Does a Commercially Available Augmented Reality-based Portable Hip Navigation System Improve Cup Positioning During THA Compared With the Conventional Technique? A Randomized Controlled Study

Use of augmented reality surgical navigation reduces intraoperative fluoroscopic imaging in anterior total hip arthroplasty with equivalent accuracy for component positioning

Background

Computer-assisted surgical navigation was designed to reduce the rates of acetabular component malpositioning, a common cause for revision following primary total hip arthroplasty (THA). We compared intraoperative measures such as radiation exposure, radiographic acetabular cup placement, and outcomes of patients who underwent a THA using computer-assisted surgical navigation with augmented reality (AR) compared to those who underwent traditional manual THA with fluoroscopic assistance (FA).

Methods

We retrospectively reviewed 115 hips who underwent primary direct anterior THAs using the intraoperative AR surgical navigation system between 3/30/2021 and 12/30/2022. These were compared to a matched cohort of 115 primary THAs performed with FA through a direct anterior approach during the same time period. Patients were matched based on age, gender, American Society of Anesthesiologists score (ASA), and BMI. Goal inclination and anteversion were set to 42° (°) and 22°, respectively.

Results

THA with AR patients had decreased intraoperative radiation exposure (mean 2.0 versus 3.2 mGy, p < 0.001) and radiation time (mean 0.2 versus 0.4 min, p < 0.001). Deviation from the preoperative plan was similar between AR and FA for both radiographic inclination and anteversion. There was no difference in the operative time, estimated blood loss, or reoperations, all of which were for infection (1.7 versus 0.0 %, p = 0.5).

Conclusion

AR surgical navigation in primary THA has similar radiographic, operative and clinical results as THA with intraoperative FA. However, AR surgical navigation is associated with decreased intraoperative fluoroscopic radiation and time. Further research is needed to evaluate accuracy of acetabular component positioning and complications.

How Much Does a Computed Tomography-Based Mixed-Reality Navigation System Change Freehand Acetabular Component Position?

Background

This study evaluates how a computed tomography-based mixed-reality (MR) navigation system impacts acetabular component orientation compared to freehand positioning in total hip arthroplasty.

Methods

A series of 79 patients who underwent total hip arthroplasty utilizing a computed tomography-based MR navigation system were reviewed. The surgeon initially placed the acetabular cup freehand, attempting to achieve the preoperative plan, and this initial intraoperative orientation was recorded. The cup was then adjusted to the planned position. The difference between freehand and planned tilt-adjusted operative anteversion (OA) and inclination (OI) determined the navigation tool's impact.

Results

The mean preoperative planned OA was 30.1 ± 2.0 (range: 25, 35) degrees, and the mean freehand intraoperative OA was 30.2 ± 9.1 (range: 4, 57) degrees (P = .885), requiring a mean adjustment of 6.8 ± 5.1 (range: 0, 23) degrees. Freehand OA was corrected at least 5 degrees in 54.4% (43/79) of cases. The mean preoperative planned OI was 40.8 ± 0.6 (range: 39, 42) degrees, and the mean freehand intraoperative OI was 37.8 ± 6.6 (range: 18, 53) degrees (P < .001), requiring a mean adjustment of 5.7 ± 4.5 (range: 0, 22) degrees to achieve. Freehand OI was corrected at least 5 degrees in 43.0% (34/79) of cases.

Conclusions

Freehand acetabular component positioning in the lateral position is variable when attempting to execute patient-specific numerical cup orientation targets. Use of this navigation tool led the surgeon to correct more than 5 degrees in both OA and OI in roughly half of the hips.

Evaluating the Accuracy of a Computed Tomography-Based Mixed-Reality Navigation Tool for Acetabular Component Positioning in Total Hip Arthroplasty

BACKGROUND

Robotics and navigation systems have improved the accuracy and precision of acetabular component placement in total hip arthroplasty (THA). The purpose of this study was to determine if the intraoperative use of a novel mixed-reality (MR) navigation system resulted in accurate acetabular component placement with minimal outliers.

METHODS

A series of 79 patients who underwent THA performed by a single surgeon using a novel MR navigation system were retrospectively reviewed. The preoperative planned acetabular component operative inclination (OI) and tilt-adjusted operative anteversion (OA) were collected for each case. At the six-week follow-up, each patient underwent three-dimensional EOS imaging, which was used to measure the acetabular component placement via validated measuring software. Patients who had bilateral THAs or three-dimensional images that did not have critical bony landmarks visible for measurement were excluded from the study. Absolute error was calculated for both inclination and anteversion. Outliers were defined as any cup position that was outside a range of ± 10 degrees from the preoperatively planned target. A total of 39 patients met the inclusion criteria.

