CN205411399U - Hip joint prosthesis structure based on strain energy density is optimized - Google Patents

Abstract

The utility model provides a hip joint prosthesis structure based on strain energy density is optimized, it includes false body handle main part, false body handle main part surface is equipped with the plasma coating layer, false body handle main part includes upper segment X and hypomere Y, and upper segment X is 65 with hypomere Y's comparing of length: 79, the error is 3%, is transition region between upper segment X and the hypomere Y, and transition region is level and smooth, has a chamfer, the chamfer is the contained angle of transition face and vertical direction, and the sine value of chamfer is tan0.125, and the error is 3%. The utility model discloses femoral stem prosthesis, handle body length degree is medium, does not have the neck design, and the cross -section is the design of follow -on notch, and proper amount the reduction has increased the area of contact of false body with the bone when cutting the bone. For the zimmerTraper false body, the compact bone substance density regional when the greater trochanter can density respectively reduce 26 -35%, 3.9%, 6 -12% at femoral distal end, the biggest strain energy density on the thighbone with the thighbone mean strain with this false body of 0.862 -0.985 gcm3 at 0.657 -0.780gcm3.

Description

A Hip Prosthesis Structure Based on Strain Energy Density Optimization

technical field

The utility model relates to the field of medical equipment, in particular to a hip joint prosthesis structure based on strain energy density optimization.

Background technique

The implementation of total hip arthroplasty is inseparable from the hip prosthetic stem, and the quality of the prosthetic stem has a decisive impact on the success of total hip arthroplasty. A new prosthesis with a smaller neck-shaft angle and a longer femoral neck was designed, resulting in very good surgical results.

Most of the existing hip femoral stems are standardized designs, which cannot meet the needs of everyone, such as the femoral type with a small neck-shaft angle and a long femoral neck. When using a standardized prosthesis, it will cause Unreasonable osteotomy leads to poor fusion of the prosthesis and bone, resulting in prosthesis loosening.

Bone will undergo bone remodeling after the prosthesis is implanted, and the internal structure of the bone has a great relationship with the bone density, so the material properties of the bone can be expressed by the bone density distribution, and the bone remodeling is the proper distribution of the material density The process of achieving a uniform distribution of strain energy density.

To sum up, a prosthesis with moderate osteotomy, good initial stability and good long-term bone remodeling is suitable for people with apparent bone density at the greater trochanter of 0.657-0.780-0.862g-0.985/cm3. Accounting for about 60% of the total population of our country, this product will have a great market prospect.

Utility model content

The purpose of this utility model is to provide a prosthetic handle with medium length, collarless design, improved notch shape in the cross-section of the handle body, plasma spraying treatment on the surface of the prosthetic handle makes it easier for bone to grow in, appropriately reduces the amount of bone intercepted, and improves Initial prosthesis stability, suitable for femoral stem prosthesis in patients with small neck-shaft angle and long femoral neck.

In order to solve the problems in the prior art, the utility model provides a hip joint prosthesis structure based on strain energy density optimization, which includes a prosthesis handle main body, the surface of the prosthesis handle main body is provided with a plasma spray coating, and the prosthesis handle The main body includes the upper section X and the lower section Y, the ratio of the length of the upper section X to the lower section Y is 65:79, the error is ±3%, the transition area between the upper section X and the lower section Y is smooth, and there is a chamfer, the said The chamfer is the angle between the transition surface and the vertical direction, the sine of the chamfer is tan0.125, and the error is ±3%. The characteristics of the three sections of the main body of the prosthesis are as follows. Section, the BB section is the section in the middle of the transition area of the main body of the prosthesis, and the CC section is the section at the bottom of the main body of the prosthesis. The three sections adopt the same establishment method. The establishment method of the sections: in the Cartesian coordinate system, the three sections are The quasi-ellipse section is composed of 8 line segments, four circular arcs, two large circular arcs and two small circular arcs, and four straight lines. Each straight line is tangent to two adjacent circular arcs. The length of the AA section is The ratio of the axes is 40.32:11, the error is ±3%, the ratio of the radius of the large arc to the small arc is 15:4, and the error is ±3%.

As a further improvement of the present utility model, the vertical length of the transition area is 4 mm, and the error is ±3%.

As a further improvement of the utility model, the ratio of the long and short axes of the BB section is 19.5:8, with an error of ±3%, and the ratio of the radius of the large arc to the small arc is 5:2, with an error of ±3%.

