Abstract
Purpose
This study compared the accuracy of acetabular cup installation angles in total hip arthroplasty (THA) between a CT-based augmented reality (AR) navigation system and a noninvasive AR portable navigation system used simultaneously during surgery. Both navigation systems can be used with acetabular components from multiple manufacturers.
Methods
This study included 48 hips across 44 patients who underwent primary cementless THA in the supine position. Acetabular cup placement was guided by the AR CT-based navigation system, whereas the noninvasive AR portable navigation system provided a single static measurement after cup fixation. The cohort consisted of 12 male and 36 female hips, with a mean age of 69 years and a mean body mass index (BMI) of 24 kg/m². The target angles for cup placement were 40° for radiographic inclination (RI) and 15° for radiographic anteversion (RA). Navigation errors were defined as the absolute difference between intraoperative navigation values and postoperative CT measurements and compared between groups.
Results
RI navigation errors were similar (CT-based AR group vs. noninvasive AR portable group: 2.4°±2.0° vs. 2.8°±2.4°; not significant). In contrast, RA navigation errors were significantly smaller in the CT-based AR group (2.3°±1.8°) than in the noninvasive AR portable group (3.2°±2.4°; p < 0.05). No significant factors influencing navigation errors were identified in either group.
Conclusion
In supine THA, under these static measurement conditions, RI navigation error did not differ significantly between the two systems, whereas RA navigation error was significantly greater with the noninvasive AR portable navigation system than with the AR CT-based navigation system.
Keywords: Computed tomography-based navigation, Augmented reality technology, Noninvasive navigation, Portable navigation, Total hip arthroplasty, Supine position
Introduction
Various navigation systems have been introduced in clinical practice to improve the accuracy of acetabular cup placement in total hip arthroplasty (THA). Good cup placement accuracy has been reported for several systems, including portable [1–8] and computed tomography (CT)-based [4, 7, 9–11] navigation systems. To further improve implant placement accuracy, several advanced technologies have been developed, including navigation systems using augmented reality (AR). Favourable acetabular cup placement accuracy has also been reported for a CT-based AR navigation system (HoloNavi One Navigation System; HoloNavi Medical Technology Inc., Ichinomiya, Japan) [7, 10, 12]. However, conventional navigation systems generally require the insertion of reference pins into the pelvis, which may cause complications, such as pin loosening, fracture [13], and postoperative pain or discomfort [14]. To overcome these limitations, a smartphone-based, noninvasive AR portable navigation system (Ortho Panther; Xelha-Medical Corp, Nagano, Japan) has been developed. Favourable cup placement accuracy has been reported for this noninvasive AR portable navigation system, which does not require pelvic pin insertion [15]. The functional pelvic plane is determined through the registration of the bilateral anterior superior iliac spines (ASIS) and gravity vector, thereby allowing real-time intraoperative assessments of the cup alignment. This system offers the advantages of simplicity and low invasiveness. However, the cup installation angle accuracy relative to that of CT-based navigation systems remains unclear. Therefore, this study compared acetabular cup installation angle accuracy between the AR CT-based and noninvasive AR portable navigation systems used simultaneously in the same cases. We hypothesised that the cup installation angle accuracy of the noninvasive AR portable navigation system would be inferior to that of the AR CT-based navigation system.
Materials and methods
Patient selection
Patients were included if they had symptomatic hip disease and were treated with primary cementless THA performed in the supine position under general anaesthesia using the AR CT-based and noninvasive AR portable navigation systems simultaneously between November 2024 and February 2026. The exclusion criteria were THA performed using a posterior approach, hips with high dislocation, or cases requiring subtrochanteric osteotomy. This study included 44 consecutive patients (48 hips). The patients’ demographic characteristics are presented in Table 1. The author conducted all pre-and post-operative evaluations, and two senior surgeons performed all surgeries.
Table 1.