RESULTS

The mean planned OI for each patient was 40.8 (range, 40 to 41) degrees, and the mean measured postoperative OI was 40.4 (range, 37 to 46) degrees (P = 0.40), resulting in a mean absolute error of 1.8 (range, zero to five) degrees. The mean planned OA was 30.2 (range, 25 to 35) degrees, and the mean measured postoperative OA was 31.1 (range, 27 to 42) degrees (P = 0.11), resulting in a mean absolute error of 2.0 (range, zero to six) degrees. There were no outliers in either OI or OA.

CONCLUSIONS

The results of this study suggest that the use of MR navigation during THA results in accurate postoperative acetabular component inclination and anteversion relative to the preoperative plan without outliers.

The Role of Artificial Intelligence and Emerging Technologies in Advancing Total Hip Arthroplasty

Total hip arthroplasty (THA) is a widely performed surgical procedure that has evolved significantly due to advancements in artificial intelligence (AI) and robotics. As demand for THA grows, reliable tools are essential to enhance diagnosis, preoperative planning, surgical precision, and postoperative rehabilitation. AI applications in orthopedic surgery offer innovative solutions, including automated hip osteoarthritis (OA) diagnosis, precise implant positioning, and personalized risk stratification, thereby improving patient outcomes. Deep learning models have transformed OA severity grading and implant identification by automating traditionally manual processes with high accuracy. Additionally, AI-powered systems optimize preoperative planning by predicting the hip joint center and identifying complications using multimodal data. Robotic-assisted THA enhances surgical precision with real-time feedback, reducing complications such as dislocations and leg length discrepancies while accelerating recovery. Despite these advancements, barriers such as cost, accessibility, and the steep learning curve for surgeons hinder widespread adoption. Postoperative rehabilitation benefits from technologies like virtual and augmented reality and telemedicine, which enhance patient engagement and adherence. However, limitations, particularly among elderly populations with lower adaptability to technology, underscore the need for user-friendly platforms. To ensure comprehensiveness, a structured literature search was conducted using PubMed, Scopus, and Web of Science. Keywords included "artificial intelligence", "machine learning", "robotics", and "total hip arthroplasty". Inclusion criteria emphasized peer-reviewed studies published in English within the last decade focusing on technological advancements and clinical outcomes. This review evaluates AI and robotics' role in THA, highlighting opportunities and challenges and emphasizing further research and real-world validation to integrate these technologies into clinical practice effectively.

Accuracy of Acetabular Component Positioning Using a Mixed Reality-Guided Navigation System During Total Hip Arthroplasty

Background

Surgeons increasingly recognize the importance of patient-specific considerations in determining ideal cup alignments. In addition, various surgical navigation systems have been reported to improve cup placement accuracy during total hip arthroplasty (THA). Recently, a novel computed tomography (CT)-based planning and mixed-reality (MR) guidance system was developed to enable patient-specific 3-dimensional planning of the ideal cup position and further improve intraoperative achievement of the planned orientation.

Methods

This is retrospective, observational study of 40 patients (40 hips) who underwent MR-guided THA. Patient-specific CT-based surgical planning with definition of target operative anteversion and inclination of the acetabular cup in relation to the anterior pelvic plane was performed. 3D holograms of the cup and cup impactor in the selected target position were created and exported. Intraoperatively, automatic holographic registration was performed using a smart tool-based linked-paired-point matching method. Patient-specific content was displayed on a head-mounted display, and the acetabular component was inserted by matching the spatial position of the cup impactor with the hologram of the cup impactor in the target position. Postoperatively, patients underwent biplane simultaneous imaging for measurement of achieved cup alignment using a validated measurement method.

Results

Mean planned operative anteversion and inclination angles were 28.4° ± 1.6° (95% confidence interval [CI], 27.9°-28.8°) and 39.9° ± 0.3° (95% CI, 39.8°-40.0°), respectively. The mean absolute target error between preoperative target operative anteversion and the achieved operative anteversion was 0.7° ± 1.1° (95% CI, 0.3°-1.0°; range, 0°-4°). The mean absolute target error between preoperative target operative inclination and the achieved operative inclination was 1.1° ± 1.2° (95% CI, 0.7°-1.4°; range, 0°-4°).

Conclusion

Acetabular component positioning using a mixed reality guidance system during THA was highly accurate and well within the accuracy reported for other navigation systems.

Level of Evidence

Level III. See Instructions for Authors for a complete description of levels of evidence.

