NCT06057285.

Evaluation of the accuracy of acetabular cup orientation using the accelerometer-based portable navigation system

The accuracy of acetabular cup placement using conventional portable imageless navigation systems in total hip arthroplasty (THA) in the lateral decubitus position remains challenging. Several novel portable imageless navigation systems have been developed recently to improve cup placement accuracy in THA. This study compared the accuracy of acetabular cup placement using a conventional accelerometer-based portable navigation (c-APN) system and a novel accelerometer-based portable navigation (n-APN) system during THA in the lateral decubitus position. This retrospective cohort study compared 45 THAs using the c-APN and 45 THAs using the n-APN system. The primary outcomes were the absolute errors between the intraoperative and postoperative values of acetabular cup radiographic inclination and anteversion angles and the percentage of cases with absolute errors within 5°. Intraoperative values were shown on navigation systems, and postoperative measurements were conducted using computed tomography images. The median absolute errors of the cup inclination angles were significantly smaller in the n-APN group than in the c-APN group (3.9° [interquartile range 2.2°-6.0°] versus 2.2° [interquartile range 1.0°-3.3°]; P = 0.002). Additionally, the median absolute errors of the cup anteversion angles were significantly smaller in the n-APN group than in the c-APN group (4.4° [interquartile range 2.4°-6.5°] versus 1.9° [interquartile range 0.8°-2.7°]; P < 0.001). Significant differences were observed in the percentage of cases with absolute errors within 5° of inclination (c-APN group 67% versus n-APN group 84%; P = 0.049) and anteversion angles (c-APN group 62% versus n-APN group 91%; P = 0.001). The n-APN system improved the accuracy of the cup placement compared to the c-APN system for THA in the lateral decubitus position.

ObjectiveDistraction osteogenesis is a primary treatment for severe mandibular hypoplasia. Achieving the ideal mandible movement direction through precise distraction vector control is still a challenge in this surgery. Therefore, the aim of this study was to apply Optical See-Through (OST) Augmented Reality (AR) technology for intraoperative navigation during mandibular distractor installation and analyze the feasibility to evaluate the effectiveness of AR in a phantom experiment.MethodsPhantom was made of 3D-printed mandibular models based on preoperative CT scans and dental arch scans of real patients. Ten sets of 3D-printed mandible models were included in this study, with each set consisting of two identical mandible models assigned to the AR group and free-hand group. 10 sets of mandibular distraction osteogenesis surgical plans were designed using software, and the same set of plans was shared between the AR and free-hand groups. Surgeons performed bilateral mandibular distraction osteogenesis tasks under the guidance of AR navigation, or the reference of the preoperative surgical plan displayed on the computer screen. The differences in angular errors of distraction vectors and the distance errors of distractor positions under the guidance of the two methods were analyzed and compared.Results40 distractors were implanted in both groups, with 20 cases in each. In intra-group comparisons between the left and right sides, the AR group exhibited a three-dimensional spatial angle error of 1.88 (0.59, 2.48) on the left and 2.71 (1.33, 3.55) on the right, with P = 0.085, indicating no significant bias in guiding surgery on both sides of the mandible. In comparisons between the AR group and the traditional free-hand (FH) group, the average angle error was 1.94 (1.30, 2.93) in the AR group and 5.06 (3.61, 9.22) in the free-hand group, with P < 0.0001, resulting in a 61.6% improvement in accuracy. The average displacement error was 1.53 ± 0.54 mm in the AR group and 3.56 ± 1.89 mm in the free-hand group, with P < 0.0001, indicating a 57% improvement in accuracy.ConclusionAugmented Reality technology for intraoperative navigation in mandibular distraction osteogenesis is accurate and feasible. A large randomized controlled trial with long-term follow-up is needed to confirm these findings.Trial RegistrationThe project has been registered with the Chinese Clinical Trial Registry, with registration number ChiCTR2300068417. Date of Registration: 17 February 2023.

Portable navigation systems have been developed for use in total hip arthroplasty (THA) in recent years. Although intraoperative registration in the lateral decubitus position or the supine position is need to create the three-dimensional coordinate system, it is not clear which position is appropriate. The purpose of this study was to assess the accuracy of cup placement in primary THA in the lateral decubitus position using an image-free handheld navigation device with registration in the lateral decubitus or the supine position, and clarify which position is appropriate. This retrospective study included 129 consecutive cementless THAs performed using an image-free handheld navigation device in the lateral decubitus position. Registration in the first 68 hips was performed in the lateral decubitus position and the last 61 hips was performed in the supine position. Postoperative cup radiographic inclination and radiographic anteversion were assessed, and the accuracy was compared between the two groups. The mean absolute errors of the postoperative measured inclination and anteversion from the target angles were 3.9° ± 2.2° and 4.8° ± 3.5° in the lateral group and 2.9° ± 2.7° and 3.2° ± 2.7° in the supine group (p < 0.05). The percentage of cups inside Lewinnek’s safe zone was 94% in the lateral group and 95% in the supine group (ns). The mean absolute values of navigation error in inclination and anteversion were 3.1° ± 2.1° and 4.2° ± 2.8° in the lateral group and 2.3° ± 2.0° and 3.1° ± 2.4° in the supine group (p < 0.05 and p < 0.05). Registration in the supine position improved the accuracy of cup insertion compared with the lateral decubitus position in THA using an image-free handheld navigation device in the lateral decubitus position.

Implant alignment is an important factor affecting clinical results associated with total knee arthroplasty (TKA). No report exists showing the utility of an accelerometer-based portable navigation system among patients with marked femoral bowing. The aim of this study was to evaluate the accuracy of a portable navigation system for implant alignment in Asian patients with marked femoral bowing. The authors evaluated 142 consecutive TKAs performed for primary osteoarthritis since July 2013. A portable navigation system was used in 67 knees, and a conventional jig was used in 75 knees. The authors measured the mechanical axis and femoral/tibial component alignments on long-leg radiographs obtained 2 weeks after TKA. In addition, coronal bowing of the lower limb was evaluated. The results were analyzed in the general and marked femoral bowing subgroups. There were no significant differences between the 2 groups for demographic data. The rates of femoral component outliers in the coronal plane for the navigation system and conventional technique were 1.5% and 13.3% (P=.01), respectively. Marked femoral bowing was observed in 73 knees. In the subgroup of patients with marked femoral bowing, femoral coronal alignment and its outliers were more accurate in the navigation group (0%) than in the conventional group (16.2%) (P=.025). This is the first report to show the utility of an accelerometer-based portable navigation system for accurate prosthetic alignment among Asian patients with marked femoral bowing. The navigation system decreased outliers in coronal alignment of the femur, even in cases of marked femoral bowing, but did not increase complications. [Orthopedics. 2017; 40(3):e465-e472.].