Abstract
Background
Slipped Capital Femoral Epiphysis (SCFE), is one of the most common hip disorders in adolescents, and is treated surgically by performing an Imhäuser osteotomy. The use of 3D printed guides has shown promise in improving the accuracy of the osteotomy. However, misplacement of the guide may limit the improvement. Therefore, the aim of this study was to investigate, postoperatively, the degree of malalignment of 3D printed guides compared to the 3D planning.
Methods
Patients who underwent surgery between April 2018 and October 2022 and underwent postoperative CT were included in this study. The preoperative CT was used for 3D planning of surgical treatment using 3D printed patient-specific guides and plates. The positioning error of the femoral head and of the patient-specific guide and plate was quantified by analysing the postoperative CT scans using custom software.
Results
Five SCFE patients were included in the study. Femoral head malalignment improved from 16 to 40 mm preoperatively to 11–17 mm postoperatively. Rotational malalignment improved from 29–63⁰ preoperatively to 15–31⁰ postoperatively. Residual error was mostly attributed to plate malposition, with residual translation in the range of 3–13 mm and rotation of 8–28⁰.
Conclusion
Although the postoperative position improved after surgery with 3D printed surgical guides and plates, there was a residual deviation from the planned position persisted. Further research is recommended to improve the design, accuracy of guide placement and surgery in this anatomically challenging region.
Supplementary Information
The online version contains supplementary material available at 10.1186/s13018-024-05235-4.
Keywords: 3D planning; 3D printed surgical guide; Imhäuser osteotomy; Slipped capital femoral epiphysis, Patient-specific, position accuracy.
Background
Slipped Capital Femoral Epiphysis (SCFE), one of the most common hip disorders in adolescents, occurs predominantly found in peripubertal children. It is a condition characterised by the movement of the femoral neck and shaft relative to the femoral head at the growth plate. Specifically, the proximal femoral neck and shaft move forward and rotate outward while the femoral head remains in the acetabulum [1]. The incidence of SCFE ranges from a low of 0.22 cases per 100,000 in eastern Japan to a high of 17.15 cases per 100,000 in the northeastern United States [2]. Patients with SCFE require some form of conventional treatment to either stabilise the slippage non-operatively or correct it surgically [3]. In the Netherlands alone, 11.6 surgical procedures are performed per 100,000 children aged 5 to 19 years [1].
SCFE is treated by surgery with the initial aim of stabilising the femoral head to prevent further dislocation of the physis. This is usually achieved by placing a single cannulated screw in the proximal femur. The ideal position of the single screw is in the centre of the neck and perpendicular to the growth plate [9]. If the slip is unstable, indicating that the patient has severe hip pain that does not allow gait, realignment of the proximal femur to approximate normal anatomy may be considered prior to stabilisation [4]. Realignment is achieved by reconstructive proximal femoral osteotomies to correct the position of the femur and reduce hip varus, extension and external rotation, most commonly by intertrochanteric osteotomies as described by Southwick, Imhäuser or Dunn’s procedure [5–9].
Realignment by intertrochanteric osteotomy is preceded by planning, which relies on preoperative physical examinations, a CT scan and/or X-rays to determine the desired outcome. This process can be aided by the creation of a 3D model segmented from a preoperative CT scan, allowing a virtual osteotomy planning. The use of 3D models in the preoperative planning phase has been shown to help visualise the anatomy, allowing surgeons to get an initial understanding of the anatomical consequences of an osteotomy in patients with SCFE, resulting in less time spent in the operating room (OR) [10].
Accurate repositioning of the femoral head in patients with SCFE undergoing an Imhäuser osteotomy is challenging, as visualisation and planning using patient-specific 3D models does not provide intraoperative guidance. Correct repositioning requires accurate pre-drilling of the screw holes and positioning of the osteotomy, which can be achieved using a 3D printed patient-specific surgical guide [11, 12]. This guide fits the patient’s bone and assist in drilling and cutting according to plan. The drill holes of the guide correspond to the drill holes of a (patient-specific) plate that is used to affix the osteotomised bones. The use of patient-specific 3D models and a patient-specific cutting guide has been shown to assist the surgeon in determining the intraoperative position and orientation of the osteotomy, resulting in reduce operative time [13]. Lagerburg et al. [14] performed a retrospective study to compare clinical outcomes in patients operated with and without a 3D printed patient-specific surgical guide. A small, but not-significant, improvement in the Southwick angle was demonstrated. We hypothesise that incorrect placement of the surgical guide is one of the reasons for the limited improvement in this clinical parameter. To test this hypothesis, we retrospectively compared the postoperative bone repositioning achieved with the planned position in 3D in patients with SCFE who underwent an intertrochanteric osteotomy using patient-specific surgical guides.