Demographic data
| Parameters | Results |
|---|---|
| Mean age, years | 68.5 ± 8.1 |
| Sex, male: female hips | 12:36 |
| Mean body mass index, kg/m2 | 23.5 ± 3.9 |
| Primary diagnosis | |
| Osteoarthritis | 47 |
| Crowe classification | Ⅰ: 46, Ⅱ: 1, Ⅲ: 0, Ⅳ: 0 |
| Osteonecrosis of the femoral head | 1 |
| Approach | |
| ALS | 41 |
| DAA | 7 |
| Implants |
Prime (MicroPort Orthopedics Inc): 41 Plasmafit (Aesculap AG): 7 |
| ALS, anterolateral supine approach; DAA, direct anterior approach | |
Pre-operative planning
Pre-operative CT scans from the pelvis to the knee were obtained for all patients. Imaging was performed at 120 kV and 150 mA, including cases with metal artefacts. The slice thickness was ≤2.0 mm, and all images were acquired at a resolution of 512 × 512 pixels. As accurate assessments using the three-dimensional templating software ZedHip (LEXI Co., Tokyo, Japan) required a slice thickness of ≤2.0 mm, this protocol was applied in all cases. The acetabular component was pre-operatively planned at a radiographic inclination (RI) of 40° and a radiographic anteversion (RA) 15° relative to the functional pelvic plane (FPP). For the AR-CT-based navigation system, the pre-operative segmentation, implant size selection, and component positioning were performed using the ZedHip software. In contrast, the noninvasive AR portable navigation system did not require CT-based pre-operative planning.
Surgical procedures
The patient was placed in the supine position, and the hip was approached using either a direct anterior approach on a traction table or a modified Watson-Jones approach (anterolateral supine approach). The anterolateral supine approach was used in patients with severe deformities or excessive femoral anteversion. Before draping, reference markers were mounted horizontally and vertically on the operating table above the pelvis. After sterile draping, two 3.2 mm fixation pins were inserted into the iliac crest, and a pelvic marker for the AR CT-based navigation system was attached. In the AR CT-based navigation system, the FPP was defined using pre-operative CT data and registration of the bilateral ASIS. Initial paired-point and surface matching were performed by digitising 28 points within the acetabulum. Both navigation systems were used during the same procedure. The AR marker was attached to a standard cup holder using a screw, and the acetabular cup was inserted under the guidance of an AR-CT-based navigation system (Fig. 1a). After 1 mm of under-reaming, press-fit fixation without screws was achieved in all cases. The Prime cup (MicroPort Orthopedics Inc., Arlington, TN, USA) was used in 41 hips, and the Plasmafit cup (Aesculap AG, Tuttlingen, Germany) was used in seven hips. After cup insertion, the RI and RA values displayed on the AR-CT-based navigation system monitor were recorded (Fig. 1b). The coronal, sagittal, and axial tilts of the pelvis relative to the FPP were also displayed at all phases of the procedure [12]. Accordingly, the pelvic tilt angles at the time of pelvic registration and cup insertion were recorded, and changes in the pelvic tilt angles from registration to cup insertion were analysed. The AR marker was then removed from the cup holder, and the noninvasive AR portable navigation system was used for additional assessments. After launching the dedicated application, the supine mode and operative side were selected. The bilateral ASIS was registered using a probe (Fig. 2a), and the FPP was determined based on the ASIS position and gravity vector. In addition, to compare the sagittal pelvic tilt between the two systems, the APP was registered by pointing to the pubic tubercle with the probe. After completion of the pelvic registration, a marker was attached to the cup impactor, and the RI and RA values displayed in real time were confirmed and recorded while the marker was visualised using a smartphone (Fig. 2b, c). In all cases, the cup position remained unchanged throughout this process. Thus, the noninvasive AR portable navigation system provided a single static measurement after fixation and did not guide cup placement. Because acetabular cup insertion was performed under the guidance of the AR-CT-based navigation system, navigation output accuracy relative to post-operative CT measurements was evaluated rather than the intrinsic cup placement performance. Full weight-bearing on the affected side was permitted from post-operative day one.
Fig. 1.
Intra-operative use of the AR CT-based navigation system during total hip arthroplasty (a) Acetabular cup insertion under guidance of the AR CT-based navigation system. (b) Radiographic inclination (RI), radiographic anteversion (RA), and pelvic tilt angles displayed on the monitor after cup insertion
Fig. 2.
