The authors have no acknowledgments.

The study was approved by the ethics committee of our institution (reference 2020-277-1). Patients signed the CT scan informed consent.
1. Downloading the CT images
<ol>
	<li>Gain access to a picture archiving and communication system (PACS). 
	NOTE: Each software package has a different way of accessing a PACS, but all of them have a way to download a study in the DICOM format. If there is a question regarding how this is done, ask the system administrator of the center or the radiologists of the center.</li>
	<li>Download the full CT scan in the DICOM format while maintaining patient anonymity.</li>
</ol>
2. Obtaining the 3D biomodel (Supplementary File 1-Figure S1)
<ol>
	<li>Download the software 3D Slicer (see the Table of Materials). Install the program on the computer.</li>
	<li>Import the CT images in the DICOM format.
	<ol>
		<li>Click on the DCM icon on the top-left corner of the screen.</li>
		<li>Click on Import DICOM Files on the left side of the screen, and wait for a window to open that makes it possible to choose the folder where the CT study is saved in the DICOM format.</li>
		<li>Click on &#34;DummyPatName!&#34; on the top right of the screen. If the folder has more than one CT study, click on the series &#34;DummySeriesDesc!&#34; with the most images at the bottom of the screen.</li>
		<li>Click on Load on the lower-right margin.</li>
	</ol>
	</li>
	<li>Create the 3D biomodel.
	<ol>
		<li>Click the menu bar at the top of the screen, and wait for the DICOM to appear.</li>
		<li>In the dropdown menu, choose the Legacy | Editor option. Press ok on the message that appears (Supplementary File 1-Figure S2).</li>
		<li>Wait for a new menu to appear on the left side of the screen. Click on the Threshold Effect icon.</li>
		<li>Move the bar in the lower box until only the bone is painted in the images on the right. In this way, select the value of the Hounsfield units to be included in the model.</li>
		<li>Once the desired paint level is achieved, click on Apply. The selection is marked with the color green (Supplementary File 1-Figure S3).</li>
		<li>Select the option Make Model Effect from the side menu (the same as the previous one). Select Apply (Supplementary File 1-Figure S4).</li>
		<li>In the upper-right window, the 3D model is generated. Click on the golden frame, Center the 3D view on the scene, to center the image in the center of the window (Supplementary File 1-Figure S4).</li>
	</ol>
	</li>
	<li>Save the biomodel (Supplementary File 1-Figure S5).
	<ol>
		<li>Click on Save in the upper-left margin.</li>
		<li>In the box that appears, only select the file &#34;tissue&#34; (Supplementary File 1-Figure S5).</li>
		<li>In the second column, in the dropdown menu, select STL.</li>
		<li>In the third column, in the dropdown menu, choose where to save ithe STL file. Click on Save. This is the file that will be used in the following steps.</li>
	</ol>
	</li>
</ol>
3. Preparation of the biomodel
<ol>
	<li>Download the MeshMixer software (see the Table of Materials). Install the program on the computer.
	<ol>
		<li>Import the STL image by selecting the Import option in the center of the screen (Supplementary File 1-Figure S6).</li>
	</ol>
	</li>
	<li>Select the biomodel.
	<ol>
		<li>Look for the Select option in the menu on the left side. Use any of the following main methods to select.</li>
		<li>Use the Select tool, select the thickness of the brush, and double-click on the femur (Supplementary File 1-Figure S7). If it is not possible to separate only the femur, it means that it has direct contact with other bone structures or soft parts; in that case, select Edit | Generate face Groups from the menu (Supplementary File 1-Figure S7). Use the Angle Threshold option and move the bar until the different structures have a different color, indicating that the pieces have been recognized as separate (Supplementary File 1-Figure S8).
		<ol>
			<li>With the Select tool, hold down the left mouse button while painting the part of the biomodel of interest.</li>
			<li>With the Select tool, click on a point outside the model, and hold down the left mouse button while painting a circle that includes the part that is of interest.</li>
		</ol>
		</li>
		<li>Use the Select tool to select the part of interest. Look for the option Select | Modify | Invert in the side menu, and press Delete&#160;(Supplementary File 1-Figure S9) to delete the unselected parts. At this juncture, the biomodel of the clean femur is obtained (Supplementary File 1-Figure S9).</li>
		<li>Make the model solid (Supplementary File 1-Figure S10).</li>
		<li>Navigate to Edit | Make Solid | Solid Type| Accurate.</li>
		<li>Maximize the Solid Accuracy and Mesh Density values.</li>
	</ol>
	</li>
	<li>Save the biomodel. Select the Export option from the side menu. Select the STL format and the folder to which the biomodel is exported.</li>
</ol>
4. Calculation of the proximal femoral anteversion
<ol>
	<li>Download the 3D Builder software (see the Table of Materials). Install the program on the computer. 
	NOTE: The program can only be downloaded if the operating system of the computer is Windows.</li>
	<li>Click on the Insert icon at the top of the screen (Supplementary File 1-Figure S11). Click on Add to import the biomodel to the scene (Supplementary File 1-Figure S12). 
	NOTE: The left mouse button makes it possible to rotate the object to see it in a 360&#176; view. With the right button, it is possible to scroll along the object. The central wheel of the mouse allows for zooming in.</li>
	<li>Click on Object | Settle to fix the object to the work plane so that it rests on the femoral condyles and the trochanter mayor. 
	NOTE: It is advisable to put the object vertically parallel to the y-axis and perpendicular to the x-axis marked on the working plane (Supplementary File 1-Figure S13).</li>
	<li>Perform the femoral osteotomy.
	<ol>