Methods
Patient selection, treatment and imaging
Patients with unilateral SCFE were included in this study if they underwent intertrochanteric osteotomy, based on a 3D planning at OLVG between April 2018 and October 2022. Patients were excluded if a 6-week postoperative follow-up CT scan was not available. Written informed consent was obtained from all patients enrolled in the study. Approval for this study was obtained from the local ethics committee of OLVG.
Patients included in this study underwent a preoperative CT scan to enable virtual surgical planning. Preoperative position planning of the femoral head was based on the surgeon’s experience, using a mirrored version of the contralateral side was used where possible. Virtual models of the affected femur and contralateral femur were created from the preoperative CT scan by delineating of the anatomy of interest (segmentation). The optimal target was adjusted as deemed appropriate by the surgeon for clinical reasons. Virtual planning resulted in a surgical guide for operative drilling of the screw holes and to transfer the osteotomy plane(s) to the patient. A patient-specific plate with screw holes was printed for intraoperative fixation of the bone segments. A further CT scan was performed at least 6 weeks postoperatively to assess bone healing and to quantify the repositioning error. Figure 1 shows the surgical guide and patient-specific plate designed for patient 5 are shown. Figure 2 shows photographs taken during surgery with the surgical guide and plate in place.
Fig. 1.
Left image shows the custom surgical guide and right image shows the custom plate as designed for patient 5
Fig. 2.
Intraoperative use of (a) the custom surgical guide and (b) the custom plate used during surgery
Quantitative evaluation
Pre-operative CT was used for the femoral bone segmentation, preoperative planning and design of the surgical guide and patient-specific plate. Post-operative CT was used for quantitative evaluation of bone alignment and plate positioning. Preoperative and postoperative models of the femur and a postoperative model of the plate were created by segmentation using D2P (Otiqon, 1.03) and 3D Slicer (3D Slicer Community, version 5.0.3) [15]. Custom software was used to quantify the positioning error of the femoral head and of the patient-specific plate and to express positioning parameters in clinically accepted directions by using an anatomical coordinate system [15].
Segmentation. A virtual model of the femur was obtained from the preoperative CT scan by a process called segmentation, using a combination of manual and automatic tools in 3D Slicer [16–18]. Metal artefacts and postoperative callus formation were manually removed using the contralateral side as a reference. The virtual bone models were checked and validated by the operating surgeon.
Coordinate system. The anatomical coordinate system (CS) (Fig. 3) is based on the geometry of the virtual femur and was determined in an automated manner to minimise operator variability. The z-axis was defined in the proximodistal direction by fitting a cylinder through the femoral shaft of the virtual model. The + x-axis pointed towards the trochanter minor and was perpendicular to the z-axis. The + y-axis was perpendicular to the x- and z-axes.
Fig. 3.
Definition of a local coordinate system. A cylinder was fitted through the femoral shaft and the trochanter minor. The midline in the proximodistal direction represents the + z-axis. The + x-axis points toward the trochanter minor. The + y-axis is perpendicular to the + x- and + z-axes. Fitting a blue sphere through the femoral head provided its centre, which served as the centre of rotation in the quantification of malalignment
Position evaluation. The planned position of the proximal femur, including the femoral head, relative to the femoral shaft was considered the target position. Preoperative and postoperative assessment of this relative position was used to quantify (residual) malalignment [19, 20]. Taking into account the aforementioned anatomical coordinate system [19], three translation parameters (x, y, z) and three Euler angles (jx, jy, jz; sequence y, x, z) were extracted to reflect malalignment. In addition, the total translation (
) and total rotation (
) are reported. The centre of the femoral head, fitted by a sphere (Fig. 3), was chosen as the centre of rotation because it was an easily recognisable clinical reference (see Fig. 4).
