WO2022124851A1

WO2022124851A1 - Method and apparatus for simulation of total joint arthroplasty for hip joints

Info

Publication number: WO2022124851A1
Application number: PCT/KR2021/018756
Authority: WO
Inventors: 채동식; 강경일; 박성준
Original assignee: 가톨릭관동대학교산학협력단; 한국교통대학교산학협력단
Priority date: 2020-12-11
Filing date: 2021-12-10
Publication date: 2022-06-16
Also published as: KR20220083361A; KR102467242B1

Abstract

An apparatus for simulation of total joint arthroplasty for hip joints, according to the present invention, comprises: an image capturing unit which captures X-ray images of a patient; an image processing unit which stores, as a first layer, image data obtained from the images captured by the image capturing unit, extracts a femur image corresponding to an affected part from the first layer, and divides the femur image into a second layer; an image analysis unit which analyzes the patient's abnormal condition from physical dimensions and angles of a hip joint on the affected side and a normal hip joint by using the image data obtained from the images captured by the image capturing unit, and identifies motion characteristics such as physical dimensions and a range of motion predicted from the condition of the normal hip joint; and a template recommendation unit which provides a doctor in charge of the patient with images according to a plurality of standards of an implant to be inserted into the hip joint on the affected side, and receives a selection.

Description

Total hip arthroplasty simulation method and device

The present invention relates to a method and apparatus for simulating total hip arthroplasty, and more particularly, to a method and apparatus capable of assisting in determining the physical size and position of an implant to be inserted in total hip arthroplasty.

The number of patients suffering joint damage due to disease or accidents is increasing. In some cases, such joint damage can be healed by the body's natural healing ability, but in the case of irreversibility or severe pain due to joint damage, artificial joint replacement surgery is required.

Various artificial joint surgery methods and artificial joint products are being used, but basically, artificial joint replacement surgery precisely cuts both surgically damaged bone and cartilage from both sides of the joint, and then inserts an artificial joint into the bone to replace the joint. It refers to the process of fixing.

Currently, about half of all artificial joint replacement surgeries are hip joint replacement surgery, and most of the rest are knee joints, and it is known that the others are shoulder joints or finger joints.

The hip joint implant shown in FIGS. 1 and 2 may be used for hip replacement surgery. As shown in FIG. 1 , the hip joint implant includes a head 110 , a stem 120 , and a neck 123 , and the acetabular cup 150 is fixed to the pelvic joint bone. The head 110 is accommodated in the shell 155 with a liner interposed therebetween and rotates within a predetermined angle to replace the hip joint.

Meanwhile, in the prior art, after determining the size and location of an implant suitable for the patient by checking the transparent templates shown in FIGS. 3 to 5 on the X-ray photograph of the patient, the total hip arthroplasty is performed accordingly. The size of the cap can be determined using the template of FIG. 3, and the position of the cap of the corresponding size can be determined on the x-ray photograph. Similarly, the size of the stem, the neck, and the head can be determined using the templates of FIGS. 4 and 5, etc. Determine the offset and the rotation center of the joint.

However, in the case of such a conventional method, the precision of the operation may vary depending on the skill of the surgeon. The inconvenience of having to recalculate the size and position of the implant follows.

The present invention is to break away from the method of determining the size and angle of a femur insert while randomly or sequentially overlapping femur templates provided for each two-dimensional (planar) size. Provided are a method and a device according to which data can be selected by providing data on implants of suitable physical specifications.

In addition, the present invention provides a method and apparatus for predicting the result after surgery in order to provide information on an implant to be selected or through a simulation result by an implant of a selected standard and location.

In addition, the present invention provides a simulation method and apparatus capable of quickly taking follow-up measures in response to errors that may occur during a surgical procedure.

The apparatus for simulating total hip arthroplasty according to the present invention includes: a photographing unit that takes an X-ray photograph of a patient; an image processing unit for storing the photo data taken by the photo taking unit as a first layer, extracting a femur image corresponding to the affected part from the first layer, and dividing the image into a second layer; Using the image data captured by the photographing unit, the patient's abnormal state is analyzed from the physical dimensions and angles of the affected hip joint and the normal hip joint, and motions such as physical dimensions and range of motion predicted from the normal hip joint state an image analysis unit for identifying characteristics; and a template recommendation unit selected by providing images according to a plurality of standards of implants to be inserted into the affected hip joint to the doctor in charge of the patient.

