WO2017052011A1

WO2017052011A1 - Method for designing neck of prosthesis for total hip replacement and prosthesis manufactured thereby

Info

Publication number: WO2017052011A1
Application number: PCT/KR2016/002471
Authority: WO
Inventors: 신충수; 노재훈
Original assignee: 서강대학교 산학협력단
Priority date: 2015-09-24
Filing date: 2016-03-11
Publication date: 2017-03-30
Also published as: KR101696842B1

Abstract

A method for designing a neck diameter of a femoral head in a prosthesis comprises the steps of: selecting a parameter for a range of movement and selecting a design variable of a prosthesis; modeling the prosthesis; calculating the range of movement and a stress in the modeled prosthesis; selecting a neck diameter of a femoral head as a finite element, which affects the range of movement and the stress, among design variables; determining an objective function for the neck diameter of the femoral head, using the range of movement and the stress; and determining a neck diameter of the femoral head, which maximizes the range of movement and minimizes the stress, from the objective function.

Description

【Specification】

[Name of invention]

Neck design method of artificial organ for total hip arthroplasty and artificial organ manufactured by the design method

Technical Field

The present invention was made by the task number NRF-2014R1A2A1A11051209 under the auspices of the Ministry of Science, ICT and Future Planning, and the research management specialized agency of the project is Korea Research Foundation,

"Science Research Foundation> Mid-sized Researcher Project> Leap Research Support Project

"Development of real-time user intention detection smart algorithm using bio-signals and development of biomechanics-based lightweight ankle assist device", The research organization is Sogang University, The research period is from November 01, 2014 to September 30, 2017.

The present invention relates to an artificial organ that is rotatably disposed in the acetabulum of the pelvis (pelvi s) in total hip repl acement, more specifically, an artificial organ that can increase the range of motion of the artificial organ. It relates to a neck design method and its artificial engine.

Background Art

The hip joint (coxa) consists of the femur and the acetabular, and is a very large joint in which the spherical femoral head and the cup-shaped acetabular are closely engaged. In addition, it is surrounded by a variety of muscles, the second largest range of motion following the shoulder joint of the human joint, the joint movement is possible even under a load of five times the weight.

On the other hand, the proximal femoral condyle and the acetabular collision of the hip joint due to excessive movement of the joint are called femoroacetabular impingement. pincer type). Referring to FIG. 1 where each type is shown, Cam type deforms in the femoral head and neck, causing collisions. It is mainly seen in the young with high momentum. Prince type deforms in the acetabulum, causing collisions. In either case, if the condition is serious, total hip arthroplasty should be performed, which partially cuts the proximal part of the thigh and implants an artificial organ.

As can be seen in Figure 1, the femoral ball head is a part that is rotatably bound to the acetabular, the neck is connected below the femoral ball head.

The femoral head of the artificial organ used for total arthroplasty can be determined according to the acetabular shape of the patient undergoing total arthroplasty. For necks placed below the femoral head, the larger the diameter, the greater the range of mot ion. Will be reduced. Therefore, the smaller the diameter of the neck, the greater the range of motion, and can overcome the femoral acetabular syndrome with striking the acetabular neck.

However, the problem is that the diameter of the neck can not be reduced. Because reducing the diameter of the neck increases the range of motion of the artificial organ rotating in the acetabular, but the neck is broken by the force applied to the neck.

Therefore, the diameter size of the neck connected to the femoral ball head that is pivotally connected to the acetabular patient of the total hip arthroplasty should be appropriate within the range of motion and the extent of preventing neck breakage.

PCTCW0 03/086244) discloses a feature that controls the surface roughness of the prosthetic stem that can replace the femur, and describes the hip joint or the name or description of the artificial organ that is implanted in the femur and bound to the acetabular bone. See.

[Detailed Description of the Invention]

[Technical problem]

The present invention provides a design method that can calculate the proper diameter of the neck of the artificial engine rotating in the acetabular and the artificial engine produced by the design method.