Fig. 4.
schematic overview of the method showing the different steps taken in this study. Pre and post-operative CT scans were used to create 3D models by segmenting the bones. The 3D bone models of the pre-operative, post-operative and planned models were separated into a proximal (femoral head) and distal (shaft) segment. A coordinate system was created for each patient case. A sphere was fitted to the femoral head to determine its centre, which served as the centre of rotation for the quantification of misalignment. Finally, the (residual) preoperative and postoperative positioning error was calculated using the planned position as reference
Statistics
Rotational and translational differences were compared with a beforehand defined, clinically acceptable difference of 10 degrees and 10 mm. The Shapiro-Wilk normality test was used to determine whether the data sample was drawn from a normally distributed population.
Results
An Imhäuser osteotomy is performed only in SCFE patients with persistent pain and discomfort, or in patients with severely limited ROM (loss of internal rotation). After implementation of 3D planning in 2014, 16 patients underwent an Imhäuser osteotomy, of which five patients also received a post-operative CT scan and were included in this study. In all patients a reduction in translation and rotation deviations was observed postoperatively compared to the preoperative condition for all directions (Fig. 5). Only patient 3 showed an increase in translation deviation in the x direction postoperatively compared to the pre-operative condition. An overcorrection in rotation about the x-axis (ϕx) was seen in patients 1, 4 and 5.
Fig. 5.
Initial preoperative malalignment of the femoral head and residual postoperative malalignment of the femoral head decomposed in each of the anatomical directions for translations along the x-, y-, and z-axes, and rotations about these axes
The positioning error parameters of the femoral head and of the plate, compared to the preoperative plan, are shown in Table 1. In all five cases the total rotational and translational differences between the planned and the postoperative positions were greater than 10 degrees and 10 mm respectively (Fig. 6; Table 1.). The preoperative, planned and postoperative positions of the femoral head for patient 5 are visualized in Fig. 7a. The difference between the planned and postoperative positioning of the plate in the same patient is visualized in Figs. 8 and 7b. Animations for the positioning of the femoral head and of the plate in all patients can be found in the Online Resource (Online Resource 1–16). Figure 9 shows pre- and post-operative X-ray images of patient 5.
Table 1.
Preoperative and postoperative positional errors of the femoral head compared to the preoperative plan, and plate positioning errors. Errors are expressed as residual absolute translation and rotation errors
| Translation parameters, Median (IQR) (mm) | Rotation parameters, Median (IQR) (degrees) | |||||||
|---|---|---|---|---|---|---|---|---|
| x | y | z | Total | ϕx | ϕy | ϕz | Total | |
| Preop error Femoral head |
17.6 (14.7) |
15.1 (11.4) |
3.5 (4.8) |
30.1 (19.6) |
8.5 (18,1) |
31.2 (16.7) |
28.1 (9.6) |
50.9 (9.2) |
|
Postop error Femoral head |
6,8 (6,4) |
8.5 (0.9) |
9,2 (6.8)) |
15,0 (1.2) |
16,3 (12,0) |
5,1 (2.9) |
6,7 (4,7) |
25,0 (10.5) |
|
Postop error Plate positioning |
2,3 (0,8) |
3,1 (1,6) |
2,4 (1,6) |
4,7 (3,0) |
3,6 (1.2) |
2,8 (3.7) |
19,8 (14,8) |
20,3 (13.5) |
Fig. 6.
Total translation (left) and rotation error (right) error of the femoral head, showing the case-by-case preoperative error in each case and the improvement after surgery compared to with the planned position. The planned position is represented by an error value equal to zero
Fig. 7.
(A) Femoral head of patient 5 in pre-operative position (orange), planned position (green), and in the postoperative position (blue). (B) Femoral head including the plate of patient 5 in the planned position (green) and in the postoperative position (blue). The green and blue images are from the virtual models of the pre- and post-operative CT-scans
Fig. 8.
Translation (left) and rotation error (right) of the postoperative plate positioning, representing a deviation from the preoperative planned position
Fig. 9.
Preoperative and postoperative X-ray scans of patient 5. This radiograph shows a unidirectional result of the Imhäuser osteotomy is shown
Discussion
Surgical guides are used to increase the accuracy of the Imhäuser osteotomy procedure and improve the mobility in this young patient population. The current study is the first clinical trial in SCFE patients to evaluate the accuracy of femoral head positioning using 3D-printed surgical guides. In general, an improvement in femoral head positioning is achieved in compared to the preoperative position. However, there is still a difference between the planned and the postoperative position.
Rotational correction of the femoral head around the x- and y-axes has the greatest impact on the clinical outcome. Our results show the largest rotational error of the femoral head around the x-axis (median of 16.3⁰), which corresponds to a clinically important direction.