		<li>Click on Edit | Split from the top menu . When a rectangular cut plane appears, select Keep Both (Supplementary File 1-Figure S14).
		<ol>
			<li>Use the Move Mode button on the bar in the lower margin of the screen to move the cutting plane horizontally and vertically.</li>
		</ol>
		</li>
		<li>Use the Rotate Mode button on the bar in the lower margin of the screen to rotate the plane around the femur (Roll: 90&#176;, Pitch: 0&#176;, Yaw: 0&#176;) (Supplementary File 1-Figure S14).</li>
		<li>Put the cutting plane parallel to the x-axis and perpendicular to the y-axis. Click on Split. In this case, perform the osteotomy above the trochanter minor (intertrochanteric) (Supplementary File 1-Figure S15).</li>
	</ol>
	</li>
	<li>Calculate the femoral anteversion.
	<ol>
		<li>Insert the guides, which help to establish the reference points to measure the femoral anteversion in the image in the 3D environment of the program according to Murphy&#39;s method (Supplementary File 1-Figure S16A,B). To insert the guides, click on Insert | Add, and choose the 3mf Supplementary File 2. 
		NOTE: These guides were designed in-house, and the 3mf file Supplementary File 2 is accessible as a supplementary material provided in this article. The Murphy 3D method was implemented by establishing three measurement points in the same way as in the conventional method11 but in a 3D environment. The usual circumference at the level of the femoral head was replaced by a sphere, and the measurement was established by a circumference at the level of the trochanter minor. As a distal reference, the posterior intercondylar line was taken, as defined in the original Murphy method.</li>
		<li>Select only the proximal part of the femur on the right side of the screen and click on CTRL + X to cut the selection. This is how the femoral diaphysis appears (Supplementary File 1-Figure S17).</li>
		<li>Select the red circular guide and the purple circular guide (doing this means that they will be together) on the right side of the screen. Use the commands in the bottom margin panel to move the guides. 
		NOTE: The red guide represents the rotational axis of the osteotomy, while the violet guide represents the rotational axis of the femur.</li>
		<li>Put the guides in the center of the femoral diaphysis, and use the commands of the inferior margin panel to adjust the size. Ensure that all the edges touch the cortex of the bone (Supplementary File 1-Figure S18). 
		NOTE: When the two guides, the red circumference and the purple circumference, are used for the first time, they are selected together so that they move as a block, as if they were one guide, to measure the FAV, and they are placed in the femoral diaphysis just above the lesser trochanter at the osteotomy line.</li>
		<li>Click on CTRL + V to paste the proximal femur again (Supplementary File 1-Figure S19).</li>
		<li>Select only the sphere on the right side of the screen. Use the commands in the bottom margin panel to move the sphere and place it on top of the femoral head. Adjust the size, including all the edges touching the bone cortex (Supplementary File 1-Figure S20).</li>
		<li>Select the proximal femur on the right side, and cut it (CTRL + X).</li>
		<li>Select only the red plane on the right side of the screen (Supplementary File 1-Figure S21).</li>
		<li>Use the commands in the lower margin panel to move the red plane, and place it so that it passes through the center of the sphere and through the center of the circular guides. 
		NOTE: The grades marked by the panel in the lower margin correspond to the pathological femoral anteversion calculated on the CT using Murphy&#39;s method.</li>
		<li>Press CTRL + V to paste the proximal femur again (Supplementary File 1-Figure S22 A,B) .</li>
	</ol>
	</li>
	<li>Perform the rotational osteotomy of the proximal femur.
	<ol>
		<li>Select the proximal femur + the red circumference (only the red) + the sphere on the right side.</li>
		<li>Make an internal derotational proximal femoral osteotomy of 20&#176; (use the commands on the panel of the lower margin; add 20 on Pitch) (Supplementary File 1-Figure S23).</li>
		<li>Measure the new femoral anteversion (Supplementary File 1-Figure S24). 
		NOTE: The two guides are used again to perform the osteotomy. In this case, only the red guide is selected together with the proximal femur (so that when the proximal femur rotates, the red guide also rotates; step 4.6.1), while the violet guide is not selected (Supplementary File 1-Figure S25). In this way, the violet guide remains in the femoral diaphysis and does not participate in the rotation of the proximal femur.
		<ol>
			<li>Select the proximal femur + the red circumference, and press CTRL + X to cut these two elements.</li>
			<li>Select only the red plane, and place it so that it passes through the center of the sphere and through the center of the purple circular guide. 
			NOTE: A 1:1 relationship between the magnitude of the osteotomy and the correction of the deformity is not achieved because the derotation of the proximal femur does not follow the anatomical axis of the femur.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Perform the adjustment of the rotational osteotomy.
	<ol>
		<li>Select the femoral diaphysis + the red plane. Press CTRL + X to cut (Figure 27). (Supplementary File 1-Figure S25).</li>
		<li>Select the proximal femur + the sphere + the red circumference.</li>
		<li>Move the three elements en bloc so that the center of the red circumference matches the center of the purple circumference&#160;(Supplementary File 1-Figure S26).</li>
		<li>Recalculate the new femoral anteversion with the adjustment made (Supplementary File 1-Figure S27). 
		NOTE: Through this 3D method, it is shown that the rotation axis of the femur and the rotation axis of the osteotomy do not coincide. For this reason, it is necessary to make an adjustment that involves realigning the two guides so that the original femoral axis and the osteotomy axis coincide.</li>
	</ol>
	</li>
</ol>