The present invention provides a design method and an artificial organ that can maximize the range of motion of the artificial organ and at the same time minimize the force applied to the neck. Technical Solution

According to a preferred embodiment of the present invention for achieving the above objects of the present invention, a femoral head rotating in the acetabulum, a stem implanted into the femur, and the femoral head And Design method for determining the neck diameter for the femoral ball head in the artificial organ comprising a neck connecting the stem, Selecting a range of motion (ROM parameter) of the artificial organ rotating in the acetabular, Selecting a design variable of the institution; Modeling the artificial organ based on the selected design parameter of the artificial organ; And calculating a range of mot ion (ROM) of the artificial organ with respect to the motion range parameter in the modeled artificial organ, and calculating a force applied to the artificial organ within the range of motion of the artificial organ. ; Selecting the neck diameter for the femoral head as a finite element influencing the range of motion and the force of design variables of the artificial organ; Determining an objective function of the neck diameter for the femoral ball head using the calculated range of motion of the artificial organ and the maneuver; And determining the neck diameter for the femoral ball head that maximizes the range of motion of the artificial organ among the range of motion and the force from the objective function and minimizes the force.

r 、

¾: ^ 纖讀 £ £ ROM 'x ^'

The objective function is ¾ ^ ROM ', where H is the femoral ball head diameter, N is the neck diameter, STR is the stress, Χ' = Χ / _μχ , = mean value, and η = range of motion parameter. Further, in determining the neck diameter for the femoral ball head, the optimal diameter of the neck providing the maximum range of motion of the artificial organ and the minimum force is the optimal neck diameter (opt imum neck diameter). = 3.783 * head-to-neck diameter rat io + 6.437.

Also, in determining the neck diameter for the femoral head, the optimal range of the neck providing the maximum range of motion of the artificial trachea and the minimum force. The diameter is optimal neck diameter = 0.149 * femoral head diameter +9.944.

Further, in the step of determining the neck diameter for the femoral head, the optimum neck diameter ratio for the femoral head providing the greatest range of motion of the artificial trachea and the minimum stress is 2.2 to 3.0.

In addition, the range of motion parameter is determined by the rotational characteristics of the artificial engine rotating in the acetabular, the range of motion parameters are flexion, extension, internal rotation, external rotation, adduction ( adduction, and abduction.

Specifically, the rotations are all defined as the movement of the femur against the pelvis, and 0 degrees in the anatomical position (see FIG. 2). Flexion and extension are defined as rotations of the left and right axes (also referred to as the medio—lateral axis or transverse axis or left—light axis). Lifting the leg is the flexion, and the leg flips backward. Internal and external rotations are defined as rotations of the longitudinal axis or craniocandal axis, with rotation in the central direction being inward rotation and rotation in the outward direction being outward rotation. Abduction and abduction are defined as rotations of the antero-posterior axis. Abduction is the rotation that approaches the central axis of the body, and rotation that is farther away.

The design parameters of the prosthesis may include any one of the head diameter, the diameter of the neck, the stem-off set, and the neck-stem angle. It may include.

According to another preferred embodiment of the present invention for achieving the above object of the present invention, an artificial organ comprising a femoral head rotating in the acetabular, a stem implanted into the femur, and a neck connecting the femoral head and the stem is Is initiated. The artificial organ maximizes the range of motion of the artificial organ from the objective function of the neck diameter for the femoral head determined using the range of motion of the artificial organ and the stress applied to the artificial organ, and minimizes the force. Having the diameter of the neck determined to be The objective function is,

， Excitation H is the femoral head diameter, N is the neck diameter, STR is the male force, Χ '= Χ / μ: μ-mean value, 1! = Mean range parameter.

Advantageous Effects

According to the neck design method and the artificial engine of the artificial engine according to the present invention, while minimizing the size of the vertical force (pr inc i pal st ress) acting on the stem of the artificial engine while maximizing the range of motion of the artificial engine rotating in the acetabular I can design the neck which I can do. Therefore, the neck fracture which occurs in the total arthroplasty patient implanted with an artificial organ can be prevented beforehand.

[Brief Description of Drawings]

1 is a reference diagram for explaining the femoral acetabular syndrome.

2 is a reference diagram for describing a motion range parameter.

3 is a flow chart for designing an optimal neck.

4 shows the design parameters of the artificial organ.

5 shows the objective function values for neck and femoral heads.