It may also include; a simulation unit that calculates joint characteristics and motion characteristics according to physical size and angle by simulating the post-operative state of the affected area according to the specifications of the acetabular cup, head and stem selected through the template recommendation unit.

In addition, the simulation unit, the joint characteristics and movement characteristics of the affected part may be evaluated by comparing the joint characteristics and movement characteristics of the normal side.

In addition, an error response prediction unit that provides data on the type of error that can occur when surgery is performed according to the physical size and location of the implant selected through the template recommendation unit and the standard variation data according to the type of error value; includes; can do.

Also, the standard variation value data may be a data table including a plurality of data pairs of variation values corresponding to error values.

Also, the error type may be at least one of a stem size error, a stem insertion depth error, an acetabular cup inner insertion depth error, an acetabular cup size error, and an acetabular cup insertion angle error.

In addition, the corresponding value according to the type of error may be a variation value of at least one of a receiving groove depth in the head of the implant, an offset of the implant, a stem length of the implant, and a stem size of the implant.

In addition, the template recommendation unit may provide an acetabular cup image of the implant according to a plurality of standards to determine the size of the acetabular cup, the positioning of the acetabular cup, and the rotational center of the acetabular cup on the third layer from the doctor.

Also, the template recommendation unit may mark the rotation center of the acetabular cup determined by the doctor.

In addition, the template recommendation unit provides the head and stem images of the implant according to a plurality of standards, so that the size, position and receiving groove depth of the head and the offset, length and size of the stem can be selected from the doctor on the fourth layer. have.

In addition, the template recommendation unit may be positioned so that the rotational center of the acetabular cup coincides with the rotational center of the head.

According to the present invention, an X-ray photograph suitable for a surgeon who operates by breaking away from the method of determining the size and angle of a femoral implant while randomly or sequentially overlapping the existing two-dimensional (planar) size-specific femur templates By providing data on implants of human size so that they can be selected, it is possible to assist in efficient doctor selection.

In addition, according to the present invention, in order to provide information on the implant to be selected or to predict the postoperative result through the simulation result by the implant of the selected standard and location, comparison of the surgical result can be performed in various ways.

In addition, the present invention can prevent delays during surgery by promptly taking follow-up measures in response to errors that may occur during the surgical procedure.

1 and 2 are photographs showing an example of an implant used in total hip arthroplasty.

3 to 5 are photographs illustrating a template for selecting an acetabular cup and a stem according to an exemplary embodiment.

6 is a block diagram illustrating an apparatus for simulating total hip arthroplasty according to an embodiment.

7 is a schematic diagram for explaining a physical specification of a stem according to an embodiment.

8 is a flowchart illustrating a method for simulating total hip arthroplasty according to an embodiment.

10 to 11 are images illustrating a process of selecting an implant by using each layer.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Unless there is a specific definition or reference, the terms indicating the direction used in this description are based on the state indicated in the drawings. In addition, the same reference numerals refer to the same members throughout each embodiment. On the other hand, each component shown in the drawings may have an exaggerated thickness or dimension for convenience of description, and does not mean that it should actually be configured in a ratio between the corresponding dimensions or components.

A total hip arthroplasty simulation apparatus 200 according to an embodiment will be described with reference to FIGS. 6 and 7 . 6 is a block diagram illustrating an apparatus for simulating total hip arthroplasty according to an embodiment, and FIG. 7 is a schematic diagram for explaining the specifications of an artificial joint implant.

The artificial joint simulation apparatus 200 according to the present embodiment includes a photo capturing unit 210 , an image processing unit 220 , an image analysis unit 230 , a simulation unit 240 , and an error response prediction unit 250 .

The photographic unit 210 obtains basic data by taking an MRI or CT photograph, including an X-ray photograph including a pelvic bone and a femur, for a specific patient. The photo taking unit 210 allows to calculate the length between specific points in the photographed image by using the photographing by placing markers at regular intervals.