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</ol>

The authors have no conflicts of interest to disclose.

The most important finding of this study is that 3D technology allows the planning of proximal external derotational femoral osteotomy. This technology can simulate the surgery that is to be performed on a specific patient on the computer. It is a simple, reproducible, and free technique that uses software adaptable to most computers. The only technical problem may be that the 3D builder software works only with the Windows operating system. The major limitation is the learning curve. This protocol is still in the preliminary study phase and can certainly be improved in the future, but it is already an available resource that can help surgeons with decision-making. The technology also heightens the precision of the surgery. In addition, 3D technology can increase surgeons&#39; adherence to this surgical technique. It is also important considering that there are currently no other preoperative planning methods for derotational femoral osteotomy.
The critical procedures during the 3D surgical planning can be summarized in three steps. First, it is important to obtain a good, clean 3D biomodel where only the anatomical part useful for planning is selected. For this, it is necessary to be as accurate as possible during protocol steps 3.3-3.3.2. Second, the intertrochanteric osteotomy must be performed correctly, making sure that the femur is parallel to the x-axis and perpendicular to the y-axis. These axes are already drawn in the work plan of the 3D builder software (protocol steps 4.4.1-4.4.1.3). Third, the femoral anteversion must be calculated correctly in the first measurement and after the osteotomy. For this purpose, the provided guides should be positioned properly. This is done by making sure that the circumferential guides (violet and red) and the sphere are in contact with three points of the cortex of the bone and that the red plane passes exactly through the center of the sphere and the center of the circumferential guides (protocol steps 4.5.1-4.5.9).
The differences observed between group I and group II can be explained as follows. There was no concordance between the femoral rotation axis and the rotation axisof the osteotomy. When both axes coincided in 3D planning, which is called &#34;adjustment&#34;, the relationship between the planned correction and the final correction obtained did coincide. Thus, this 3D technology provides a reliable evaluation of both axes. In this study, there were differences of up to 10&#176; between what was intended to be corrected and what was actually corrected. These degrees of differences could be disastrous for the knee because patellofemoral pressures will significantly worsen13, and the patient&#39;s pain, which is the cause of the consultation, will not be resolved. In addition, 3D technology makes it possible to have the printed femur in the operating room with the osteotomy performed and with the appropriate &#34;adjustment&#34; so that the rotation axis of the femur coincides with the rotation axis of the osteotomy.
The main limitation of this study is the absence of an evaluation ofintra-observer and interobserver variability, which would provide more consistency to the results. In summary, the use of 3D technology for the surgical planning of proximal femoral derotational osteotomy allows the precision of this surgical technique to be improved and provides more certainty to orthopedic surgeons, making this surgery more attractive for them.