In patient 3, the total translation error increased postoperatively. This was due to a large overcorrection of 14.4 mm along the x axes n this patient the total rotation error decreased postoperatively compared to preoperatively.
In some of the directions the correction performed was too small compared to the planning and in some directions an overcorrection was performed. Overall, there was a trend of overcorrection in the y translation direction and rotational overcorrection is shown in ϕx and ϕy.
In the five cases of this study the total difference between the planned and the postoperative position of the femoral head was slightly larger than the rotational difference of 10 degrees and larger than the translational difference of 10 mm, which was reported as the clinically acceptable deviation.
The consequence of not achieving the planned position may be a worse clinical outcome with persistent pain and reduced range of motion compared to the ideal position, which is the planned position. However, a previous study in this patient group showed a slightly larger range of motion of the hip after surgery in patients operated with a patient-specific guide compared to patients operated without a surgical guide [14]. Therefore, working with a patient-specific guide is preferred but improvements in the accurate positioning of these guides are needed for an even better clinical outcome.
Differences between postoperative and planned position can be caused by image quality [24] and subsequent errors in segmentation, by guide production, guide fitting [21, 22], and guide placement. Printed guides generally deviate up to 0.2 mm from the CAD file and therefore hardly contribute to surgical error [23–29]. However, sterilisation can have a significant effect on the shape of the guide [30]. Therefore, in this study, polyamide (PA) was chosen as the printing material for the guide and printed by Oceanz, as PA withstands the sterilization process well. Intraoperative placement of the guide is hindered by the visibility of only a small surgical area, the presence of soft tissue remains, and the fact that the does not fit well to the anatomy of the rather circular femur [14], which can easily cause rotation of the guide around the z-axis. The postoperative position of the plate serves as a nice proxy to investigate positioning of the surgical guide [21, 31–33]. In the current study the median rotation of the plate about the z-axis showed was a median of 19.8⁰, confirming the difficulty of positioning the guide on a cylindrical shaft. A possible solution to improve the guides could be a Kirschner wire placed through the surgical guide. For example, in the direction of the lesser trochanter. Intraoperatively, fluoroscopy can be used to check that the K-wire is correctly positioned, ensuring the surgical guide is correctly placed.
Various studies have been performed on 3D printed surgical guides in ex vivo setting. Zakani et al. [34] and Cherkasskiy et al. [35] showed promising results for the use of 3D printed surgical guides for surgery in patients with SCFE. Zakani et al. compared the difference between the planned positions of the drill holes for sub capital osteotomies in patients with SCFE with the postoperative outcome. The wire angulation was found to be significantly more accurate when using the patient-specific drill guide (2.5 ± 1.4 degrees) when compared to the control group (6.3 ± 4.4 degrees) who were operated conventionally. Cherkasskiy et al. [34] evaluated a mock surgery using 3D printed femoral bone was used in their experiments to train the surgeon. The clinical outcomes of the patient were better with less complication, surgery time and fluoroscopy time, however compliance with the planning was not evaluated. The study by Zakani et al. was performed on 3D printed bones and Cherkasskiy et al. [35] evaluated a mock surgery. Therefore, the differences in this study were smaller compared to the current study because there is no effect of other tissue on the bone, the bone is fully visible in the surgical area and there is no restriction in surgical area. In addition, segmentation errors do not play a role because the guide is designed according to the segmentation of the bone, which provides a 100% fit of the surgical guide.
There is no literature on the accuracy of using 3D printed surgical guides in SCFE patients, but there is a large availability of literature on other anatomical areas where 3D printed surgical guides have been shown to be beneficial [22, 36, 37]. The analysis methods used in these studies are comparable to our method. It is therefore likely that the surgical positioning is largely dependent on the fit of the surgical guides, which clearly differs between anatomical regions.
In this study, a coordinate system similar to that used in clinical practice was defined. The centre of the femoral head was chosen as the centre of rotation because it was considered to be the most appealing clinical reference for this purpose and was reproducible in all patients. In this study the reproducibility and ability to compare the results was chosen over the axis used in clinical practice. Therefore, the created axis is slightly different from the axis used in clinical practice, resulting in difficulties in translating the results to clinical practice.
Limitations of this study include. the small sample size of this study. However, the study required making an additional postoperative CT scan to quantify residual positioning errors. By keeping the sample size small we were able to objectify positioning errors while limiting the additional radiation dose to only five children and still report relevant findings. Another limitation of our study is its retrospective nature which limits the clinical information reported.
