JPS5846945A - Method and apparatus for diagnosis of dislocation of crotch joint - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a method and device for diagnosing dislocation of a hip joint.

One of the major goals in hip surgery is to restore and maintain lost hip joint afferentity. Many treatments have been tried for this purpose, but none of them are objective or quantitative, relying on past experience or intuition, and their therapeutic effects have been insufficient. .

In particular, surgery for hip dislocation is often performed on children or young children, and if the treatment effect is insufficient as a result of the surgery, it is often difficult for the infant or child to undergo reoperation. A method for diagnosing or surgically dislocating the hip joint has been desired.

It is an object of the present invention to provide a method and a device that can meet these demands and can consistently and objectively diagnose dislocation of a hip joint.

In addition, this invention can be used to treat hip dislocation during surgery! The degree of centripetality, which is a barometer of effectiveness, the state of contact pressure distribution on the contact surface of the hip joint, the magnitude of dislocation force and the state of change in contact pressure distribution when varus osteotomy or pelvic osteotomy is treated. The purpose of the present invention is to provide a method and device for diagnosing dislocation of the hip joint, which enables quantitative understanding of dislocation of the hip joint.

The present invention achieves the above object by performing mechanical analysis of the hip joint using a rigid spring model.

That is, this invention replaces the acetabulum on the pelvis side of the hip joint and the femoral head on the femoral side with element models that do not cause distortion due to stress, and the joint capsular ligament with a dislocation prevention spring. , the area along the contact line between the acetabulum and the femoral head is divided by finite plane elements, and a spring is assumed to resist vertically on the boundary edge of each plane element divided; The shape of the contact line and the load applied to the femoral head are known numbers under the conditions that the friction between the elements along is zero, the displacement of the acetabulum is zero, and the displacement of the head-side plane element is only in two directions within the plane, Calculate the equivalent strain energy stored in the spring from the relative displacement in the two directions using the displacement parameter of the center of gravity of the planar element, and determine the stress applied to each spring from the energy; the maximum tensile force of these springs. Detect the spring that is causing this, and assuming that the spring is cut, calculate the equivalent strain energy stored in the remaining spring from the relative displacement in the two directions, again using the parameters of the center of gravity of the plane element. The above objective is achieved by repeating a calculation loop for calculating the stress applied to the remaining springs from the energy until there are no more springs under tension or a predetermined number of times to calculate the final stress of each spring. It is.

Further, the present invention calculates the attractive force of the spring producing the detected maximum tensile force, and calculates the maximum releasing force that the core spring can receive from this; and then, assuming that the tension spring is cut, Let the maximum release force be the new load applied to the femoral head, and calculate the incremental displacement of the planar element due to this load and the incremental stress applied to each spring other than the cut spring in the same manner as above, and let #stress be the stress from the previous calculation. The stress in each spring is determined by adding the stress in each spring; The above purpose is achieved by searching for until or until it runs out.

Further, the present invention performs calculations for determining the final stress of each spring on a plurality of longitudinal sections of the hip joint, and calculates changes in stress distribution on other sides due to shape modification of the most severe stress distribution section among them through the calculation loop. K thus achieves the above objective.

This invention also includes a digitizer that reads the cross-sectional shape of the hip joint, including the contact line between the pelvic palate and the femoral head; , the abutment on the pelvis side of the hip joint and the femoral head on the femoral side are replaced with element models that do not cause distortion due to stress, and the capsular ligament is replaced with an element model of a dislocation prevention spring. The region along the contact line between the lid and the femoral head is divided into finite plane elements, and a spring is assumed to resist vertically on the boundary edge of each of the divided plane elements; The frictional softness is zero, the displacement of the acetabulum is zero, and the displacement of the cephalic plane element is 2 within the plane.
Conditional only on direction.

Using the displacement parameter of the center of gravity of the plane element,
The equivalent strain energy stored in the spring is calculated from the relative displacement in the direction, and the stress applied to each of the springs is determined from this energy. Assuming that, using the parameters of the center of gravity of the planar element, calculate the equivalent strain energy stored in the remaining spring from the relative displacement in the two directions, and calculate the stress applied to the remaining spring 9 from this energy. Repeat the calculation loop to obtain the final stress of each spring by repeating the calculation loop until there are no more springs under tension or a predetermined number of times, and (1) a display device for displaying the calculation process or result by this calculator; It accomplishes its purpose.