The image processing unit 220 stores the photographed photo data as a first layer, extracts an image of the femur therefrom, and divides the image into a separate layer, that is, a second layer.

The image analysis unit 230 calculates the angle of commitment from the physical dimensions and angles of the normal affected hip joint and the contralateral hip joint, such as the femur head, the acetabulum, and the femoral neck, using the image data captured by the photographing unit 210, valgus Analyze the patient's condition, such as high and varus elevation, and identify motion characteristics such as physical dimensions and range of motion predicted from the normal hip joint condition.

The template recommendation unit 240 displays an acetabular cup image on the third layer that can be layered in various sizes to determine the acetabular cup size, positioning, and head depth (center of rotation) so that the doctor can select it. let it be Also, the template recommendation unit 240 may provide a head and stem image for selecting a head and a stem on the fourth layer.

The template recommendation unit 240 can provide data by simply removing from the list the acetabular cup, head, and stem of unapplicable sizes from the data analyzed by the image analysis unit 230 and displaying it, and more actively A method of recommending implant components of an appropriate standard analyzed from the image is also possible. Finally, by applying the images from the presented list to the corresponding layers in turn, the doctor selects the acetabular cup, head, and stem of the appropriate size, and selects the location of the corresponding configuration.

The simulation unit 250 predicts the joint characteristics of the post-operatively affected area through the specifications of the acetabular cup, head, and stem finally selected through the template recommendation unit 240, and uses the predicted post-operative state image. Simulations such as comparison of leg lengths and comparison of conditions with the normal side are performed, and the results are displayed to the doctor. At this time, it is also possible to display the expected problems with respect to the physical movement state. In addition, the simulation unit 250 may perform a simulation for each standard of the acetabular cup, head, and stem to be recommended through the template recommendation unit 240 and present the results together with a recommendation list. That is, the simulation unit 250 may provide a result value to the doctor by simulating the implant before and after determining the size and position for surgery.

When the doctor selects the sizes and positions of the plurality of constituent parts through the template recommendation unit 240 , the simulation results for each case may be displayed together, and the suitability of the selected standards and positions in the simulation may be evaluated.

The error response prediction unit 260 provides a database of errors that may actually occur when surgery is performed according to the selected physical standard and location. It provides data so that doctors can respond quickly without having to leave the operating room and go through separate calculations and tasks. When the types of errors that can occur and corresponding figures according to changes in the corresponding physical specifications are provided in advance, in addition to the implants of the determined physical specifications, the surgery is performed in response to the errors quickly by preparing the implants of the preliminary specifications in advance and performing the operation. can make it go ahead. That is, the type of error, a list of possible standard changes for that type of error, the amount of change in motion characteristics for each list item, or comparison data between the changed motion characteristics and the normal motion characteristics analysis value are presented to promptly respond to the error and perform surgery. make it possible to proceed

For example, when the stem goes into the femur by 1 mm less or more, an error has occurred compared to the planned situation. In the past, there were cases where an ad hoc response was taken, such as leaving the operating room, recalculating it, replacing it with a stem or head of a standard suitable for the calculated items, and resuming the operation in the operating room, or inserting a stem by grinding bones with the eye. In the case of the error response prediction unit 260 according to the present embodiment, in preparation for possible errors, the stem and head specifications according to the follow-up measures are presented in the form of a list for each data in advance so that the error can be quickly responded to.

These surgical errors may occur due to various causes. Although the human body has a three-dimensional shape, it is possible that errors may occur due to limitations in the filming stage. may occur, and errors may occur depending on whether there is a gap between the bone marrow and the cortex. An error may occur during surgery due to such complex causes, and it is difficult to remove the error only from the captured image.

The error response predicting unit 260 provides a data set or data table with a classification for each type of generated error, a changed countermeasure according to the error size, and the corresponding standard of the stem and head, thereby eliminating the need for separate calculation.

For example, if there is a difference between the size determined before surgery and the required stem size when applied during actual surgery, it can be changed simply by inserting a stem of a different size and selecting an appropriate one. The stem size before surgery was determined to be 3 and applied in the actual operation. If there is room for the bone inside the proximal femur where the implant is inserted, increase the size and apply the size lower.