Conclusion
In conclusion, intertrochanteric osteotomy to correct deformity caused by SCFE is challenging, even when using 3D printed patient-specific guides. Although we achieved reduced femoral head malalignment, a significant residual error remained. It is important to conduct further research to minimise this residual error.
Electronic supplementary material
Below is the link to the electronic supplementary material.
Supplementary Material 1: Femoral head of patient 1 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 2: Rotated movie of the femoral head of patient 1 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 3: Femoral head of patient 2 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 4: Rotated movie of the femoral head of patient 2 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 5: Femoral head of patient 3 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 6: Rotated movie of the femoral head of patient 3 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 7: Femoral head of patient 4 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 8: Rotated movie of the femoral head of patient 4 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 9: Rotated movie of the femoral head of patient 5 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 10: Femoral head including the plate of patient 1 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 11: Rotated movie of the femoral head including the plate of patient 1 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 12: Femoral head including the plate of patient 2 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 13: Rotated movie of the femoral head including the plate of patient 2 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 14: Femoral head including the plate of patient 3 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 15: Rotated movie of the femoral head including the plate of patient 3 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 16: Femoral head including the plate of patient 4 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 17: Rotated movie of the femoral head including the plate of patient 4 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 18: Rotated movie of the femoral head including the plate of patient 5 in the planned position (green) and in the postoperative position (blue)
Author contributions
All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by M. van den Boorn, J.G.G. Dobbe and V. Lagerburg, The first draft of the manuscript was written by M. van den Boorn and J.G.G. Dobbe and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Therefore, M. van den Boorn and J.G.G. Dobbe contributed equally as first authors.
Funding
The authors have no relevant financial or non-financial interests to disclose.
Data availability
All data generated or analysed during this study are included in this published article (and its supplementary information files). Extra information is available from the corresponding author on reasonable request.
Declarations
Ethics approval and consent to participate
This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the local Ethics Committee of OLVG hospital.
Consent for publication
Consent for publication was obtained from all individual participants included in the study.
Informed consent
Informed consent was obtained from all individual participants included in the study.
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.
M. van den Boorn and J. G. G. Dobbe contributed equally to this work.
References
- 1.Witbreuk MM, van Royen BJ, Van Kemenade FJ, Witte BI, van der Sluijs JA. Incidence and gender differences of slipped capital femoral epiphysis in the Netherlands from 1998–2010 combined with a review of the literature on the epidemiology of SCFE. J Child Orthop. 2013;7(2):99–105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Loder RT, Skopelja EN. The epidemiology and demographics of slipped capital femoral epiphysis. ISRN Orthop. 2011;2011:486512. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Pinheiro PC. Nonoperative treatment of slipped capital femoral epiphysis: a scientific study. J Orthop Surg Res. 2011;6:10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Peck DM, Voss LM, Voss TT. Slipped capital femoral epiphysis: diagnosis and management. Am Fam Physician. 2017;95(12):779–84. [PubMed] [Google Scholar]