This invention also includes a digitizer that reads the cross-sectional shape of the hip joint, including the contact line between the acetabulum on the pelvic side and the femoral head; In addition, the acetabulum and femoral head of the pelvic extension in the hip joint are rigid bodies that do not cause distortion due to stress, and the capsular ligaments are rigid bodies that do not cause distortion due to stress of the acetabulum and femoral head of the pelvis in the hip joint. Mafc is a joint capsular ligament dislocation prevention spring, in which the area of the acetabulum and the femoral head along the contact line thereof is divided into finite plane elements in a longitudinal section, and on the boundary side of each divided plane element, Assuming a spring that directly resists i&, the friction between the elements along the boundary side is zero, and the die 1
The displacement of 0 is zero, and the displacement of the femoral head side plane is 2 within one plane.
Under the condition of direction only, the equivalent strain energy stored in the spring is calculated from the relative displacement of the two directions using the displacement parameter of the center of gravity of the flat element, and the stress applied to each spring is calculated from the energy. Calculation 4: Detect the spring that produces the maximum tensile force among these springs, and assume that the spring is cut. Again, using the parameters of the center of gravity of the plane element, calculate the remaining bit Me from the relative displacement in two directions. A calculation loop that calculates the equivalent φ energy stored in the spring and calculates the stress applied to the remaining spring from this energy,
The above purpose is achieved by: a calculator that calculates the final stress of each spring by repeating the process until no spring is left under tension or a predetermined number of times; and a display device that displays the calculation process or result on the computer. It is something.

Embodiments of the present invention will be explained below with reference to the drawings.

First, a general mechanical analysis method using the above-mentioned rigid spring model used in the method and apparatus for diagnosing dislocation of a hip joint according to the present invention will be explained.

First, as shown in FIGS. 1 and 2.

As new planar elements, assume two rigid triangular plates 1 and 2, which resist normal force and shear force, and have a spring of 211M.

It is assumed that these rigid triangular plates 1.2Fi stress does not cause intra-element deformation, and that these two triangular plates 1.2Fi stress do not cause any intra-element deformation.
2 and 2 are connected by two types of springs Kd%Ks that resist vertical stress and shear stress, which are continuously distributed on the contact interface 53. The displacement of an arbitrary point P (x, 3F) on the triangular plate is expressed by the displacement of the center of gravity, that is, three components: a parallel displacement component (Uv) and a rotational displacement component (θ). The displacement of 1-tTlvl : UIVn
Jt, the displacement of the center of gravity f i, UIV181 :U
'2. V2 fj2 ''* Toss 7) The following relational expression is obtained.

U-Q・υl' (1
) υ−LUIVI SUivg*' υ1=lUIV1θ1 : U2 V2θ2Jt On the other hand,
Relative displacement vector p / p N after deformation of point P
is given by the following equation.

δ=y-ty (2) Here, the superscript - indicates that it is a component of the local coordinate system taken on the element boundary side.

Now, if R is a coordinate transformation matrix between the global coordinate system and the local coordinate system, the following relationship holds between 0 and U.

UtomiRCU
(3) Here, 135 is the length between the sides 35.

In summary, the above equation t is expressed as follows using the relative displacement vector δFi after the deformation of the point P and the displacement U1 of the center of gravity.

δ=M-RφQ-Ul=B-Ui (B=M-R-Q)
(4) Next, in order to determine the spring constant, a virtual strain component corresponding to the relative displacement component is defined as follows.

Here, K hr ht indicates the length of a perpendicular line drawn from the center of gravity Gt Gy of the triangular plate element to the boundary surface of each element. (See Figure 3) Now, assume that the surface force (stress) per unit area on each element boundary is as follows.

From the above results, the spring constants are determined as follows.

(1) Spring constant in plane strain state Now, assume the following K spring tube.

Therefore, the K spring constant is obtained as follows.

(i) Spring constant in plane stress state can be obtained as follows in exactly the same way as in the case of plane strain.

Note that the spring constant shown here is for convenience only and has no mathematical reason in a strict sense. In order to accurately know the displacement, it is desirable to estimate the spring constant from experimental values and actually measured values.

Now, the relationship between 1%/-h surface force (stress) and relative displacement can be simply written as follows.

σYup, 6 (12)
11'= ('n faJ (stress) δ=δ, J, J
(Relative displacement) From the above, the potential energy stored in the distributed spring system between two elements after deformation is given by the following equation.