Intra-operative use of the noninvasive AR portable navigation system during total hip arthroplasty (a) Registration of the bilateral anterior superior iliac spines (ASIS) using a probe. (b) Real-time confirmation of radiographic inclination (RI) and radiographic anteversion (RA) with the marker attached to the cup impactor and visualized using the smartphone. (c) Smartphone screen showing the RI, RA, and sagittal pelvic tilt at cup insertion
Evaluation methods
Post-operative CT scans from the pelvis to the knee were obtained two weeks after surgery, and the RI and RA were measured relative to the FPP. All measurements were performed by the same observer using a three-dimensional digital templating system (ZedHip; Lexi Co., Tokyo, Japan). The accuracy of each navigation system was evaluated using navigation errors, which were calculated as the absolute differences between the intra-operative values displayed by the navigation systems and the corresponding post-operative CT measurements. Navigation errors were calculated separately and compared between the AR CT-based and noninvasive AR portable navigation systems. Potential factors affecting navigation errors were also investigated. These included the age, sex, body mass index (BMI), approach, pre-operative pelvic tilt, sagittal pelvic tilt at cup insertion in both the AR CT-based navigation system and the noninvasive AR portable navigation system, and absolute changes in pelvic angles recorded with the AR CT-based navigation system from registration to cup insertion in the coronal, sagittal, and axial planes. To assess the intra-observer reliability, one orthopaedic surgeon measured each parameter twice in ten hips at an interval of at least four weeks. The inter-observer reliability was assessed by having two orthopaedic surgeons independently measure the same parameters in ten hips. Intraclass correlation coefficients were calculated to evaluate intra- and inter-observer reliabilities.
Statistical analysis
Based on a previous study [16], a total sample size of 30 hips was required to detect a significant difference between the two systems (alpha = 0.05, power = 0.8). Statistical analyses were performed using EZR (Saitama Medical Center, Jichi Medical University, Saitama, Japan), which is a graphical user interface for R ( R Foundation for Statistical Computing, Vienna, Austria) [17]. The Wilcoxon signed-rank test was used to compare navigation errors between the AR CT-based and noninvasive AR portable navigation systems. Additional analyses were performed to investigate the factors associated with RI and RA navigation errors. The Mann-Whitney U test was used for categorical variables, including sex and surgical approach. Correlations between navigation errors and continuous variables, including age, BMI, pre-operative pelvic tilt, sagittal pelvic tilt at cup insertion, and absolute change in the pelvic angle from registration to cup insertion were analysed using the Spearman’s rank correlation coefficient. Statistical significance was set at p < 0.05.
Results
The intra-observer reliabilities were 0.993 and 0.993 for RI and RA, respectively, whereas the inter-observer reliabilities were 0.984 and 0.982 for RI and RA, respectively. The mean navigation error for RI was 2.4°±2.0° and 2.8°±2.4° in the AR CT-based and noninvasive AR portable groups, respectively. For RA, the mean navigation errors were 2.3°±1.8° and 3.2°±2.4° in the AR CT-based and noninvasive AR portable groups, respectively. No significant between-group difference in the RI navigation error (p = 0.348) was observed, whereas the RA navigation error was significantly greater in the noninvasive AR portable group (p = 0.0484). The absolute errors between the pre-operative target angles and intra-operative AR CT-based navigation values were 1.8°±1.6° and 1.4°±1.0° for RI and RA, respectively. The proportion of hips with RI navigation errors ≥ 5° was 14.6% (7/48) in both groups. The proportion of hips with RA navigation errors ≥ 5° was 10.4% (5/48) in the AR-CT-based group and 18.8% (9/48) in the noninvasive AR portable group. No hips in the AR-CT-based group showed navigation errors ≥ 10° for either RI or RA. In the noninasive AR portable group, 4.2% (2/48) of hips had RI errors ≥ 10°, and 2.1% (1/48) had RA errors ≥ 10°. No significant factors affecting the absolute navigation error were identified for the RI or RA (Table 2).
Table 2.