Anterior knee pain (AKP) is a common clinical issue among adolescents and young adults. There is a growing body of evidence that increased femoral anteversion (FAV) plays an important role in the genesis of AKP1,2,3,4,5,6,7,8,9,10,11. In addition, this same evidence suggests that a derotational femoral osteotomy is beneficial for these patients, as good clinical results have been reported1,2,3,4,5,6,7,8,9,10,11. However, this type of surgery is not widely used in daily clinical practice among orthopedic surgeons, especially in the cases of adolescents and young active patients with anterior knee pain27, because the many controversial aspects generate uncertainty. For example, it has been observed that sometimes the correction obtained after the osteotomy is not what was previously planned. That is, there is not always a 1:1 ratio between the amount of rotation planned when performing the osteotomy and the amount of FAV corrected. This finding has not been studied to date. Therefore, it is the subject of the present paper. To explain the discrepancy between the magnitude of the rotation performed with the osteotomy and the magnitude of the correction of FAV, it was hypothesized that the axis of rotation of the osteotomy and the axis of rotation of the femur may not coincide.
One of the main problems to be addressed is accurately locating the femoral axis of rotation and the axis of rotation of the osteotomy. The first femoral axis is the femoral axis measured on the CT scan at the time of the patient&#39;s diagnosis, while the second femoral axis is the femoral axis measured after performing the osteotomy. Over the last decade, 3D technology has become increasingly important in preoperative planning, especially in orthopedic surgery and traumatology, for simplifying and optimizing surgical techniques15,16. The development of 3D technology has supported the creation of anatomical biomodels based on 3D imaging tests such as CT, in which customized prosthetic implants can be adapted17,18,19 and osteosynthesis plates can be molded in the case of fractures20,21,22. Additionally, 3D planning has already been used in previous studies to analyze the origin of the deformity in unilateral torsional alterations of the femur14. Currently, there are several software programs that are completely free and adaptable to most computers and 3D printers on the market, making this technology easily accessible to most surgeons in the world. This 3D planning allows for the accurate calculation of the initial axis of rotation of the femur and the axis of rotation of the femur after the intertrochanteric osteotomy has been performed. The main purpose of this study is to demonstrate that the axis of rotation of the femoral intertrochanteric osteotomy and the axis of rotation of the femur do not coincide. This 3D technology makes it possible to visualize this discrepancy between the axes and correct it through an adjustment of the osteotomy. The ultimate goal is to stimulate greater interest from orthopedic surgeons in this type of surgery.
This protocol with a 3D methodology is conducted in four fundamental steps. First, CT images are downloaded, and the 3D biomodel is created from the DICOM (Digital Imaging and Communication in Medicine) files of the CT scan. Higher-quality CT scans allow for better biomodels but mean the patient receives more ionizing radiation. For surgical planning with biomodels, the quality of conventional CT is sufficient. The DICOM image of a CT scan consists of a folder with many different files, with one file for each CT cut made. Each of these files contains not only the CT cut&#39;s graphical information but also the metadata (data associated with the image). To open the image, it is essential to have a folder with all the files of the series (the CT). The biomodel is extracted from the totality of the files.
Second, to obtain the 3D biomodel, it is necessary to download the 3D Slicer computer program, an open-source program with many utilities. Furthermore, this is the most widely used computer software in international 3D laboratories and has the advantage of being completely free of cost and downloadable from its main page. As this software is an X-ray image viewer, the DICOM image must be imported into the program.
Third, the first biomodel obtained with 3D Slicer will not match with the definitive one, because there will be regions such as the CT table or bones and soft parts nearby that are of no interest. The biomodel is &#34;cleaned&#34; almost automatically with the 3D design software, MeshMixer, which can also be downloaded directly from its official website for free. Finally, femoral anteversion is calculated, and the osteotomy is simulated using another free software from the Windows Store, 3D Builder.