■-2'lasδ'Dgds=I, /135 (B5B)
dsUI CU) Therefore, the stiffness matrix for each spring element is obtained from the minimum potential energy theorem 1'.

Table 1 I will explain the case.

That is, as shown in FIG.
As shown in FIG. 5, the rigid bodies 4A and 6A that do not cause distortion due to stress and the joint capsular ligament 7 are replaced with an element model of a dislocation prevention spring 7A, and in the longitudinal section of the element model, the rigid body 4A Assume that the area along the contact line of However, the friction between the elements along the boundary side is zero, that is, the spring constant of the spring is zero, and there are rigid bodies 4A, 6, and roller 8, and the displacement of the rigid body 4A is zero, and the displacement of the rigid body 6A side is zero. 2 in the longitudinal section
direction only, the shape of the contact line and bone 1 [6
Assuming that the load P applied to the plane element is a known value, calculate the equivalent strain energy stored in the spring Kd from the relative displacement in the two directions using the displacement parameter of the center of gravity of the planar element, and calculate the equivalent strain energy stored in the spring Kd from the #energy. Determine the stress: Detect the spring that produces the maximum tensile force among the core springs, assume that the core spring is cut, and again use the parameters of the center of gravity of the planar element to calculate the relative displacement in the two directions. Calculate the equivalent strain energy stored in the remaining 9 other bqK from
The calculation loop for determining the stress applied to the remaining springs K from the energy is repeated until there is no longer a spring under tension or a predetermined number of times to determine the final stress of each spring Kd.

As mentioned above, if the displacement on the rigid body 4 side is zero, then the above (1
4) Since ut s 'It and θt/d in equation (15) are each zero, and M is also zero, the components in the X and Y directions of the load P applied to each plane element K are expressed as K as shown in equation (15). Become.

P yl = Klv u 1 +Ku v Therefore, the value obtained by superimposing Pxl and PYI in each element is:
It becomes equal to the X-direction and Y-direction components of the load P. This is shown as the following equation.

Pxt=(KIp++P-1...)u++(KJ+J'+...)v+PY1=(KI#+-+-)u
l+(#- to K#)Vj(t6) (The superscripts ■, ■... indicate the stiffness of each element.) Here, as mentioned above, l, ni, and Kn are as follows from Table 1. In addition, Pxl and PYI are the X-direction and Y-direction components of the load P, and since both are known quantities, the displacements u 1 and V
1 can be obtained from the formula (凰6).

By substituting the obtained ul and V into (12) 2, the stress of each spring Kd can be obtained.

At the contact surface between the acetabulum 4 and the bone 116, only compressive force exists and there should be no tensile force, so if there is a spring that is generating a tensile force among the springs, the maximum tensile force is generated. After cutting the spring, i.e., assuming that the limb spring part is not in contact with the aceta ft4 and the femoral head 6, the spring stiffness matrix shown in Table 1 is again created under new conditions.

From now on, as before, from equation (16), the displacements u, , vl
Then, the stress of each spring is determined from equation (12).

Among the determined stresses, if there is a tensile force, repeat the above calculation loop until there are no more springs to which the tensile force is applied, or until a predetermined number of times, to obtain the final stress of each spring. .

Repeating the calculation loop up to a predetermined number of times and then aborting it will prevent the program from running out of control when performing this calculation on a computer. , from the X-ray photograph of node 3, use a digitizer 8 to read the cross-sectional shape of the hip joint 3, that is, the X and 7 coordinates of the circumferential shape of each element, to the computer 9; Input the integration point (the contact point of the roller 8 and the dislocation prevention spring 7A) along the contact line of the acetabulum 4 and the femoral head 6 in the plane,
Furthermore, the load P is input from the digitizer 8.

Next, the stiffness matrix for each spring in equation (14) or equation (15) is calculated by the computer 9, and the stress of each spring is determined based on (12) 2 from the created displacement. Determination of the presence or absence of the tensile force...The computer 9 repeats the cutting of the spring and the calculation, and when the calculation converges, the compressive stress tube of each spring is displayed on the graphic display 10 as shown in FIG. 7, for example. indicate.

Here, since the aim of the present invention is to determine the shape of the pressure distribution on the contact surface of the hip joint, the spring constant of each spring may be arbitrary as long as the mutual ratio is kept constant. 9 Assign an appropriate number, such as the number 1, which is convenient for calculations.