Fig. 6 (a) shows the optimal neck diameter value according to the diameter ratio of the neck to the femoral head and Fig. 6 (b) shows the optimal neck diameter value according to the femoral head diameter. In FIG. 7 the maximum main force values for the neck diameter are indicated at neck and stem axis angles (NSA) of 125, 130 and 135 °.

In FIG. 8, at neck and stem axis angles (NSA) of 125, 130, and 135 °, the ratio of the neck to femoral head and the maximum principal stress values are indicated, with varying neck diameters. In FIG. 9, the neck and stem axial angles (NSA) of 125, 130, and 135 °, the ratio of the neck to the femoral head and the maximum main force values are shown.

10, the ratio of the neck to the femoral head and the maximum main force value are shown. [Form for implementation of invention]

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited or limited by the examples. For reference, in the present description, the same numbers refer to substantially the same elements, and may be described by quoting contents described in other drawings under such a rule, and the contents repeated or deemed apparent to those skilled in the art may be omitted.

Total hip arthroplasty reduces the range of motion (ROM) of the prosthesis (prosthesis), resulting in femoral acetabular stratospheric stones, which can lead to dislocation problems.

At this time, the femoral ball head and neck diameter have a great influence on the range of motion of the artificial organ, but for the large range of motion, reducing the diameter of the neck causes a problem of increasing the main stress on the artificial organ neck. Neck fractures have been reported.

The present invention is to provide an optimized frame of the neck diameter design that can maximize the range of motion while minimizing the force applied to the neck.

1 is a flow chart for designing the optimal neck of the artificial engine according to the present invention. Referring to FIG. 1, first, the motion range parameter is selected, and the design variable of the artificial engine is selected.

The range of motion parameters are determined by the rotational characteristics of the trachea that rotates in the acetabular, specifically, flexion, extension, internal rotat ion, external rotat ion, adduct ion. , And abduct ion.

The range of motion parameters are all defined as the movement of the femur relative to the pelvis (pel vis) and 0 degrees in the anatomical position (see FIG. 2). Flexion and extension are defined as rotations of the left and right axes (referred to as the medio—lateral axis or transverse axis or left—ight axi s). . Internal and external rotations are defined as rotations of the longi tudinal axis or craniocandal axis, with the rotation in the central direction being inward and the rotation in the outward direction being outward. Abduction and abduction are defined as the rotation of the antero-posterior axis, which is the central axis of the body. Closer rotation is adduction, farther rotation is abduction. Here, the motion range parameters are widely used anatomically and are not only used herein.

In addition, the design parameters of the prosthesis include the head di ameter (H), the neck diameter (N), the stem-of fset (S0), and the neck angle (neck). — Stem angleXNSAs), which may refer to FIG. 4.

The 3D CAD (3D CAD) may be used to model artificial organs, and CT image reconstruct ion may be used to model bones (referring to the thighs) where the artificial organs are implanted.

Simulat and calcul at ion can then be performed, specifically calculating the range of motion of the trachea with respect to the range of motion parameters, and the maximum main force applied to the trachea within the range of motion of the trachea. Calculate the maximum pr incipal stress.

For reference, the rotation angle of the artificial organ, that is, the calculation of the motion range, can be calculated for each type of motion range parameter, and the calculation of the motion range is possible because the numerical value of the artificial organ is specifically designed. The calculation of the range of motion has already been carried out in the 2002 Yoshimine study (Yoshimine, F., 2006.The safe-zones for combined cup and neck ant ever s ions that ful fill the essent i al range of mot ion and the i r opt imum combinat ion in total hip replacements.Journal of Biomechani cs 39, 1315-1323.

In addition, the maximum main force applied to the artificial organ may correspond to the vertical force applied to the stem, which can be calculated when the weight of the subject to be simulated and the key set is established, and is widely used for commercial use (ANSYS V14. 5; ANSYS, Inc., Canonsburg, PA, USA) can be used to make calculations without difficulty.

And, among the design variables of the artificial organ can be selected a finite element that affects the movement range and force, the neck diameter for the femoral head can be selected as a finite element. The purpose of neck optimization is to maximize the range of motion while minimizing the force. The femoral head and neck diameter are defined as design variables that affect the force and range of motion. And, using the calculated motion range and power of the artificial organ

The objective function of the neck diameter can be determined.