<table><tbody><tr><td>3D Builder</td><td>Microsoft Corporation, Washington, USA</td><td></td><td>open-source program; https://apps.microsoft.com/store/detail/3d-builder/9WZDNCRFJ3T6?hl=en-us&amp;amp;gl=us</td></tr><tr><td>3D Slicer</td><td>3D Slicer Harvard Medical School, Massachusetts, USA</td><td></td><td>open-source program; https://download.slicer.org</td></tr><tr><td>MeshMixer&amp;nbsp;</td><td>Autodesk Inc&amp;nbsp;</td><td></td><td>open-source program; https://meshmixer.com/download.html</td></tr></tbody></table>

three-dimensional preoperative virtual planning in derotational proximal femoral osteotomy

Anterior knee pain (AKP) is a common pathology among adolescents and adults. Increased femoral anteversion (FAV) has many clinical manifestations, including AKP. There is growing evidence that increased FAV plays a major role in the genesis of AKP. Furthermore, this same evidence suggests that derotational femoral osteotomy is beneficial for these patients, as good clinical results have been reported. However, this type of surgery is not widely used among orthopedic surgeons.
The first step in attracting orthopedic surgeons to the field of rotational osteotomy is to give them a methodology that simplifies preoperative surgical planning and allows for the previsualization of the results of surgical interventions on computers. To that end, our working group uses 3D technology. The imaging dataset used for surgical planning is based on a CT scan of the patient. This 3D method is open access (OA), meaning it is accessible to any orthopedic surgeon at no economic cost. Furthermore, it not only allows for the quantification of femoral torsion but also for carrying out virtual surgical planning. Interestingly, this 3D technology shows that the magnitude of the intertrochanteric rotational femoral osteotomy does not present a 1:1 relationship with the correction of the deformity. Additionally, this technology allows for the adjustment of the osteotomy so that the relationship between the magnitude of the osteotomy and the correction of the deformity is 1:1. This paper outlines this 3D protocol.