Interposition of the Fracture Fragment of a Vitamin E-Blended, Highly Crosslinked Polyethylene Liner After Total Hip Arthroplasty: A Case Report

This is the first case report of a vitamin E-blended polyethylene liner fracture after total hip arthroplasty. Our case highlights the importance of considering a vitamin E-blended polyethylene liner fracture, the interposition of fracture fragments between the articulating surfaces after dislocation and blocked successful reduction.

Comparison of Implant Placement Accuracy Between Manual, Robot-Assisted, Computer-Navigated, Augmented Reality Navigated, Patient-Specific Instrumentation, and Accelerometer Navigated Total Hip Arthroplasty: A Systematic Review and Network Meta-Analysis

BACKGROUND

Malpositioning of the acetabular cup during total hip arthroplasty (THA) can lead to complications. Robotic surgery and navigation techniques aim to address this issue, but there is limited evidence regarding which method can achieve better clinical outcomes. Therefore, this network meta-analysis (NMA) aimed to compare the efficacy of various navigation methods.

METHODS

This NMA of prospective randomized controlled trials compared robot-assisted systems (RAS), computer-assisted navigation systems (CAS), augmented reality-based portable navigation (AR), patient-specific instrumentation (PSI), portable accelerometer-based navigation (PN), and conventional methods (C) for THA procedures. We searched MEDLINE, EMBASE, Cochrane, Central Register of Controlled Trials, International Clinical Trials Platform Search Portal, and ClinicalTrials.gov. databases. The primary outcomes included revision surgery and postoperative clinical scores, and the secondary outcomes encompassed cup placement accuracy, acetabular cup placement outliers from the Lewinnek safe zone, surgical time, and complications. We used a Bayesian random-effects NMA, and confidence of evidence was assessed using confidence in NMA.

RESULTS

We identified 45 studies including 2,122 patients. We did not find large differences in revision surgery, clinical outcome scores, cup inclination, or anteversion angle accuracy among the modalities. AR, CAS, and PSI exhibited a lower risk of outliers from safe zones than C. In addition, RAS and CAS had a longer surgical time than C.

CONCLUSIONS

Robotic and navigation tools did not reduce the revision risk or enhance clinical outcomes. AR, CAS, PSI, and PN may decrease the risk of cup placement outliers in safe zones. However, the cup placement accuracy was equivalent, and the surgical time may be longer in RAS and CAS than in C.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Retrospective study comparing the accuracies of handheld infrared stereo camera and augmented reality-based navigation systems for total hip arthroplasty

BACKGROUND

The use of portable navigation systems (PNS) in total hip arthroplasty (THA) has become increasingly prevalent, with second-generation PNS (sPNS) demonstrating superior accuracy in the lateral decubitus position compared to first-generation PNS. However, few studies have compared different types of sPNS. This study retrospectively compares the accuracy and clinical outcomes of two different types of sPNS instruments in patients undergoing THA.

METHODS

A total of 158 eligible patients who underwent THA at a single institution between 2019 and 2022 were enrolled in the study, including 89 who used an accelerometer-based PNS with handheld infrared stereo cameras in the Naviswiss group (group N) and 69 who used an augmented reality (AR)-based PNS in the AR-Hip group (group A). Accuracy error, navigation error, clinical outcomes, and preparation time were compared between the two groups.

RESULTS

Accuracy errors for Inclination were comparable between group N (3.5° ± 3.0°) and group A (3.5° ± 3.1°) (p = 0.92). Accuracy errors for anteversion were comparable between group N (4.1° ± 3.1°) and group A (4.5° ± 4.0°) (p = 0.57). The navigation errors for inclination (group N: 2.9° ± 2.7°, group A: 3.0° ± 3.2°) and anteversion (group N: 4.3° ± 3.5°, group A: 4.3° ± 4.1°) were comparable between the groups (p = 0.86 and 0.94, respectively). The preparation time was shorter in group A than in group N (p = 0.036). There were no significant differences in operative time (p = 0.255), intraoperative blood loss (p = 0.387), or complications (p = 0.248) between the two groups.

CONCLUSION

An Accelerometer-based PNS using handheld infrared stereo cameras and AR-based PNS provide similar accuracy during THA in the lateral decubitus position, with a mean error of 3°-4° for both inclination and anteversion, though the AR-based PNS required a shorter preparation time.

