A femoral head size measuring hemispherical template kit and method

Abstract

The application discloses a femoral head size measurement hemispherical sample kit and a measurement method, and relates to the technical field of medical devices. The femoral head size measurement hemispherical sample kit comprises a plurality of hollow hemispherical measurement samples with increasing inner diameters. The hollow hemispherical measurement sample comprises a hemispherical shell, the bottom of the hemispherical shell is provided with an opening, and the inside of the hemispherical shell has a cavity. The hemispherical shell is made of a transparent and ductile biocompatible material. The inner diameters of the plurality of hollow hemispherical measurement samples cover a preset femoral head diameter range, and the inner diameter difference between any two adjacent hollow hemispherical measurement samples is a preset step. Based on the technical scheme disclosed by the application, the human operation error is significantly reduced, the bone surface is avoided from being scratched, the operation is simple, the cost is relatively low, the high-precision, high-efficiency and nondestructive measurement of the femoral head size can be realized, the matching error between a prosthesis and the femoral head is reduced, and the matching rate is improved.

Description

Technical Field

[0001] This invention relates to, in particular, to a femoral head size measurement hemispherical template kit and measurement method. Background Technology

[0002] Currently, the clinically used methods for measuring "femoral head size" can be summarized into three types, with the core indicator being femoral head diameter (FHD).

[0003] Firstly, the intraoperative FHD assessment method. During the procedure, the femoral head is completely removed, and cartilage and soft tissue are thoroughly cleared. The vertical diameter and anteroposterior diameter are measured using a vernier caliper with an accuracy of 1 mm, with each measurement repeated at least twice. The average of the maximum values ​​in both directions is the intraoperative measured FHD. This method has limited measurement dimensions, mainly measuring only linear dimensions such as the transverse and longitudinal diameters of the femoral head. It cannot accurately obtain key morphological parameters such as spherical curvature and volume, making it difficult to match the surface design of the prosthesis. Furthermore, this method is susceptible to human error, and for cases of femoral head necrosis, collapse, deformation, or bone defects, the vernier caliper cannot quantify the degree of deformity and is also difficult to accurately measure the effective dimensions of irregular femoral heads.

[0004] Secondly, the imaging FHD assessment method. On a standardized anteroposterior pelvic X-ray, the largest inscribed circle of the femoral head is delineated using the PACS circular tool, and the area S is measured and then converted to the diameter. The operation is simple, but the anastomosis rate is lower than that measured intraoperatively due to the influence of magnification and patient position.

[0005] Thirdly, 3D / navigation measurement. CT 3D reconstruction is used to fit a sphere, or intraoperative AR navigation is used to acquire points and calculate the diameter. The average error is relatively small, but the equipment is expensive and the process is complex, making it difficult for patients in primary hospitals to afford and thus difficult to implement.

[0006] Therefore, developing a femoral head size measurement method that can overcome the above-mentioned shortcomings is of great significance to medical progress. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a femoral head size measurement hemispherical template kit and measurement method, which solves the technical problems of incomplete measurement parameter acquisition, large human error, low concordance rate, cumbersome operation and high cost in the prior art.

[0008] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a femoral head size measurement hemispherical template kit, comprising a plurality of hollow hemispherical measurement templates with increasing inner diameter. The hollow hemispherical measuring template includes a hemispherical shell, the bottom of which has an opening for the femoral head sample to enter, and the interior has a cavity for accommodating the femoral head sample. The hemispherical shell is made of a transparent and flexible biocompatible material, which is configured to undergo elastic deformation under stress and return to its original shape after the stress is removed, and is able to withstand high-temperature sterilization. The inner diameter of the plurality of hollow hemispherical measuring templates covers a preset range of femoral head diameters, and the difference in the inner diameter of any two adjacent hollow hemispherical measuring templates is a preset step size.

[0009] In some embodiments, the biocompatible material is any one of medical-grade thermoplastic polyurethane (TPU), medical-grade silicone, and a rubber-like photosensitive resin with a Shore hardness of A60-90.

[0010] In some embodiments, the opening edge of the hemispherical shell is blunted to form a rounded corner with a radius of 0.2 mm to 0.5 mm to prevent scratching the surface of the femoral head sample during measurement.