As a further improvement of the utility model, the ratio of the major and minor axes of the CC section is 14.33:6.5, with an error of ±3%, and the ratio of the radius of the large arc to the small arc is 5:3, with an error of ±3%.

The beneficial effects of the utility model are:

The femoral stem prosthesis of the utility model has a medium-length handle body, a collarless design, and an improved notch design in section, which reduces osteotomy appropriately and increases the contact area between the prosthesis and the bone.

The prosthesis of the utility model is double-tapered, and the lower end of the prosthesis handle in the front view is a tapered handle, and it is designed in sections with the proximal end, and the transition of the segmented area is smooth. This design can increase the contact area with the proximal femur , It can also reduce the damage to the medullary cavity, reduce the stress concentration on the femoral stem, and reduce the incidence of femoral stem fracture.

Compared with the Zimmer/Traper prosthesis, when the bone density of the greater trochanter region is 0.657-0.780g/cm3 and 0.862-0.985g/cm3, the prosthesis is at the distal end of the femur, the maximum strain energy density on the femur and the average strain energy of the femur Density was reduced by 26-35%, 3.9%, 6-12%, respectively.

The left view of the utility model is a tapered shape with gradual transition, which can better disperse the force generated by the prosthesis on the femur and make the stress distribution even.

Description of drawings

Fig. 1 is a structural schematic diagram of a hip joint prosthesis based on strain energy density optimization of the utility model;

Fig. 2 is a sectional view of Fig. 1;

Fig. 3A, Fig. 3B, Fig. 3C are AA, BB, CC sectional views of Fig. 2;

Figure 4, Figure 5, and Figure 6 are the strain energy comparison curves of the prosthesis and the traditional ZimmerM/LTraper prosthesis on the femur with different elastic moduli; Figure 4 is the comparison of the proximal femur, Figure 5 is the distal femur, and Figure 6 is the Comparison of the maximum strain energy density on the femur;

Fig. 7 is a schematic diagram of chamfering in the region shown in the B-B section.

detailed description

Below in conjunction with accompanying drawing, the utility model is further described.

The utility model is a proximal anatomical femoral stem prosthesis. The prosthetic stem is of medium length, collarless design, and improved notch-shaped section design. The proximal end of the handle conforms to the anatomical structure of the femur. The surface of the prosthesis is finished by plasma spraying technology. Treatment; the proximal anatomical femoral stem prosthesis adopts a segmented tapered shape from the proximal end to the distal end in the front view, and the transition area has a small chamfer, which can effectively reduce the occurrence of stress concentration and the prosthesis stem. Fracture incidence, the enlarged design of the upper part can increase the contact area between the prosthesis and the femur; from the left view, the transition curve of the prosthesis is very smooth. The femoral stem prosthesis of the utility model can be applied to different patients, and can be selected according to the measurement size of the proximal femur of the patient; it conforms to the anatomical structure of the proximal femur of the human body to the greatest extent, and is suitable for the apparent bone density of the greater trochanter at 0.657 Patients with -0.780 and 0.862-0.985g/cm3 can enable patients to restore the normal movement ability of the human body faster and better, and improve the service life of the prosthesis. The use of this type of femoral stem prosthesis can improve the flexibility of the operation, shorten the operation time, and reduce the pain of the patient.

Referring to shown in Fig. 2, the novel femoral stem prosthesis, the femoral stem handle body (section line part) adopts plasma spraying process.

In Figure 3A, Figure 3B, and Figure 3C, there is a chamfer in the area shown in the B-B section in Figure 2, starting from the top and bottom of the B-B section 2mm, which can keep the upper part of the BB section in contact with the bone in a larger area, and also Can smooth the transition zone while mitigating initial stem subsidence.

The establishment method of the section: the three sections adopt the same establishment method, in the Cartesian coordinate system, this is a quasi-ellipse section, which is composed of 8 line segments and four arcs, see the arcs S1, S2, S3 in Figure 3A , S4, four straight lines, see straight lines L1, L2, L3, L4 in Fig. 3A, each straight line is tangent to two adjacent circular arcs. Point M in the figure is the center point of the quasi-ellipse section, point P is the midpoint of the arc S4, point N is the intersection of the extension lines of straight lines L1 and L2, the length of the line segment MN is the length of the minor axis of the quasi-ellipse section, and the length of PM is The length is the length of the major axis of the quasi-ellipse section. For Fig. 3B and Fig. 3C, the distribution is similar to that of Fig. 3A, that is, there is a change in size.