The objective function is

Where H is the femoral head diameter, N is the neck diameter, STR is the tension (st ress), Χ '= Χ / μ _χ , = mean value, η = type of motion range parameter, Corresponds to the parameter, and its value is 1 to 5. The force term is positive and the range of motion terms is set to negative values, and the terms and range of motion terms are divided by the average of each set and equalized. σ (sigma) means standard deviation. In this embodiment, there are five motion range parameters, where ^η is 1 to 5. In order to obtain the objective function, experimentally, a total of six sets, specifically, femoral stenrof f set are set to 42 隱 and 45 隱, and the neck-shaft (referring to the stem axis) angles 125 and 130 , Including the case of 135 ⁰ . Refer to [Table 1] below for detailed set configuration.

[Table 1]

In the set, the diameter of the femoral ball head is 33 to 51 mm and the neck diameter is 12 to 20 mm, with artificial organs designed for various cases, and the range of motion for various range of motion parameters is calculated. At this time, the main force applied to the neck is limited to less than 150MPa. On the other hand, the optimization of the neck diameter is performed on six data sets to find the optimal point within the proposed constraint. The calculation framework for optimization uses Mat l ab R2014a (Mathworks, Nat ick, MA, USA). The objective function values for the neck and femoral heads are shown in FIG. 5. Looking at Figure 5 shows the smallest function value at 51mm, the largest femoral ball head diameter. In FIG. 5 the NSA is 125 ° and the stem-offset is 42 mm. For every fixed femoral head diameter there is a neck diameter with the smallest objective function value. In general, the objective function value decreases as the diameter of the femoral head increases in each model. On the contrary, it can be understood that the smaller the diameter of the neck, the smaller the objective function value, that is, the magnitude of the force applied to the neck.

6 (a) shows the optimal neck diameter average value according to the ratio of the diameter of the neck to the femoral head. 6 (b) shows the optimal neck diameter average value along the femoral head diameter. The average value of the opt imum point is located on the red linear line, and the optimal neck diameter ranges from 14.4 mm to 17.8 mm, which is the relationship between the optimal neck diameter to the femoral ball and the diameter ratio of the neck. Equation (1) is a linear equation (l inear funct ion) as follows.

Optimal neck diameter (opt imum neck di ameter) = 3.783 * head-to-neck diameter rat io + 6.437-relational expression (1)

In addition, the relational expression (2) regarding the diameter of the femoral ball head and the optimal neck diameter is as follows.

Optimum neck diameter = 0.149 * diameter of femoral ball head +9.994-relation (2)

From the above relation, the range of motion is maximum, and the neck diameter for the femoral head can be determined to minimize the vertical force exerted on the neck, and the optimal neck diameter ratio for the femoral head must be at least 2, preferably Preferably from 2.2 to 3.0. In Figure 7, the maximum main force value for the neck diameter is displayed at the neck and stem axis angles (NSA) of 125, 130, and 135 °, and as the neck diameter increases, the maximum force applied to the neck decreases. This tendency is confirmed by the smaller angles of the neck and stem. The mean value for the maximum main force of the neck diameter is shown in solid lines and the deviation in dotted lines. In FIG. 8, at neck and stem axis angles (NSA) of 125, 130, and 135 °, the ratio of the neck to femoral head and the maximum main force value are shown, with varying neck diameters. In Figure 9, the neck and stem axis angles (NSA) of 125, 130 and 135 °, the ratio of the neck to the femoral head and the maximum main force value are shown, and as the diameter of the femoral head divided by the diameter of the neck increases, It can be seen that the maximum vertical force value becomes small. In other words, when the size of the femoral ball head is determined, the smaller the diameter of the neck, the smaller the maximum force value.

10, the ratio of the neck to the femoral head and the maximum main force value are displayed. As the ratio of the femoral head to the neck increases, the range of motion in the objective function increases.

In FIG. 10, even when the ratio of the femoral head and the neck is the same, it can be seen that the range of motion is large when the angle of the neck and the stem (NSA) is small, and as shown in FIG. 9, the diameter of the neck is small when the NSA is small. As it increases, the maximum force decreases rapidly. Therefore, in patients undergoing total displacement surgery, the diameter of the femoral ball head rotating in the acetabular value corresponds to the determined value. Therefore, the diameter of the neck-stem is reduced in consideration of the range of motion by reducing the diameter of the neck. Can be selected.