The arrow Ftj in FIG. 7 indicates the magnitude of the dislocation force, and if this is above a certain level, it is diagnosed that dislocation has occurred. Further, the range indicated by the symbol N indicates that the spring has been cut.

During the actual surgery, based on the results shown on the graphic display 10, the shape of the contact surfaces of the rigid bodies 4A and 5A is corrected little by little on the display, and the stress of each spring in the corrected cross section is determined in the same way as above. , determine the i-shape that will not cause dislocation. In other words, g! Perform abstract simulation using the raw model.

Therefore, it is no longer necessary to perform a surgery that is similar to the actual eyelid alignment, rather than relying on intuition as in the past, and with the help of a computer and display, it is possible to determine the ideal shape of the hip joint contact surface in advance and perform the surgery. .

Next, a second embodiment of the method for diagnosing dislocation of a hip joint according to the present invention will be described.

This embodiment is similar to the first embodiment in that the equivalent strain energy stored in the spring is calculated from the relative displacement in two directions using the displacement parameter of the center of gravity of the plane element, and the stress applied to each spring is determined from the calculated energy. This example is the same as the first example, but differs from the first example in that the spring that has generated the maximum tensile stress is cut, the release force caused by this cutting is borne by the remaining springs, and the incremental stress of the spring due to this -11 is determined.

In other words, as shown in Fig. 8, a stiffness matrix is created and the incremental displacement (in the first calculation, the previous displacement is specified), and the incremental stress of the spring is calculated based on this incremental cost. This is added to the previous stress (the previous stress is set to zero for the first time) to determine the remaining stress of each spring.

If there is a tensile force among the calculated stresses, detect the spring that produces the maximum tensile force and its value, calculate the maximum releasing force of the tension spring support, and calculate the maximum tensile force as before. A calculation loop is repeated in which the resulting spring is cut and the spring stiffness matrix is calculated using the release force as a new load, until there are no more springs that are under tension.

This embodiment has the advantage that the stress of the spring can be calculated more precisely than the first embodiment, but the calculator for calculation is expensive and the calculation time is slow. 1! ! J! It is longer than the example.

Next, a third embodiment of the method for diagnosing hip joint dislocation according to the present invention shown in FIG. 9 will be described.

In this third embodiment, a plurality of longitudinal sections of the child's hip joint 3 are photographed using a continuous X-ray photographing system, shape data is inputted from each cross-sectional photograph by a digitizer 8, and based on this, the first embodiment The stress distribution of each cross section is determined in the same manner as in the example or the second example, and then the placement stress distribution cross section is determined from among these sections, and the placement stress distribution &I
If the stress distribution in the r-plane is unacceptable, modify the Fi core cross-sectional shape, input the modified shape again via the digitizer, repeat the same calculation loop as in the @l or ifg2 example, and determine the stress distribution when placed. This process is repeated until the stress distribution in the cross section is acceptable, and when the stress distribution becomes acceptable, the changes in stress distribution in other cross sections due to the shape modification are analyzed, and the modified stress distribution including the changes is calculated. If it is acceptable, the calculation is converged; if it is not acceptable, the three-dimensional shape of the company structure model is corrected, input is made again by the digitizer 8, and the calculation loop is repeated.

This process is repeated until the corrected stress distribution is acceptable.

These calculation processes or results are shown on the graphic display 1G as shown in the figure.In the case of this actual case, the corrected shape of the hip joint can be determined three-dimensionally, allowing for more accurate treatment. The advantage is that it can be done.

Since the present invention is configured as described above, it has the excellent effect that the ideal shape of the hip joint can be corrected based on the model, and the therapeutic effect can therefore be dramatically increased. .

As a result of analyzing the cross-sectional shape of the hip joint before and after previous hip dislocation treatment surgery by the present inventors using the method and device of the present invention, all cases were consistent with the diagnostic results obtained by the method and device of the present invention, indicating that the surgery was unsuccessful. I can't figure out the cause either.