- 5.Southwick WO. Osteotomy through the lesser trochanter for slipped capital femoral epiphysis. J Bone Joint Surg Am. 1967;49(5):807–35. [PubMed] [Google Scholar]
- 6.Dunn DM. The treatment of adolescent slipping of the Upper femoral epiphysis. J Bone Joint Surg Br. 1964;46:621–9. [PubMed] [Google Scholar]
- 7.Sonnega RJ, van der Sluijs JA, Wainwright AM, Roposch A, Hefti F. Management of slipped capital femoral epiphysis: results of a survey of the members of the European Paediatric Orthopaedic Society. J Child Orthop. 2011;5(6):433–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Imhäuser G. [Imhäuser’s osteotomy in the florid gliding process. Observations on the corresponding work of B.G. Weber]. Z Orthop Ihre Grenzgeb. 1966;102(2):327–9. [PubMed] [Google Scholar]
- 9.Lowndes S, Khanna A, Emery D, Sim J, Maffulli N. Management of unstable slipped upper femoral epiphysis: a meta-analysis. Br Med Bull. 2009;90:133–46. 10.1093/bmb/ldp012. Epub 2009 Apr 17. PMID: 19376800. [DOI] [PubMed] [Google Scholar]
- 10.Cherkasskiy L, Caffrey JP, Szewczyk AF, Cory E, Bomar JD, Farnsworth CL, et al. Patient-specific 3D models aid planning for triplane proximal femoral osteotomy in slipped capital femoral epiphysis. J Child Orthop. 2017;11(2):147–53. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Vlachopoulos L, Schweizer A, Graf M, Nagy L, Fürnstahl P. Three-dimensional postoperative accuracy of extra-articular forearm osteotomies using CT-scan based patient-specific surgical guides. BMC Musculoskelet Disord. 2015;16:336. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Roner S, Vlachopoulos L, Nagy L, Schweizer A, Fürnstahl P. Accuracy and early clinical outcome of 3-Dimensional Planned and guided single-cut osteotomies of Malunited Forearm bones. J Hand Surg Am. 2017;42(12):1031. e1-.e8. [DOI] [PubMed] [Google Scholar]
- 13.Shi J, Lv W, Wang Y, Ma B, Cui W, Liu Z, et al. Three dimensional patient-specific printed cutting guides for closing-wedge distal femoral osteotomy. Int Orthop. 2019;43(3):619–24. [DOI] [PubMed] [Google Scholar]
- 14.Lagerburg V, van den Boorn M, Vorrink S, Amajjar I, Witbreuk M. The clinical value of preoperative 3D planning and 3D surgical guides for Imhauser osteotomy in slipped capital femoral epipysis: a retrospective study. 3D Print Med. 2024;10(1):8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Pieper S, Halle M, Kikinis R, editors. 3D Slicer. 2004 2nd IEEE international symposium on biomedical imaging: nano to macro (IEEE Cat No 04EX821); 2004: IEEE.
- 16.Summerfield JBM. C + + GUI Programming with Qt 4. 2008.
- 17.Ford JM, Kumm TR, Decker SJ. An Analysis of Hounsfield Unit Values and volumetrics from computerized tomography of the proximal femur for sex and age estimation. J Forensic Sci. 2020;65(2):591–6. [DOI] [PubMed] [Google Scholar]
- 18.Beare R, Lehmann G. The watershed transform in ITK-discussion and new developments. 2006.
- 19.Besl PJ. A method for registration of 3-D shapes. IEEE Trans Pattern Anal Mach Intel. 1992;14(2):239–56. [Google Scholar]
- 20.Dobbe JGG, de Roo MGA, Visschers JC, Strackee SD, Streekstra GJ. Evaluation of a Quantitative Method for Carpal Motion Analysis using clinical 3-D and 4-D CT protocols. IEEE Trans Med Imaging. 2019;38(4):1048–57. [DOI] [PubMed] [Google Scholar]
- 21.Caiti G, Dobbe JGG, Strijkers GJ, Strackee SD, Streekstra GJ. Positioning error of custom 3D-printed surgical guides for the radius: influence of fitting location and guide design. Int J Comput Assist Radiol Surg. 2018;13(4):507–18. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Roner S, Carrillo F, Vlachopoulos L, Schweizer A, Nagy L, Fuernstahl P. Improving accuracy of opening-wedge osteotomies of distal radius using a patient-specific ramp-guide technique. BMC Musculoskelet Disord. 2018;19(1):374. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Kanters D, de Vries A, Boon H, Urbach J, Becht A, Kooistra H-A, editors. Quality Assurance in Medical 3D-Printing. World Congress on Medical Physics and Biomedical Engineering 2018; 2019 2019//; Singapore: Springer Nature Singapore.