Femoral anteversion can be measured by different methods. Some of them focus on the femoral neck, using the line passing through the center of the neck and one passing through the femoral condyles as references. Others add a third reference point at the lesser trochanter23. Murphy&#39;s method, which is the most reliable in clinical practice because it has the best clinical-radiological relationship, is one such method using a third reference point25,26. In addition, the torsional component of the femur, which varies in the different segments of the bone, contributes to the calculation of the FAV24.
In a preliminary study, the FAV was measured in 10 3D biomodels using Murphy&#39;s method 12. Then, a 10&#176;, 20&#176;, and 30&#176; intertrochanteric rotational femoral osteotomy was simulated on each of the 3D biomodels (Group I). Once the osteotomy was performed, the FAV was remeasured, and it was observed that the rotation axis of the femur did not coincide with the rotation axis of the osteotomy in group I.
Through the 3D guides, one can see that the two axes do not coincide because the red guide does not match the violet guide (3D Builder, Supplementary File 1). The red guide represents the rotational axis of the osteotomy, while the violet guide represents the rotational axis of the femur. For this reason, it is necessary to make an adjustment that involves realigning the two guides so that the rotation axis of the femur and the rotation axis of the osteotomy coincide (3D Builder, steps 4.8.1-4.8.3, Supplementary File 1) (Figure 1).
Therefore, another surgical simulation of the osteotomy was performed, and a reset was needed to match the axis of femoral rotation with the rotation axis of the osteotomy. The resulting FAV was measured again (Group II). Table 1 details the values of the FAV obtained in each group for the three magnitudes of rotational osteotomy (10&#176;, 20&#176;, and 30&#176;). The variable&#34;correction&#34; was defined as the difference between the initial FAV and the FAV measured after the osteotomy. When the adjustment was made so that the femur&#39;s rotation axis and the osteotomy&#39;s rotation axis coincided, the relationship between the planned correctionand the final correction was 1:1 in the three correction magnitudes(10&#176;, 20&#176;, and 30&#176;) (Table 2). The same did not occur in group 1, inwhich the 1:1 ratio was not achieved (Table 2).
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td>Group 1</td>
			<td>Group 2</td>
			<td>P value</td>
		</tr>
		<tr>
			<td>FAV 10&#176;</td>
			<td>22&#176; (&#177;9.1&#186;)</td>
			<td>17.9&#176; (&#177;8.8&#186;)</td>
			<td>&#60;0.001</td>
		</tr>
		<tr>
			<td>FAV 20&#176;</td>
			<td>15.8&#176; (&#177;8.7&#186;)</td>
			<td>7.7&#176; (&#177;9.6&#186;)</td>
			<td>&#60;0.001</td>
		</tr>
		<tr>
			<td>FAV 30&#176;</td>
			<td>8.9&#176; (&#177;8.9&#186;)</td>
			<td>-2.2&#176; (&#177;10.3&#186;)</td>
			<td>&#60;0.001</td>
		</tr>
	</tbody>
</table>
Table 1: FAV comparison between Group 1 and Group 2. The means and SD values are presented.&#160;Abbreviation: FAV = femoral anteversion.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Derotation (correction)</td>
			<td>Group 1</td>
			<td>Group 2</td>
			<td>P value</td>
		</tr>
		<tr>
			<td>10&#176;</td>
			<td>6.9&#176; (&#177;1.4&#186;)</td>
			<td>11.1&#176; (&#177;2.8&#186;)</td>
			<td>&#60;0.001</td>
		</tr>
		<tr>
			<td>20&#176;</td>
			<td>13.1&#176; (&#177;3.2&#186;)</td>
			<td>21.3&#176; (&#177;6.0&#186;)</td>
			<td>&#60;0.001</td>
		</tr>
		<tr>
			<td>30&#176;</td>
			<td>20&#176; (&#177;5.1&#186;)</td>
			<td>31.3&#176; (&#177;8.3&#186;)</td>
			<td>&#60;0.001</td>
		</tr>
	</tbody>
</table>
Table 2: Correction comparison between group 1 and group 2. The means and SD values are presented.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/64774/64774fig01.jpg" /> 
Figure 1: The final outcome: The result of the osteotomy after the adjustment has been applied. There are six panels, which should be read from left to right and from top to bottom.&#160;First panel: femoral anteversion calculated in the CT using Murphy&#39;s method. Second panel: Rotational osteotomy of the proximal femur (internal rotation of 20&#176;). Third panel: New femoral anteversion after the rotational osteotomy of the proximal femur (the final correction does not coincide with the planned correction). Fourth panel: The guides do not match. Fifth panel: Matching the guides. Sixth panel: New femoral anteversion with the adjustment made (the final correction coincides with the planned correction). <a href="https://www.jove.com/files/ftp_upload/64774/64774fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Supplementary File 1: Software instructions. The 3D Slicer software (obtaining and creating the biomodel); the MeshMixer software (making the solid model); the 3D Builder software (importing the biomodel, performing the femoral osteotomy, and calculating the femoral anteversion). <a href="https://www.jove.com/files/ftp_upload/64774/64774_Supp File 1.pdf" target="_blank">Please click here to download this File.</a>
Supplementary File 2: Osteotomy guides. A 3mf file containing the red circular guide, purple circular guide, sphere, and red plane (https://www.dropbox.com/work/JoVE%20Review/File%20requests/64474?preview=Guides+osteotomy+Caterina+Chiappe.3mf).

Watch this Scientific Journal Video about Three-Dimensional Preoperative Virtual Planning in Derotational Proximal Femoral Osteotomy at JoVE.com

Three-Dimensional Preoperative Virtual Planning in Derotational Proximal Femoral Osteotomy

This work presents a detailed surgical planning protocol using 3D technology with free open-source software. This protocol can be used to correctly quantify femoral anteversion and simulate derotational proximal femoral osteotomy for the treatment of anterior knee pain.

Anterior knee pain (AKP) is a common pathology among adolescents and adults. Increased femoral anteversion (FAV) has many clinical manifestations, ...

three-dimensional-preoperative-virtual-planning-derotational-proximal

Universidad Científica del Sur

Research

JoVE Journal

Medicine

996 Views.  Hospital Arnau de Vilanova. This work presents a detailed surgical planning protocol using 3D technology with free open-source software. This protocol can be used to correctly quantify femoral anteversion and simulate derotational proximal femoral osteotomy for the treatment of anterior knee pain.