In summary, considering the various range of motion parameters, the neck design for the maximum range of motion can be determined by the diameter size of the neck relative to the femoral head, whereby the femoral head can be maximized to maximize the mechanical stability of the trachea. By obtaining an optimized diameter value for the neck, breakage of the neck can be prevented.

As described above, it has been described with reference to the preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

Claims

[Range of request]

[Claim 1]

Said femoral head in an artificial organ comprising a femoral head rotating in an acetabulum, a stem implanted into a femur, and a neck connecting said femoral head and said stem In the design method for determining the neck diameter,

Selecting a ROM parameter of the artificial engine rotating in the acetabular, and selecting a design variable of the artificial engine (des ign var i abl e);

Modeling the artificial organ based on the selected design parameter of the artificial organ; And

Calculating a range of mot ion (ROM) of the artificial organ with respect to the motion range parameter in the modeled artificial organ, and calculating a force applied to the artificial organ within the range of motion of the artificial organ;

Selecting the neck diameter for the femoral head as a finite element influencing the range of motion and the force of design variables of the artificial organ;

Determining an objective function of the neck diameter for the femoral ball head using the calculated range of motion of the artificial organ and the maneuver; And

Determining the neck diameter for the femoral head that maximizes the range of motion of the artificial organ among the range of motion and the force from the objective function and minimizes the force;

Neck design method of artificial engine, characterized in that it comprises a.

[Claim 2]

In the U term, the objective function is

Here, H is the femoral ball head diameter, N is the neck diameter, STR is the stress (stress), Χ '= Χ / μ _χ> = mean value, η-motion range parameter design method of the artificial organ.

[Claim 3]

The method of claim 2

In determining the neck diameter for the femoral head,

The optimal diameter of the neck providing the maximum range of motion of the artificial organ and the minimum force is

Opt imum neck diameter = 3.783 * head-to-neck diameter rat io + 6.437,

Neck design method of artificial engine, characterized in that.

[Claim 4]

The method according to claim 2,

In determining the neck diameter for the femoral head,

The optimal diameter of the neck that provides the maximum range of motion of the artificial organ and the minimum force is

Optimal neck diameter = 0.149 * femoral head diameter +9.944 ，

Neck design method of artificial engine, characterized in that.

[Claim 5]

The method of claim 2,

In determining the neck diameter for the femoral head,

The optimal neck diameter ratio for the femoral ball head providing the maximum range of motion of the artificial trachea and the minimum force is 2.2 to 3.0.

[Claim 6]

According to claim 1,

The range of motion parameter is determined by the rotational characteristics of the artificial engine rotating in the acetabular,

The motion range parameter may include any one of flexion, extension, internal rotation, external rotation, adduct ion, and abduction. Neck design method.

[Claim 7]

In U,

The design parameter of the artificial organ is,

Neck design of an artificial organ comprising any one of the head diameter, the diameter of the neck, the stem-offset, and the neck-stem angle Way.

[Claim 8]

In the artificial organ comprising a femoral head to be metabolized in the acetabular, a stem implanted into the femur, and a neck connecting the femoral head and the stem,

The neck determined to maximize the range of motion of the artificial organ from the objective function of the neck diameter for the femoral head determined using the range of motion of the artificial organ and the force applied to the artificial organ, and to minimize the force Has a diameter of

The objective function is

Where H is the femoral head diameter, N is the neck diameter, STR is the male, Χ '= Χ / _μχ ,

| ^ = Mean value ，

η = artificial engine, characterized in that the movement range parameter.

[Claim 9]

The method of claim 8,

And the optimal diameter of the neck for maximizing the range of motion of the artificial organ and minimizing the force is 3.783 * diameter ratio of neck to femoral head +6.437.

[Claim 10]

The method of claim 8,

And the optimal diameter of the neck for maximizing the range of motion of the artificial organs and for minimizing the stress is 0.149 * diameter of the femoral ball head +9.944.

[Claim 111]

The method of claim 8,

And an optimal neck diameter ratio for the femoral ball head that maximizes the range of motion of the artificial organ and minimizes the force, 2.2 to 3.0.