Univariate analysis of factors affecting the absolute values of navigation errors in RI and RA
| RI | RA | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| AR CT-based group | Noninvasive AR portable group | AR CT-based group | Noninvasive AR portable group | |||||||
| p-value | r | p-value | r | p-value | r | p-value | r | |||
| Sex | 0.905 | 0.390 | 0.751 | 0.069 | ||||||
| Approach | 0.188 | 0.793 | 0.092 | 0.129 | ||||||
| Age | 0.752 | 0.0469 | 0.877 | 0.0229 | 0.317 | −0.147 | 0.834 | −0.031 | ||
| Body mass index | 0.555 | 0.0873 | 0.473 | -0.106 | 0.243 | −0.172 | 0.775 | −0.0424 | ||
| Pre-operative pelvic tilt | 0.587 | −0.0805 | 0.275 | 0.160 | 0.259 | 0.166 | 0.726 | −0.052 | ||
| Sagittal pelvic tilt at cup insertion | 0.404 | −0.123 | 0.522 | 0.0957 | 0.294 | 0.155 | 0.954 | −0.00867 | ||
| Absolute change in pelvic angle | ||||||||||
| Coronal | 0.789 | −0.0397 | 0.477 | 0.105 | 0.412 | −0.121 | 0.954 | 0.00861 | ||
| Sagittal | 0.554 | 0.0876 | 0.535 | 0.0918 | 0.275 | 0.161 | 0.188 | −0.193 | ||
| Axial | 0.287 | −0.157 | 0.928 | 0.0135 | 0.837 | −0.0306 | 0.865 | −0.0252 | ||
RI, radiographic inclination; RA, radiographic anteversion
Discussion
To the best of our knowledge, this is the first study to compare the accuracy of intra-operative navigation measurements of acetabular cup installation angles between the AR CT-based and noninvasive AR portable navigation systems. Both systems were used simultaneously in the same cases. The most important finding was that, as hypothesised, RI navigation error did not differ significantly, whereas RA navigation error was significantly greater with the noninvasive AR portable navigation system. Because the portable system did not guide cup placement and provided a single static measurement after fixation, this study assessed navigation output accuracy rather than intrinsic cup placement performance and tested measurement capability on a static target rather than active navigation performance as used in real practice.
Although the bilateral ASIS are fixed bony landmarks that are invariant in principle, each system derived its own FPP independently using a different registration method. The AR CT-based system used pre-operative CT registered intra-operatively, whereas the portable system used percutaneous ASIS palpation after cup insertion and the gravity vector. Therefore, RI and RA discrepancies may partly reflect a difference in reference plane definition rather than a true difference in navigation accuracy.
Because the post-operative evaluation used the pre-operative CT-based reference, discrepancies between the pelvic tilt at the time of pre-operative CT acquisition and pelvic tilt during surgery could potentially contribute to errors in both systems. The AR CT-based navigation system continuously tracked pelvic motion through fixed pins, whereas the noninvasive AR portable navigation system assessed pelvic position after cup fixation without continuous intra-operative tracking. Without a continuously fixed pelvic reference, its reliability depends on the absence of pelvic micromotion between registration and measurement. During active guidance, prolonged impactor manipulation may increase pelvic micromotion or reference-plane drift. Therefore, the present protocol may underestimate the portable system’s true error in clinical use, and the reported RA navigation error may not fully represent performance under active guidance. Indeed, RA is generally considered to be more sensitive than RI to pelvic positional changes and registration errors [18–20], which may partly explain why a between-system difference was observed only for RA. In contrast, although intra-operative pelvic tilt changes were examined as possible factors affecting the navigation error, no significant associations were identified. Percutaneous ASIS registration errors may have affected the systems differently because each derived its FPP independently.
Previous studies have reported favourable accuracy for portable navigation systems in supine THA, with RI errors of 2.2°–3.7° and RA errors of 2.3°–4.3° [1–8, 16]. Similarly, CT-based navigation systems have demonstrated good accuracy, with RI errors of 1.9°–3.0° and RA errors of 1.9°–3.3° [4, 7, 9–11, 16]. Takada et al. used the same noninvasive AR-based portable navigation system and reported mean absolute errors of 2.9°±2.8° for RI and 3.4°±3.0° for RA based on post-operative radiographic assessments [15]. The results of previous studies on navigation accuracy in supine THA are summarised in Table 3. In the present study, RI and RA navigation errors of the noninvasive AR portable system were within reported ranges. However, under these static measurement conditions, its RA navigation error was greater than that of the AR CT-based system.
Table 3.