Video: Three-Dimensional Preoperative Virtual Planning in Derotational Proximal Femoral Osteotomy

Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty

Bone- and soft-tissue sparing short stems are increasingly used in total hip arthroplasty (THA). However, there are a large variety of models of short stems, differing in design and function. Calcar-guided short stems provide an anatomical curvature in the medial calcar region, thus, positioning is done individually alongside the calcar in the "round-the-corner" technique. Depending on the level of the neck's osteotomy, stems can be aligned individually in a large bandwidth of varus- and valgus anatomies. This differs from conventional total hip arthroplasty and potentially includes a severe learning curve. Given that a great variety of caput-collum-diaphyseal (CCD)-angles can be retained, the reconstruction of femoro-acetabular offsets can be achieved precisely. However, particularly extensive varus- and valgus positioning has raised concerns in regard to stability and bone remodeling. The purpose of the present manuscript is to showcase the implantation technique in calcar-guided short-stem THA and to summarize short-term clinical and radiological results.

This protocol describes the round-the-corner technique and the individualized stem-positioning of calcar-guided short stems alongside the medial calcar, depending on the level of the osteotomy. This differs from conventional total hip arthroplasty and includes a learning curve.

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Percutaneous vertebroplasty (PVP) is considered an effective treatment for the back pain caused by osteoporotic vertebral compression fracture. The accuracy of PVP mainly depends on the surgeons&#39; experience and multiple fluoroscopes during a traditional procedure. Puncture related complications were reported all over the world. To make the surgical procedure more precise and decrease the rate of puncture-related complications, our team applied a three-dimensional printing guide template to PVP to modify the traditional procedure. This protocol introduces how to model target vertebrae DICOM imaging data into three-dimensions in the software, how to simulate operation in this 3-D model, and how to use all of the surgical data to reconstruct a patient specific template for application. Using this template, surgeons can identify suitable puncture points accurately to improve the accuracy of the operation. The whole protocol includes: 1) diagnosis of the osteoporotic vertebral compression fracture; 2) acquisition of CT imaging of the target vertebra; 3) simulation of the operation in the software; 4) design and fabrication of the 3-D printing guide template; and 5) application of the template into an operation procedure.

Three-Dimensional Printing Guide Template Assisted Percutaneous Vertebroplasty PVP

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A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible

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3D Planning and Printing of Patient Specific Implants for Reconstruction of Bony Defects

We are in the midst of the 3D era in most aspects of life, and especially in medicine. The surgical discipline is one of the major players in the medical field using the constantly developing 3D planning and printing capabilities. Computer-assisted design (CAD) and computer assisted manufacturing (CAM) are used to describe the 3D planning and manufacturing of the product. The planning and manufacturing of 3D surgical guides and reconstruction implants is performed almost exclusively by engineers. As technology advances and software interfaces become more user-friendly, it raises a question regarding the possibility of transferring the planning and manufacturing to the clinician. The reasons for such a shift are clear: the surgeon has the idea of what he wants to design, and he also knows what is feasible and could be used in the operating room. It allows him to be prepared for any scenario/unexpected results during the operation and allows the surgeon to be creative and express his new ideas using the CAD software. The purpose of this method is to provide clinicians with the ability to create their own surgical guides and reconstruction implants. In this manuscript, a detailed protocol will provide a simple method for segmentation using segmentation software and implant planning using a 3D design software. Following the segmentation and stl file production using segmentation software, the clinician could create a simple patient specific reconstruction plate or a more complex plate with a cradle for bone graft positioning. Surgical guides can be created for accurate resection, hole preparation for proper reconstruction plate positioning or for bone graft harvesting and re-contouring. A case of lower jaw reconstruction following plate fracture and nonunion healing of a trauma sustained injury is detailed.

This protocol describes the use of 3D planning and printing for reconstruction of bony defects. We use segmentation tools to create 3D models followed by 3D design software to create patient specific implants for reconstruction purposes concomitant to ablative surgery or as a second stage.