If there is a difference in the depth of stem insertion, change the depth of the receiving groove of the head or change the offset of the stem. When the stem is inserted into the femur, the stem goes in less and sometimes more. At this time, adjust the depth of the receiving groove of the head to match the length of the leg (almost similar to the opposite leg). If the leg is longer than the normal side, select the one with a deep head and insert the stem to expose the neck relatively short. If the leg is shorter than the normal side, select the one with the deep head.

On the other hand, changing the offset of the stem is related to stability. Referring to Figure 7, the stem length (A), the offset (B), the leg adjustment length (C), has the characteristics of the main physical specifications such as the neck length (D). The configuration inserted into the thigh of the stem and the distance to the head correspond to the stem length (A) and the leg adjustment length (C). As described above, when the depth of the receiving groove of the head is changed to adjust the insertion depth, the rotation center is changed and the offset is also changed. In this case, since the position of the femur moves toward the center of the body compared to the normal opposite side of the femur, there may be a problem in stability, so it is necessary to increase the offset. In this case, by adjusting the stem length (A), the offset (B), and the neck length (D), the leg length adjustment and the maintenance of stability can be maximized. can do.

As another example of the error, when a difference in the inner insertion depth of the acetabular cup occurs, the depth of the head receiving groove or the offset of the stem is changed, or the length of the stem is adjusted.

When the acetabular cup is inserted into the acetabulum, if it is inserted deeper into the acetabulum than expected, the center of rotation may move toward the acetabulum and the length of the leg may be shortened. In this case, the length of the legs is adjusted by selecting the shallow depth of the receiving groove of the head so that the neck is exposed relatively long from the head. When the cup is inserted into the acetabulum, it is stable, but when the cup is inserted shallowly, the leg length can be lengthened on the contrary. However, even in this case, since the offset may increase or decrease due to a change in the leg adjustment length C, data can be provided to ensure maximum stability along with the adjustment of the leg length through adjustment of these values.

In general, when a trial artificial joint is inserted, when it is unstable, such as easily dislocated in the hip joint safety test, the method of increasing the offset was used to increase safety. data is provided.

Also, if an error occurs due to the size of the acetabular cup, the size is re-determined in consideration of the degree of exposure or burial of the contact surface of the acetabular cup and the acetabulum and the upper end.

Also, if the angle of the acetabular cup has an error compared to the predetermined angle, more complicated adjustment is required. In general, the angle of the acetabular cup is such that the lower surface of the hemisphere (receiving side of the head) forms an angle of 45 to 50 degrees with respect to the central axis of the body. In this case, not only the leg length is different than expected, but also various deformations of the leg may occur due to the change of the angle of focus. Even in this case, it is possible to evaluate the balance, stability, and movement characteristics after surgery through simulation and provide the appropriate change standard in the form of a data table to the doctor in the form of a data table, etc.

A method of simulating total hip arthroplasty according to an embodiment will be described with reference to FIGS. 8 to 11 . 8 is a flowchart illustrating a method for simulating total hip arthroplasty according to an embodiment, and FIGS. 10 to 11 are images illustrating a process of selecting an implant using each layer.

First, after taking an X-ray picture, it is prepared as a first layer, and the femur is recognized from the X-ray picture and separated into a second layer (S100). At this time, an X-ray picture is taken in an anatomical position, and a marker at a predetermined interval (eg, 10 cm) is placed and taken during imaging, and the size of the implant and calibration can be performed using this.

Next, the acetabular cup size, positioning, and head depth (rotation center) are determined on the third layer (S200). As shown in FIG. 9, images of the acetabular cup are provided on the third layer for various sizes so that the size and position of the acetabular cup can be determined. The appropriate size of the acetabular cup and the position of the rotation center of the artificial joint are determined in consideration of the femoral antevesion on the first layer. At this time, the size is determined by referring to the internal margin, and the rotation center may be marked on the third layer in consideration of the optimal position and bone contact. The determined center of rotation is involved in determining the depth of the stem receiving groove of the head.