Accuracy of navigation systems in the supine position
| Absolute navigation error | ||||
|---|---|---|---|---|
| Navigation | Authors | Company | Inclination (°) | Anteversion (°) |
| Portable | Kamenaga et al. [1] | OrthAlign | 2.6 ± 2.7 | 2.8 ± 2.7 |
| Hasegawa et al. [2] | OrthAlign | 3.7 ± 2.8 | 3.0 ± 2.6 | |
| Hayashi et al. [3] | OrthAlign | 2.7 ± 2.1 | 2.7 ± 1.8 | |
| Tetsunaga et al. [4] | OrthAlign | 3.3 ± 2.4 | 3.4 ± 2.2 | |
| Hasegawa et al. [5] | Naviswiss AG | 2.8 ± 2.2 | 2.8 ± 2.0 | |
| Hayashi et al. [6] | Intellijoint Surgical | 2.8 ± 1.4 | 2.6 ± 2.0 | |
| Hayashi et al. [6] | OrthAlign | 2.8 ± 1.9 | 2.5 ± 1.9 | |
| Hasegawa et al. [7] | Zimmer Biomet | 3.3 ± 2.4 | 2.3 ± 2.2 | |
| Tachibana et al. [8] | Zimmer Biomet | 2.2 ± 1.8 | 3.8 ± 2.6 | |
| Takada et al. [15] | Xelha-Medical | 2.9 ± 2.8 | 3.4 ± 3.0 | |
| Naito et al. [16] | Smith & Nephew | 2.6 ± 2.7 | 4.3 ± 2.9 | |
| Present study | Xelha-Medical | 2.8 ± 2.4 | 3.2 ± 2.4 | |
| CT-based | Kalteis T et al. [9] | Brainlab | 3.0 ± 2.6 | 3.3 ± 2.3 |
| Tetsunaga et al. [4] | Brainlab | 2.7 ± 2.0 | 2.8 ± 2.6 | |
| Hasegawa et al. [7] | HoloNavi Medical Technology | 2.7 ± 2.0 | 2.5 ± 2.1 | |
| Hasegawa et al. [10] | HoloNavi Medical Technology | 2.5 ± 1.7 | 2.5 ± 2.2 | |
| Tachibana et al. [11] | Stryker | 2.4 ± 2.5 | 2.4 ± 2.0 | |
| Naito et al. [16] | HoloNavi Medical Technology | 1.9 ± 1.2 | 1.9 ± 1.4 | |
| Present study | HoloNavi Medical Technology | 2.4 ± 2.0 | 2.3 ± 1.8 | |
| Data are shown as mean±standard deviation | ||||
Conventional navigation systems generally require the insertion of pelvic reference pins, and potential complications include pin loosening, fracture [13], and short-term pain or discomfort [14]. In contrast, the noninvasive AR portable navigation system does not require pre-operative CT-based planning or pelvic pin insertion and therefore offers potential advantages in terms of simplicity and low invasiveness. Therefore, navigation systems should be evaluated in terms of not only accuracy but also invasiveness and ease of use. Errors in RA may influence iliopsoas impingement [21] and dislocation [22] and therefore have a greater impact on post-operative stability than errors in RI [23]. However, the observed between-system difference should be interpreted cautiously because it may partly reflect the asymmetric testing protocol rather than a genuine, generalisable difference in navigation accuracy.
This study had several limitations. First, the follow-up period was short, and clinical or functional outcomes could not be evaluated. Therefore, it remains unclear whether the differences in RI and RA errors observed in this study will translate into long-term clinically meaningful differences as perceived by patients. Second, the post-operative evaluation was performed using CT, which is associated with greater radiation exposure and higher costs than conventional radiography [24]. Third, full weight-bearing was permitted from post-operative day one, whereas post-operative CT was performed two weeks postoperatively. Despite stable press-fit fixation, slight cup displacement or angular changes cannot be excluded. Fourth, because each system derived its FPP independently, RI and RA discrepancies may partly reflect reference-plane differences rather than true differences in navigation accuracy. Fifth, the AR CT-based navigation system was always used first for guidance and the noninvasive AR portable navigation system second for a single static measurement. This fixed order may have introduced systematic bias against the portable system. Sixth, without a continuously fixed pelvic reference, this protocol may underestimate the portable system’s true error from pelvic micromotion or reference-plane drift during active guidance. Seventh, patients with severe deformities such as Crowe type IV hips were not included, and the present findings may not be directly generalisable to such cases. Further studies with longer follow-up periods are required to clarify the clinical usefulness of these navigation systems.