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Treatment of Facial Deformities using 3D Planning and Printing of Patient-Specific Implants

Technological advancements in surgical planning and patient-specific implants are constantly evolving. One can either adopt the technology to achieve better results, even in the less experienced hand, or continue without it. As technology develops and becomes more user-friendly, we believe it is time to allow the surgeon the option to plan his/her operations and create his/her own patient-specific surgical guides and fixation plates allowing him full control over the process. We present here a protocol for 3D planning of the operation followed by 3D planning and printing of surgical guides and patient-specific fixation implants. During this process we use two commercial computer-assisted design (CAD) software. We also use a fused deposition&#160;modeling printer for the surgical guides and a selective laser sintering printer for the titanium patient-specific fixation implants. The process includes computed tomography (CT) imaging acquisition, 3D segmentation of the skull and facial bones from the CT, 3D planning of the operations, 3D planning of patient-specific fixation implant according to the final position of the bones, 3D planning of surgical guides for performing an accurate osteotomy and preparing the bone for the fixation plates, and 3D printing of the surgical guides and the patient-specific fixation plates. The advantages of the method include full control over the surgery, planned osteotomies and fixation plates, significant reduction in price, reduction in operation duration, superior performance and highly accurate results. Limitations include the need to master the CAD programs.

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Virtual, hybrid three-dimensional (3D) model acquisition is presented in this article, utilizing the sequence of radiographic image segmentation, spatial registration, and free-form surface modeling. Firstly cone-beam computed tomography datasets were reconstructed with a semi-automatic segmentation method. Alveolar bone and teeth are separated into different segments, allowing 3D morphology, and localization of periodontal intrabony defects to be assessed. The severity, extent, and morphology of acute and chronic alveolar ridge defects are validated concerning adjacent teeth. On virtual complex tissue models, positions of dental implants can be planned in 3D. Utilizing spatial registration of IOS and CBCT data and subsequent free-form surface modeling, realistic 3D hybrid models can be acquired, visualizing alveolar bone, teeth, and soft tissues. With the superimposition of IOS and CBCT soft tissue, thickness above the edentulous ridge can be assessed about the underlying bone dimensions; therefore, flap design and surgical flap management can be determined, and occasional complications may be avoided.

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The Use of Mixed Reality in Custom-Made Revision Hip Arthroplasty: A First Case Report

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A complex revision hip arthroplasty was performed using a custom-made implant and mixed reality technology. According to the authors&#39; knowledge, this is the first report of such procedure described in the literature.

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Augmented reality technology was applied to core decompression for osteonecrosis of the femoral head to realize real-time visualization of this surgical procedure. This method can effectively improve the safety and precision of core decompression.

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Author Spotlight: Segmentation and VR for Advanced Neurovascular Interventions

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Clinical Application of Artificial Intelligence Preoperative Planning System Combined with Expert Database Retrieval in Complex Revision Hip Surgery

Accurate preoperative planning in revision hip arthroplasty is crucial for achieving successful outcomes. To enhance the intuitive evaluation of acetabular bone defect severity and leverage previous successful experience in revision hip arthroplasty, this study proposes a novel approach based on expert surgical case database retrieval and is initially implemented in clinical application.&#160;In this study, five patients who required revision hip arthroplasty were preoperatively planned to employ the expert case database surgical planning system.The patient&#39;s imaging data was entered into the system and matched with cases in the expert case database. Based on the expert&#39;s surgical experience, a revision surgery plan was recommended. If no suitable case was found, the model and position of the prosthesis were planned based on patient-specific reconstruction results. A total of five patients were enrolled in this study, four males and one female, with a mean age of 50.6 years. The diagnosis was aseptic prosthesis loosening after hip arthroplasty. The mean operative time was 123.2 min, and the mean intraoperative hemorrhage was 672 mL. No intraoperative complications, such as vascular or nerve injury, were observed. In Case 2, for instance, the application of this innovative planning scheme enabled the surgeon to delineate the revision surgery plan for this patient in the preoperative period, thereby reducing the operative time and intraoperative hemorrhage. Furthermore, patients could be apprised of the outcomes of analogous cases in advance. Leveraging a big data analysis approach through our comprehensive case database enables automated identification of matching expert treatment plans throughout the entire process. This particularly benefits inexperienced orthopedic surgeons by providing accurate guidance on surgical strategies to assist them in selecting appropriate prosthetic sizes and mounting positions. Additionally, the matching results can offer patients visualizations depicting predicted postoperative outcomes.

This study proposes a novel artificial intelligence preoperative planning approach based on expert surgical case database retrieval in revision hip arthroplasty. Additionally, the technique was initially employed in five patients, exhibiting a reduction in operative time and intraoperative hemorrhage.