Next, as shown in FIG. 10 , a head and a stem are selected on the fourth layer (S300). First, the insertion size, offset, and head depth of the implant head (ball) are determined. Since the head is provided for each depth of the receiving groove for accommodating the stem (especially the neck), the length of the neck exposed from the head is changed when the depth of the receiving groove is changed, and accordingly, the position of the rotation center of the stem is changed.

After that, the stem is selected. Choose a stem size suitable for the proximal femur and equal to the length of the leg. Stem images are available with standard offset or high offset options for all stem sizes. Match the cup's center of rotation to the desired center of rotation to determine the option to restore the appropriate offset.

Next, a simulation is performed with respect to the dimensions and positions of the selected acetabular cup, head, and stem (S400). However, as described above, the simulation can also be performed for a plurality of selections, and even when data of implant components for a plurality of standards and positions are provided to a doctor for selection, data for comparative analysis can be obtained through this. can be provided together. As an example of the simulation performed at this time, as shown in FIG. 11 , a method of calculating the leg length difference by comparing the vertical lengths from the lower ends of both sides of the pelvis to the greater or lesser trochanter of the femur may be considered.

When selection of the final standard and location is completed, a data table is provided for types of errors that may occur and correction values according to error values for each type (S500).

Although the preferred embodiment of the present invention has been described above, the technical spirit of the present invention is not limited to the above-described preferred embodiment, and can be implemented in various ways without departing from the technical spirit of the present invention embodied in the claims. have.

Claims

A photography unit that takes an X-ray picture of the patient;

an image processing unit for storing the photo data taken by the photo taking unit as a first layer, extracting a femur image corresponding to the affected part from the first layer, and dividing the image into a second layer;

Using the image data captured by the photographing unit, the patient's abnormal state is analyzed from the physical dimensions and angles of the affected hip joint and the normal hip joint, and motions such as physical dimensions and range of motion predicted from the normal hip joint state an image analysis unit for identifying characteristics; and

and a template recommendation unit that provides images according to a plurality of standards of implants to be inserted into the affected hip joint to a doctor in charge of the patient, and selects the template recommendation unit.
According to claim 1,

Total hip arthroplasty including; a simulation unit that calculates joint characteristics and motion characteristics according to physical size and angle by simulating the post-operative state of the affected area according to the specifications of the acetabular cup, head and stem selected through the template recommendation unit; simulation device.
3. The method of claim 2,

The simulation unit, a total hip arthroplasty simulation device for evaluating the joint characteristics and motion characteristics of the affected part by comparing them with the joint characteristics and motion characteristics of the normal side.
4. The method of claim 3,

Including a type of error that can occur when surgery is performed according to the physical size and location of the implant selected through the template recommendation unit and an error response prediction unit that provides data on the standard variation value according to the type of error value Total hip arthroplasty simulation device.
5. The method of claim 4,

The standard variation value data is a data table including a plurality of data pairs of variation values corresponding to error values, a total hip arthroplasty simulation apparatus.
5. The method of claim 4,

The error type is at least one of stem size error, stem insertion depth error, acetabular cup inner insertion depth error, acetabular cup size error, and acetabular cup insertion angle error.
7. The method of claim 6,

The corresponding value according to the type of error is a variation value of at least one of a receiving groove depth in the head of the implant, an offset of the implant, a stem length of the implant, and a stem size of the implant.
According to claim 1,

The template recommendation unit provides an image of the acetabular cup of the implant according to a plurality of standards to determine the size of the acetabular cup, the positioning of the acetabular cup, and the rotational center of the acetabular cup on the third layer from the doctor. Replacement surgery simulation device.
9. The method of claim 8,

The template recommendation unit marks the rotation center of the acetabular cup determined by the doctor, a total hip arthroplasty simulation device.
10. The method of claim 9,

The template recommendation unit provides the head and stem images of the implant according to a plurality of standards, and the doctor selects the size, position, and receiving groove depth of the head and the offset, length and size of the stem on the fourth layer. Total arthroplasty simulation device.
11. The method of claim 10,

A total hip arthroplasty simulation apparatus for positioning the template recommendation unit so that the rotational center of the acetabular cup coincides with the rotational center of the head.