Conclusion
In supine THA, under these static measurement conditions, RI navigation error did not differ significantly between the two systems, whereas RA navigation error was significantly greater with the noninvasive AR portable navigation system than with the AR CT-based navigation system.
Author contributions
G.K.: collected the data, performed the measurement and analysis, participated in the study design and drafted the manuscript. Y.N., S.T., and H.U.: designed the study, edited the manuscript. M.H.: participated in the study design, supervised the analysis and helped to draft the manuscript. All authors read and approved the final manuscript.
Data availability
The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.
Declarations
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Kamenaga T, Hayashi S, Hashimoto S, Matsumoto T, Takayama K, Fujishiro T, Hiranaka T, Niikura T, Kuroda R (2019) Accuracy of cup orientation and learning curve of the accelerometer-based portable navigation system for total hip arthroplasty in the supine position. J Orthop Surg (Hong Kong) 27(2):2309499019848871. 10.1177/2309499019848871 [DOI] [PubMed] [Google Scholar]
- 2.Hasegawa M, Naito Y, Tone S, Wakabayashi H, Sudo A (2021) Accuracy of acetabular cup insertion in an anterolateral supine approach using an accelerometer-based portable navigation system. J Artif Organs 24(1):82–89. 10.1007/s10047-020-01206-8 [DOI] [PubMed] [Google Scholar]
- 3.Hayashi S, Hashimoto S, Takayama K, Matsumoto T, Kamenaga T, Fujishiro T, Hiranaka T, Niikura T, Kuroda R (2020) Evaluation of the accuracy of acetabular cup orientation using the accelerometer-based portable navigation system. J Orthop Sci 25(4):612–617. 10.1016/j.jos.2019.09.012 [DOI] [PubMed] [Google Scholar]
- 4.Tetsunaga T, Yamada K, Tetsunaga T, Sanki T, Kawamura Y, Ozaki T (2020) An accelerometer-based navigation system provides acetabular cup orientation accuracy comparable to that of computed tomography-based navigation during total hip arthroplasty in the supine position. J Orthop Surg Res 15(1):147. 10.1186/s13018-020-01673-y [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Hasegawa M, Naito Y, Tone S, Sudo A (2022) Accuracy of a novel accelerometer-based navigation (Naviswiss) for total hip arthroplasty in the supine position. BMC Musculoskelet Disord 23(1):537. 10.1186/s12891-022-05495-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Hayashi S, Kuroda Y, Nakano N, Matsumoto T, Kamenaga T, Maeda T, Kuroda R (2023) Comparing the accuracy of three-dimensional mini-optical portable navigation and accelerometer-based portable navigation system for acetabular cup placement during total hip arthroplasty. Arch Orthop Trauma Surg 143(7):3759–3766. 10.1007/s00402-022-04583-2 [DOI] [PubMed] [Google Scholar]
- 7.Hasegawa M, Naito Y, Tone S, Sudo A (2024) Comparison between accuracy of augmented reality computed tomography-based and portable augmented reality-based navigation systems for cup insertion in total hip arthroplasty. Sci Rep 14(1):8332. 10.1038/s41598-024-59115-2 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Tachibana T, Katagiri H, Ogawa T, Saito R, Jinno T (2025) Augmented reality-based portable navigation improves accuracy of cup placement in total hip arthroplasty with a short learning curve. BMC Musculoskelet Disord 26(1):1121. 10.1186/s12891-025-09446-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Kalteis T, Handel M, Bäthis H, Perlick L, Tingart M, Grifka J (2006) Imageless navigation for insertion of the acetabular component in total hip arthroplasty: is it as accurate as CT-based navigation? J Bone Joint Surg Br 88(2):163–167. 10.1302/0301-620x.88b2.17163 [DOI] [PubMed] [Google Scholar]