[0011] In some embodiments, the preset step size is 1 mm; the plurality of hollow hemispherical measuring templates are divided into a first series and a second series, the first series including measuring templates with an odd number of millimeters in inner diameter, and the second series including measuring templates with an even number of millimeters in inner diameter.

[0012] In some embodiments, the wall thickness of the hemispherical shell is 1.5 mm to 3 mm, and a numerical mark corresponding to its inner diameter is marked on the outer surface or open end face of the hemispherical shell.

[0013] In some embodiments, the opening diameter of the hollow hemispherical measuring template is greater than or equal to its maximum inner diameter, so that the femoral head sample can be fully inserted into the cavity from the opening until its equatorial plane is flush with or nearly flush with the opening end face.

[0014] In some embodiments, the kit further includes an acetabular mold used in conjunction with the plurality of hollow hemispherical measuring templates, the radius of curvature of the acetabular mold being matched with a femoral head prosthesis of the same nominal diameter for use in vacuum adsorption testing after measurement.

[0015] Secondly, the present invention also provides a method for measuring the size of an isolated femoral head based on the hemispherical template kit described in the first aspect, characterized by comprising the following steps: S1. Provide an isolated femoral head sample, the surface of which has been freed of soft tissue and cartilage covering; S2. Based on the visual estimation of the size of the femoral head sample, select a measurement template from the hemispherical template kit whose inner diameter is larger than the estimated size; S3. Push the femoral head sample into the cavity from the opening of the selected measuring template along the long axis direction. S4. Fit judgment: If the femoral head sample has obvious movement gap in the cavity, replace it with a measuring template with a smaller inner diameter and repeat step S3; if the femoral head sample cannot completely enter the cavity or encounters too much resistance during the entry process, replace it with a measuring template with a larger inner diameter and repeat step S3. S5. Determine the measurement results: until a measurement template is found that allows the femoral head sample to fit snugly against the inner wall of the measurement template without significant movement, and the light transmission between the interior and the femoral head sample is uniform through the hemispherical shell. Record the inner diameter value of the measurement template as the diameter data of the femoral head sample.

[0016] In some embodiments, in step S3, the pushing action includes the following steps: after pushing the femoral head sample into the cavity, rotating it 30° to 60° around its long axis, using the slight extensibility of the hemispherical shell to adapt to the minor irregularities on the surface of the femoral head sample, in order to verify the overall fit.

[0017] In some embodiments, the measurement method further includes the following steps: S6. Vacuum Adsorption Verification: Place the femoral head sample with the diameter data determined in step S5 into the inner cavity of the acetabular mold with the same diameter value. Apply axial pressure to expel the air and then remove the external force. Observe whether the femoral head sample is kept in the acetabular mold due to the negative pressure and does not fall off immediately. If the femoral head sample cannot maintain the adsorption state in the acetabular mold or falls off too early, select a measuring template with a smaller inner diameter and repeat step S5.

[0018] Compared with the prior art, the present invention provides a femoral head size measurement hemispherical template kit and measurement method, which constructs a set of hollow hemispherical measurement templates with increasing inner diameter, and is made of a transparent, ductile and high temperature resistant biocompatible material. The physical contact state between the femoral head sample and the inner wall after being placed in the cavity and the uniformity of light transmission are used as the basis for diameter determination.

[0019] This method employs a "face-to-point" circumferential inclusive measurement logic, utilizing the micro-elastic deformation of the material to adaptively fill the micro-roughness and local micro-depressions of the bone surface, thereby accurately locking the effective functional diameter of the femoral head. Simultaneously, the optical properties of the transparent shell enable intuitive visualization of the fit, significantly reducing human error and avoiding scratching the bone surface. It is not only simple to operate and relatively low in cost, but also enables high-precision, high-efficiency, and non-destructive measurement of the femoral head size, thereby reducing the matching error between the prosthesis and the femoral head and improving the fit rate. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of multiple hollow hemispherical measuring templates in one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a single hollow hemispherical measuring template in one embodiment of the present invention; Figure 3 This is a schematic flowchart of an embodiment of the method for measuring the size of an isolated femoral head according to the present invention.