[Brief explanation of the drawing]

Figure 1 and Figure 2 are flat diagrams showing a rigid spring model for explaining the principle underlying the hip dislocation diagnosis method according to the present invention, and Figure 3 is a diagram showing the elements used in calculations based on the same principle. A plan view showing numerical values, and Figure 4 is a schematic sectional view showing the shape of the hip joint! Figure 5 is a circular cross-sectional view of the hip joint in Figure 4 replaced with an element model, Figure 6 is a front view of the IIII embodiment of the hip joint dislocation diagnosis method according to the present invention, and Figure 7 is a graph of the calculation results. ), FIG. 10 is a block diagram illustrating the derotation/disassembly Mt of the hip joint according to the present invention. 1.2... Planar element, 3... Hip joint, 4... Acetabular, 4A, 6A. ... rigid body, 5 ... femur, 6 ... femoral head, 7 ... joint capsular ligament, 7A ... dislocation prevention spring, 8
...digitizer, 9...computer, lo...
・Graphic display, kd...spring. Agent Keisuke Matsuyama (#1 or 3) Deaf Figure 6 Figure 7 Perthe5 PRE-OPE Procedure Amendment, Written October 12, 1981 Patent 1i Attorney Shima 1) Haruki Tono 1, of the case Indication 1982 Patent Application No. 145102 2. Title of the invention 3. Relationship with the case of the person making the amendment Patent applicant 5. Date of the amendment order 7. Contents of the amendment (1. Change the title of the invention to 1. Force table small/J method and device fJ. (2) v1v #Shokyu no Han 1111 is revised as shown in the attached sheet. (3) Specification, page 6, line 12, !17Q, line 4, 1 μm
Line 7, line 15, page 13, line 311, line 10, page 2514, line 19, page 26, line 19, page 28, line 29
``Diagnosis'' on the 4th line and 9th line of the page has been changed to ``Rikitafu 1.'' (4) Details - [Surgery 1 on page 7, line 4] is changed to r菰M1. (5) In the specification lJ, 11th member, 1''', line 1 and 134, line 1, ``apparatus'' is changed to ``1 means''. (6) [Diagnosis of IIQ joint 1B2 abutment] in the 1st line of Section 2.0 of the specification is changed to ``Dislocation of the hip joint 1. (7) 1 Reference 1 in the 28th line of the specification , 1 expression”
I'll change it to. Claims: (1) A rigid body that does not cause distortion due to stress on the pelvic side and the femoral head attached to the hip joint; Nogi Shichigel G, °I each W1
In other words, on the vertical plane of the bound tf file (, the &I castle along these contact lines of the 1 profit and femoral head is divided into 6 M finite ψ planes, and the divided Assume a spring with resistance J in the perpendicular i at each plane 'field boundary'; the drag friction along the boundary is zero, the displacement of the zero is zero, and the displacement of p on the head side plane is zero. Under the conditions of only two directions within the plane, the shape of the contact line and the load applied to the femoral head are known numbers, and the displacement parameter of the center of gravity of the plane!!
From the relative displacement in the direction, the strain energy stored in the springs is sieved out, and from this energy, the response J applied to each spring is determined: Detect the spring producing the maximum tensile force on the back of these springs, and Assuming the spring is cut, again,
Said Yogi Hiramuki? Using the parameters of Φ-center