Comparison between accuracy of augmented reality computed tomography-based and portable augmented reality-based navigation systems for cup insertion in total hip arthroplasty

Augmented reality (AR) has been used for navigation during total hip arthroplasty (THA). AR computed tomography (CT)-based navigation systems and AR-based portable navigation systems that use smartphones can also be used. This study compared the accuracy of cup insertion during THA using AR-CT-based and portable AR-based navigation systems. Patients with symptomatic hip disease who underwent primary THA in the supine position using both AR CT-based and portable AR-based navigation systems simultaneously between October 2021 and July 2023 were included. The primary outcome of this study was the absolute difference between cup angles in the intraoperative navigation record and those measured on postoperative CT. The secondary outcome was to determine the factors affecting the absolute value of the navigation error in radiographic inclination (RI) and radiographic anteversion (RA) of the cup, including sex, age, body mass index, left or right side, approach, and preoperative pelvic tilt. This study included 94 consecutive patients. There were 11 men and 83 women, with a mean age of 68 years. The mean absolute errors of RI were 2.7° ± 2.0° in the AR CT-based and 3.3° ± 2.4° in the portable AR-based navigation system. The mean absolute errors of RA were 2.5° ± 2.1° in the AR CT-based navigation system and 2.3° ± 2.2° in the portable AR-based navigation system. No significant differences were observed in RI or RA of the cup between the two navigation systems (RI: p = 0.706; RA: p = 0.329). No significant factors affected the absolute value of the navigation errors in RI and RA. In conclusion, there were no differences in the accuracy of cup insertion between the AR CT-based and portable AR-based navigation systems.

Measurement accuracy of the acetabular cup position using an inertial portable hip navigation system with patients in the lateral decubitus position

Accurate cup placement is critical to ensure satisfactory outcomes after total hip arthroplasty. Portable hip navigation systems are novel intraoperative guidance tools that achieve accurate cup placement in the supine position; however, accuracy in the lateral decubitus position is under debate. A new inertial portable navigation system has recently become available. The present study investigated the accuracy of measurements of the cup position in 54 patients in the lateral decubitus position using this system and compared it with that by a goniometer. After cup placement, cup abduction and anteversion were measured using the system and by the goniometer, and were then compared with postoperatively measured angles. Absolute measurement errors with the system were 2.8° ± 2.6° for cup abduction and 3.9° ± 2.9° for anteversion. The system achieved 98 and 96% measurement accuracies within 10° for cup abduction and anteversion, respectively. The system was more accurate than the goniometer for cup anteversion (p < 0.001), but not for abduction (p = 0.537). The system uses a new registration method of the pelvic reference plane and corrects intraoperative pelvic motion errors, which may affect measurement accuracy. In the present study, reliable and reproducible intraoperative measurements of the cup position were obtained using the inertial portable navigation system.

Accuracy and safety of a new robotic arm for both femoral and acetabular side in total hip arthroplasty: a cadaveric study

BACKGROUND

To investigate the accuracy and safety of a newly constructed robotic arm which can cover the whole process of THA, we performed a series of robot-assisted total hip replacement on the cadaver.

METHODS

Fifteen frozen cadaveric specimens (30 hips) were used for this study. In this investigation, united hip system and Longwell robotic-assisted system were used. The entire lower limb was CT scanned prior to surgery. The 3D model was produced based on CT data; the site of the prosthesis, including acetabular anteversion, inclination angle, and the position of femoral prosthesis, was planned. With the assistance of a robotic arm, the surgeon changed the parameters based on the preoperative plan and the actual condition during surgery, and completed the whole procedure. Following surgery, we measured the acetabular anteversion angle, acetabular inclination angle, femur anteversion angle, combined anteversion angle, stem angulation, and canal fill ratio.

RESULTS

The parameters proved that the acetabular anteversion angle was 16.85 ± 3.00°, the acetabular inclination angle was 40.38 ± 5.37°, femur anteversion angle was 15.90 ± 9.01°, combined anteversion angle was 32.75 ± 9.03°, stem angulation was 1.84 ± 0.99°, and leg length discrepancy was 2.47 ± 1.43 mm. The canal fill ratio (CFR) of femoral prosthesis of osteotomy line in sagittal section is 99.72 ± 1.54% and in coronal section is 62.94 ± 8.91%; below osteotomy line 2.5 cm in sagittal section is 100.00% and in coronal section is 81.48 ± 12.94%; below osteotomy line 7.5 cm in sagittal section is 59.51 ± 12.94% and in coronal section is 89.79 ± 11.13%; femoral shaft isthmus in sagittal section is 56.41 ± 13.80% and in coronal section is 84.95 ± 15.17%.

CONCLUSION

The accuracy and safety of this novel robotic arm are suitable for preparing both the acetabular and femoral sides, providing evidence for clinical trial.