- 24.Rouze l’Alzit F, Cade R, Naveau A, Babilotte J, Meglioli M, Catros S. Accuracy of commercial 3D printers for the fabrication of surgical guides in dental implantology. J Dent. 2022;117:103909. [DOI] [PubMed] [Google Scholar]
- 25.Msallem B, Sharma N, Cao S, Halbeisen FS, Zeilhofer HF, Thieringer FM. Evaluation of the Dimensional Accuracy of 3D-Printed anatomical Mandibular models using FFF, SLA, SLS, MJ, and BJ Printing Technology. J Clin Med. 2020;9(3). [DOI] [PMC free article] [PubMed]
- 26.Chae MP, Chung RD, Smith JA, Hunter-Smith DJ, Rozen WM. The accuracy of clinical 3D printing in reconstructive surgery: literature review and in vivo validation study. Gland Surg. 2021;10(7):2293–303. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Dorweiler B, Baque PE, Chaban R, Ghazy A, Salem O. Quality Control in 3D Printing: Accuracy analysis of 3D-Printed models of patient-specific anatomy. Mater (Basel). 2021;14(4). [DOI] [PMC free article] [PubMed]
- 28.Emir F, Ayyildiz S. Accuracy evaluation of complete-arch models manufactured by three different 3D printing technologies: a three-dimensional analysis. J Prosthodont Res. 2021;65(3):365–70. [DOI] [PubMed] [Google Scholar]
- 29.Nguyen P, Stanislaus I, McGahon C, Pattabathula K, Bryant S, Pinto N, et al. Quality assurance in 3D-printing: a dimensional accuracy study of patient-specific 3D-printed vascular anatomical models. Front Med Technol. 2023;5:1097850. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Burkhardt F, Handermann L, Rothlauf S, Gintaute A, Vach K, Spies BC, et al. Accuracy of additively manufactured and steam sterilized surgical guides by means of continuous liquid interface production, stereolithography, digital light processing, and fused filament fabrication. J Mech Behav Biomed Mater. 2024;152:106418. [DOI] [PubMed] [Google Scholar]
- 31.Merema BJ, Kraeima J, Ten Duis K, Wendt KW, Warta R, Vos E, et al. The design, production and clinical application of 3D patient-specific implants with drilling guides for acetabular surgery. Injury. 2017;48(11):2540–7. [DOI] [PubMed] [Google Scholar]
- 32.Fiz N, Delgado D, Sanchez X, Sanchez P, Bilbao AM, Oraa J et al. Application of 3D technology and printing for femoral derotation osteotomy: case and technical report. Ann Transl Med. 2017;5(20):400. [DOI] [PMC free article] [PubMed]
- 33.Otsuki B, Takemoto M, Kawanabe K, Awa Y, Akiyama H, Fujibayashi S, et al. Developing a novel custom cutting guide for curved peri-acetabular osteotomy. Int Orthop. 2013;37(6):1033–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Zakani S, Chapman C, Saule A, Cooper A, Mulpuri K, Wilson DR. Computer-assisted subcapital correction osteotomy in slipped capital femoral epiphysis using individualized drill templates. 3D Print Med. 2021;7(1):18. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35.Cherkasskiy L, Caffrey J, Szewczyk A, Cory E, Bomar J, Farnsworth C et al. Patient-specific 3D models aid planning for triplane proximal femoral osteotomy in slipped capital femoral epiphysis. 2017;11(2):147–53. [DOI] [PMC free article] [PubMed]
- 36.Vlachopoulos L, Schweizer A, Graf M, Nagy L, Fürnstahl PJB. Three-dimensional postoperative accuracy of extra-articular forearm osteotomies using CT-scan based patient-specific surgical guides. 2015;16(1):1–8. [DOI] [PMC free article] [PubMed]
- 37.Rosseels W, Herteleer M, Sermon A, Nijs S, Hoekstra H. Corrective osteotomies using patient-specific 3D-printed guides: a critical appraisal. Eur J Trauma Emerg Surg. 2019;45(2):299–307. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Supplementary Material 1: Femoral head of patient 1 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 2: Rotated movie of the femoral head of patient 1 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 3: Femoral head of patient 2 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 4: Rotated movie of the femoral head of patient 2 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 5: Femoral head of patient 3 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 6: Rotated movie of the femoral head of patient 3 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 7: Femoral head of patient 4 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 8: Rotated movie of the femoral head of patient 4 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 9: Rotated movie of the femoral head of patient 5 in pre-operative position (orange), planned position (green), and in the postoperative position (blue)
Supplementary Material 10: Femoral head including the plate of patient 1 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 11: Rotated movie of the femoral head including the plate of patient 1 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 12: Femoral head including the plate of patient 2 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 13: Rotated movie of the femoral head including the plate of patient 2 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 14: Femoral head including the plate of patient 3 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 15: Rotated movie of the femoral head including the plate of patient 3 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 16: Femoral head including the plate of patient 4 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 17: Rotated movie of the femoral head including the plate of patient 4 in the planned position (green) and in the postoperative position (blue)
Supplementary Material 18: Rotated movie of the femoral head including the plate of patient 5 in the planned position (green) and in the postoperative position (blue)
Data Availability Statement
All data generated or analysed during this study are included in this published article (and its supplementary information files). Extra information is available from the corresponding author on reasonable request.