[, Dtit the equivalent strain stored in the remaining spring from the relative displacement in the two directions - L energy, and perform a calculation loop to calculate the stress in the remaining spring from the energy. dislocation of the hip joint, including the process of determining the final stress of each spring by repeating the process up to or until a predetermined time.
LK. (2) Determine the tensile force of the spring that is generating the detected maximum tensile force, and calculate the maximum release of the spring from this: Next, assuming that the tension spring is cut, the maximum release Let be the constant load applied to the femoral head, and the rate i [! ! Determine the incremental displacement of the cable and the incremental stress applied to each spring other than the cut spring in the same manner as above, and add this stress to the stress due to the previous trim to determine the stress in each spring; The calculation loop of cutting the spring producing the maximum tensile force and calculating the incremental stress of other springs due to this cutting is repeated until there are no more springs under tension or a predetermined number of times, and the final stress of each spring is calculated. The hip joint theory (method) according to claim 1, characterized in that . (3) Perform the above 61 steps to determine the final stress of each spring on multiple longitudinal sections of the hip joint, and use the above calculation loop to calculate changes in stress distribution on other sections due to shape modification of the maximum sickle distribution section. Claim No. 110, characterized in that it includes a process of obtaining through the process! , is the method for expressing the dislocation force of the hip joint described in Section 2. (4) A gaugeizer that captures the cross-sectional shape of the hip joint, including the contact line with the acetabular crystal on the pelvic side and the femoral head; based on the cross-sectional shape data obtained by this digitizer and the load data on the femoral head. , l! The acetabulum on the pelvic side and the head on the femoral side in the joint are rigid bodies that do not cause distortion due to stress, and there is also a spring that prevents the capsular ligament from dislodging. Convert each element model to an elementary model, and divide the area of the acetabulum and femoral head along the contact line by using finite planar elements. Each plane! ! On the elemental plane, 11!
Assuming a spring that resists directly, follow the pigeon boundary! l#i
The acetabulum displacement is zero, the displacement of the acetabulum is zero, the change of the 1m element of the head side type (Q is the strip 411' in the 2h direction only in the flat plane, and the displacement parameter of the center of gravity of the flat book is used. Frame the equivalent strain energy stored in the spring from the relative displacement in the two directions, find the stress applied to each spring from the one energy, and detect the spring with the maximum tensile force on the back of these springs. , and assuming that the spring is cut, again the flat al
! Using the parameters of the elementary center of gravity, the equivalent strain energy stored in the remaining spring is calculated from the relative displacement in the two directions, and a calculation loop is performed to calculate the strain response of the remaining spring from this energy. A crotch mgi comprising: a calculator that calculates the final stress of each spring by repeating the process until the applied springs run out or a predetermined number of times; and a display LL that displays the calculation process or result by this calculator.
dislocation force display device. (5) A digitizer that reads the 11m shape including the contact line between the acetabulum on the pelvic side and the femoral head of the hip joint: This digitizer also reads the cross-sectional shape data obtained by this digitizer and the shell data that spans the femoral head. In addition, the acetabulum on the pelvic side and the 1I11i on the femoral side of the hip joint are rigid bodies that do not cause distortion due to stress, and the joint capsular ligament is a prevention spring.
In the m section of the bound model, the area of the acetabulum and the femoral head along the contact line is divided by finite plane elements, and each of the divided Assume a spring with resistance 4 hanging down on one side of the plane catfish jk@S'i, and forward! The love book and dark friction along the boundary is official, the displacement of the acetabular is zero, and the Shun xian side ψth! ! Under the condition that the displacement 11/ of the book is only in the 2h direction within the plane, the phase t4v1 in the 2lJ direction is calculated using the displacement parameter of the center of gravity of the horizontal book.
The equivalent strain energy stored in the springs is sieved out from the stress, and the stress applied to each spring is determined from the tension energy. Assuming that the tension spring is cut, the maximum solution Mt force is the new load applied to the femoral head, and the incremental displacement of the plane surface due to this load and this is determined by the cutting. Determine the incremental stress applied to each spring other than the one above in the same manner as above, add this response to the response calculated from the previous calculation to determine the stress on each spring, and then calculate the maximum tensile force in the same manner as above. The calculation loop of cutting the spring causing the tension and calculating the incremental stress of other springs due to this cutting is repeated until there are no more springs under tension or a predetermined number of times, and the final stress of each spring is calculated. A device for dislocating a hip joint, comprising: a display 11 for displaying the needle line process or result using the calculator;

Claims (5)