The ratio of the long and short axes of the AA section is 20.16:5, the ratio of the radius of the large arc (S1, S3) to the small arc (S2, S4) in the figure is 10:1, and the ratio of the long and short axes of the BB section is 39:25 , the ratio of the radius of the large arc to the small arc in the figure is 3:1, the ratio of the long and short axes of the CC section is 14.33:6.5, and the ratio of the radius of the large arc to the small arc in the figure is 5:3, as shown in Figure 2 , the distance from the BB section to the highest point of the AA section is X, the distance from the BB section to the CC section is Y, and the ratio of the length of the upper section X to the lower section Y is 65:79. The advantage of this design: anti-torsion, the four-section arc design can reduce the stress concentration on the medial side of the femur and reduce bone resorption. The sine value of the small chamfer in the figure is tan0.125. The benefits of this design: increase the volume of the upper segment, reduce the initial lower weight.

Referring to Fig. 2, it is shown that the lower end of the prosthesis handle is double-tapered.

Referring to Figure 3A, Figure 3B, and Figure 3C, the cross-sectional shapes at the three main sections are all improved notch sections, and the AA, BB, and CC sections have different sizes, which can be selected according to different patient conditions. Doing so increases the contact area between the prosthesis and the femur.

Referring to Fig. 4, Fig. 5 and Fig. 6 are the comparison curves of the strain energy of the prosthesis and the traditional ZimmerM/LTraper prosthesis on the femur with different elastic modulus. Figure 4 is a comparison of the proximal femur, Figure 5 is a comparison of the distal femur, and Figure 6 is a comparison of the maximum strain energy on the femur. The horizontal axis in the figure is the elastic modulus coefficient on the femur. The elastic modulus of the original femur is 17000Mpa for cortical bone and 3000Mpa for cancellous bone. After multiplying by the coefficient, the elastic modulus of the femur can be changed. Through comparison, it can be seen that the relative For the Zimmer/Traper prosthesis, when the bone density in the greater trochanter region is 0.657-0.780g/cm3 and 0.862-0.985g/cm3, the prosthesis is at the distal end of the femur, the maximum strain energy density on the femur and the average strain energy density of the femur Respectively reduced by 26-35%, 3.9%, 6-12%.

The above content is a further detailed description of the utility model in combination with specific preferred embodiments, and it cannot be assumed that the specific implementation of the utility model is only limited to these descriptions. For a person of ordinary skill in the technical field to which the utility model belongs, without departing from the concept of the utility model, some simple deduction or substitutions can also be made, which should be regarded as belonging to the protection scope of the utility model.

Claims (4)

1. A hip joint prosthesis structure optimized based on strain energy density, characterized in that: it comprises a prosthesis handle main body, the surface of which is provided with a plasma spraying layer, and the prosthesis handle main body includes an upper section X and a lower section Y , the ratio of the length of the upper section X to the lower section Y is 65:79, the error is ±3%, the transition area between the upper section X and the lower section Y is smooth, and there is a chamfer, the chamfer is the transition surface and the vertical The included angle in the vertical direction, the sine of the chamfer is tan0.125, and the error is ±3%. The characteristics of the three sections of the main body of the prosthesis stem are as follows. The AA section is the section at the top of the main body of the prosthesis, and the BB section is the section The section in the middle of the transition area of the handle body, the CC section is the section at the bottom of the prosthetic handle body, the three sections adopt the same establishment method, the establishment method of the sections: in the Cartesian coordinate system, the three sections are quasi-elliptical sections, a total of 8 Composed of four line segments, four arcs, two large arcs and two small arcs, four straight lines, each straight line is tangent to two adjacent arcs, the ratio of the long and short axes of the AA section is 40.32:11 , the error is ±3%, the ratio of the radius of the large arc to the small arc is 15:4, and the error is ±3%. 2 . The hip joint prosthesis structure based on strain energy density optimization according to claim 1 , wherein the vertical length of the transition region is 4 mm, and the error is ±3%. 3. A hip joint prosthesis structure optimized based on strain energy density according to claim 1, characterized in that: the ratio of the major and minor axes of the BB section is 19.5:8, the error is ± 3%, the large arc and the small The ratio of arc radius is 5:2, and the error is ±3%. 4. A hip joint prosthesis structure based on strain energy density optimization according to claim 1, characterized in that: the ratio of the major and minor axes of the CC section is 14.33:6.5, the error is ± 3%, the large arc and the small The ratio of arc radius is 5:3, and the error is ±3%.