- 10.Hasegawa M, Naito Y, Tone S, Sudo A (2023) Accuracy of augmented reality with computed tomography-based navigation in total hip arthroplasty. J Orthop Surg Res 18(1):662. 10.1186/s13018-023-04155-z [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Tachibana T, Katagiri H, Ogawa T, Koyano G, Jinno T (2025) Enhancing the accuracy of cup placement in total hip arthroplasty using CT-based navigation by a trainee surgeon: a retrospective cohort study. BMC Musculoskelet Disord 26(1):262. 10.1186/s12891-025-08493-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Naito Y, Hasegawa M, Tone S, Wakabayashi H, Sudo A (2024) Accuracy of cup placement and pelvic motion in total hip arthroplasty in the lateral decubitus position using a new computed tomography-based navigation system with augmented reality technology. Arch Orthop Trauma Surg 144(5):2381–2389. 10.1007/s00402-024-05284-8 [DOI] [PubMed] [Google Scholar]
- 13.Tachibana T, Katagiri H, Watanabe T, Saito R, Jinno T (2025) Insufficiency Fractures of the Iliac Crest Following Robot-Assisted Total Hip Arthroplasty: A Report of Two Cases. Cureus 17(7):e87358. 10.7759/cureus.87358 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Lambers AP, Salim XG, Jennings R, Bucknill AT (2018) Morbidity and Safety of Iliac Crest Reference Array Pins in Navigated Total Hip Arthroplasty: A Prospective Cohort Study. J Arthroplasty 33(5):1557–1561. 10.1016/j.arth.2017.12.032 [DOI] [PubMed] [Google Scholar]
- 15.Takada R, Watanabe N, Miyatake K, Sugita N, Yoshii T, Koga H (2025) Accuracy of cup positioning of a non-invasive augmented reality-based navigation system for total hip arthroplasty in the supine position. Arthroplasty 7(1):44. 10.1186/s42836-025-00327-w [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Naito Y, Tone S, Kobayashi G, Hasegawa M (2026) Comparison of accuracy between Navbit Sprint and AR-CT-based navigation in total hip arthroplasty. Sci Rep Epub ahead print. 10.1038/s41598-026-53773-0 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Kanda Y (2013) Investigation of the freely available easy-to-use software ‘EZR’ for medical statistics. Bone Marrow Transpl 48(3):452–458. 10.1038/bmt.2012.244 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Sendtner E, Schuster T, Worner M, Kalteis T, Grifka J, Renkawitz T (2011) Accuracy of acetabular cup placement in computer-assisted, minimally-invasive THR in a lateral decubitus position. Int Orthop 35(6):809–815. 10.1007/s00264-010-1042-4 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Asai H, Takegami Y, Seki T, Ishiguro N (2021) Pelvic Tilt Reduces the Accuracy of Acetabular Component Placement When Using a Portable Navigation System: An In Vitro Study. Arthroplast Today 7:177–181. 10.1016/j.artd.2020.12.012 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Tamaki Y, Goto T, Wada K, Omichi Y, Hamada D, Sairyo K (2024) Robotic arm-assisted total hip arthroplasty via a minimally invasive anterolateral approach in the supine position improves the precision of cup placement in patients with developmental dysplasia of the hip. J Orthop Sci 29(2):559–565. 10.1016/j.jos.2023.01.012 [DOI] [PubMed] [Google Scholar]
- 21.Ueno T, Kabata T, Kajino Y, Inoue D, Ohmori T, Tsuchiya H (2018) Risk Factors and Cup Protrusion Thresholds for Symptomatic Iliopsoas Impingement After Total Hip Arthroplasty: A Retrospective Case-Control Study. J Arthroplasty 33(10):3288–3296e1. 10.1016/j.arth.2018.05.017 [DOI] [PubMed] [Google Scholar]
- 22.Seagrave KG, Troelsen A, Malchau H, Husted H, Gromov K (2017) Acetabular cup position and risk of dislocation in primary total hip arthroplasty. Acta Orthop 88(1):10–17. 10.1080/17453674.2016.1251255 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Murphy WS, Yun HH, Hayden B, Kowal JH, Murphy SB (2018) The Safe Zone Range for Cup Anteversion Is Narrower Than for Inclination in THA. Clin Orthop Relat Res 476(2):325–335. 10.1007/s11999.0000000000000051 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Brenner DJ, Hall EJ (2007) Computed tomography–an increasing source of radiation exposure. N Engl J Med 357(22):2277–2284. 10.1056/nejmra072149 [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.