[Claims] (1) The acetabulum on the pelvis side of the hip joint and the femoral head on the femoral side are rigid bodies that do not cause distortion due to stress, and the joint capsular ligament is replaced with a JII bulk model model with a spring to prevent dislocation, and the longitudinal section of the element model is In, the acetabulum and the femoral head,
Divide the area along the contact line between the two using finite planar elements, and on the boundary edge of each divided planar element,
- Assuming a spring that resists directly; under the conditions that the friction between the elements along the boundary is zero, the displacement of the acetabulum is zero, and the displacement of the head-side plane element is only in two directions within a few thousand planes; Assuming that the shape of the contact line and the load applied to the femoral head are known, the equivalent strain energy stored in the spring is calculated from the relative displacement in the two directions using the displacement parameter of the center of gravity of the planar element, and the equivalent strain energy stored in the spring is calculated from the bend energy. Determine the stress applied to each spring K; detect the spring producing the maximum tensile force among these springs, assume that the spring is cut, and again use the center of gravity of the plane element (parameter) to calculate the Calculate the equivalent strain energy stored in the remaining spring from the relative displacement in two directions,
A method for diagnosing dislocation of a hip joint, comprising the step of calculating the final stress of each spring by repeating a calculation loop for calculating the stress applied to the springs of the remains of the corpse from the energy until there are no more springs under tension or a predetermined number of times. (2) Determine the tensile force of the spring that is producing the detected maximum tensile force, and calculate from this the maximum releasing force that the spring has; then, assuming that the tension spring is cut, calculate the maximum releasing force. is a new load applied to the femoral head, the incremental displacement of the planar element due to this load and the incremental stress applied to each spring other than the cut spring are determined in the same manner as above, and the skeleton stress is added to the stress calculated previously. Then, the stress in each spring is determined by cutting the spring that produces the maximum tensile force in the same way as above, and the calculation loop is repeated to find the incremental stress in the other springs due to this cutting until no springs are under tensile force. , repeat up to the specified number of times, previous 6C
The method for diagnosing dislocation of a hip joint according to claim 1, characterized in that the final stress of each spring is determined. (3) Calculations to determine the final stress of each spring are performed on multiple longitudinal sections of the hip joint, and changes in stress distribution in other sections due to shape modification of the most severe stress distribution section are determined through the calculation loop. A method for diagnosing dislocation of a hip joint according to claim 1 or 2M. (4) A digitizer that reads the cross-sectional shape of the hip joint, including the contact line between the pelvic palate and the femoral head; Based on the cross-sectional shape data obtained by this digitizer and the load data on the femoral head, the hip joint The acetabulum on the pelvis side and the femoral head on the femoral side are rigid bodies that do not cause distortion due to stress, and the capsular ligament is replaced with an element model of a dislocation prevention spring, and in the longitudinal section of the element model, the acetabulum and the If the region of the femoral head along these contact lines is divided into finite planar elements, and vertical resistance is applied on the boundary edge of each of the divided planar elements, the displacement of the acetabulum becomes zero and the displacement of the femoral head side planar element becomes zero. Under the condition that the displacement is only in two directions in the nucleon plane, the equivalent strain energy stored in the spring is calculated from the relative displacement in the two directions using the displacement parameter of the center of gravity of the planar element, and the Find the stress applied to each spring; detect the spring that produces the maximum tensile force among these springs, assume that the heel spring is cut, and then use the parameters of the center of gravity of the planar element again to calculate the stress in the two directions. The equivalent strain energy stored in the remaining springs is calculated from the relative displacement, and the calculation loop for determining the stress applied to the remaining 9 springs from this energy is repeated until there are no more springs under tension or a predetermined number of times. A dislocation diagnostic device for a hip joint, comprising: a calculator for determining the final stress of a spring; and a display device for displaying the calculation process or result of the computer. (5) a digitizer that reads the cross-sectional shape of the hip joint, including the contact line between the pelvic palate and the femoral head;
Based on the cross-sectional shape data obtained by this digitizer and the load data applied to the femoral head, the acetabulum on the pelvic side of the hip joint and the femoral side are made into rigid bodies that do not cause distortion due to stress, and the capsular ligaments are dislocated. In the longitudinal section of the element model, the area along the contact edge of the acetabulum and the femoral head is divided into finite plane elements, and each of the divided plane elements Assume a vertically resisting spring on the boundary,
The friction between the elements along the boundary side is zero. Under the conditions that the displacement of the acetabulum is zero and the displacement of the cephalic plane element is only twice in the plane, the displacement parameter of the center of gravity of the plane element is used to calculate the relative displacement in the two directions to the spring. Calculate the equivalent strain energy that can be stored, determine the stress applied to each of the springs from this energy, determine the tensile force of the spring that is generating the maximum tensile force among these springs, and calculate the maximum release force that the spring has from this. Then, assuming cutting of the tension spring, the maximum release force is a new load applied to the head, and the incremental displacement of the planar element due to this load and the incremental stress exerted from this on each spring K other than the cut spring are is obtained in the same way as above, and this stress is added to the stress calculated previously, [and the stress of each spring is obtained (
Furthermore, in the same way as above, a calculation loop is performed in which the spring producing the maximum tensile force is cut and the incremental stress of other springs due to this cutting is calculated until there is no longer a spring that is subject to the tensile force, or
A dislocation diagnostic device for a hip joint, comprising: a calculator that calculates the final stress of each spring by repeating the process up to a predetermined number of times; and a display device that displays the calculation process or result of the computer.