[0021] Explanation of reference numerals in the attached figures: 10, measuring template; 11, hemispherical shell; 111, opening; 112, cavity; 113, rounded corner; 20, biocompatible material. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] To address the aforementioned technical problems, this invention provides a hemispherical template kit and measurement method for measuring femoral head size. While significantly reducing human error and avoiding scratching the bone surface, it is not only simple to operate and relatively low in cost, but also enables high-precision, high-efficiency, and non-destructive measurement of femoral head size, thereby reducing the matching error between the prosthesis and the femoral head and improving the fit rate.

[0024] Please see Figure 1-2 This invention provides a femoral head size measurement hemispherical template kit, which includes multiple hollow hemispherical measurement templates 10. The inner diameter of the multiple hollow hemispherical measurement templates 10 is set in an increasing order, and their inner diameter can cover the diameter range of common femoral heads in clinical practice.

[0025] In this embodiment, taking any one of the hollow hemispherical measuring templates 10 as an example, the hollow hemispherical measuring template 10 includes a hemispherical shell 11. The interior of the hemispherical shell 11 has a hemispherical cavity for accommodating the femoral head sample, and its bottom is provided with an opening 111 for the femoral head sample to enter. The opening 111 can serve as the only channel for the femoral head sample to enter and exit the cavity 112.

[0026] In one embodiment, such as Figure 1As shown, the hemispherical shell 11 can be made of a transparent and elastic biocompatible material 20. This biocompatible material 20 is configured to undergo elastic deformation under stress and return to its original shape after the stress is removed, and is capable of withstanding high-temperature sterilization. Specifically, the biocompatible material 20 can be any one of medical-grade thermoplastic polyurethane (TPU), medical-grade silicone, and a rubber-like photosensitive resin with a Shore hardness of A60-90.

[0027] For example, in one typical application scenario, the biocompatible material 20 can be made of medical-grade thermoplastic polyurethane (TPU), with a Shore hardness that can be controlled at around A75. This material has high light transmittance and no haze, facilitating clear observation of the internal structure; simultaneously, it possesses micron-level elastic deformation capability, capable of accommodating tiny protrusions on the bone surface, and can quickly recover after the external force is removed; furthermore, the material can withstand high-temperature, high-pressure steam sterilization at 134 degrees Celsius, meeting the requirements for repeated use in operating rooms.

[0028] When actually forming the hollow hemispherical measuring template 10, it can be formed by 3D printing or other forming methods, and there is no specific limitation on this.

[0029] In one embodiment, such as Figure 2 As shown, the edge of the opening 111 at the bottom of the hemispherical shell 11 can be blunted to form a rounded corner 113 with a radius of 0.2 mm to 0.5 mm. For example, a rounded corner 113 of 0.2 mm or 0.3 mm can be set to prevent scratching the surface of the femoral head sample during the measurement process.

[0030] For example, in one typical application scenario, the edge of the opening 111 at the bottom of the hemispherical shell 11 can be processed into a rounded corner 113 with a radius of 0.3 mm to avoid scratching the bone surface and the operator's hands.

[0031] It should be noted that, in this embodiment, the diameter of the opening 111 at the bottom of the hemispherical shell 11 should be larger than the maximum inner diameter of the corresponding measuring sample 10 (for example, it can be 0.1-0.2 mm larger). In this way, the femoral head sample can be completely inserted into the cavity from the opening 111 until its equatorial plane is flush with or nearly flush with the end face of the opening 111, so as to achieve accurate measurement.

[0032] Meanwhile, the wall thickness of the hemispherical shell 11 can be flexibly set as needed, for example, it can be set to 1.5mm to 3mm, without specific limitation. In addition, numerical markings corresponding to its inner diameter can be marked on the outer surface of the hemispherical shell 11 or the end face of the bottom opening 111.

[0033] In one embodiment, the inner diameter of the plurality of hollow hemispherical measuring templates 10 preferably covers a preset range of femoral head diameters, and the difference in inner diameter between any two adjacent hollow hemispherical measuring templates 10 can be set as a preset step size.

[0034] Based on this, the inner diameter range of multiple hollow hemispherical measuring templates 10 can be determined according to the common femoral head diameter range in clinical practice. For example, in one typical application scenario, the inner diameter of multiple hollow hemispherical measuring templates 10 can cover commonly used size specifications of 39-55mm.

[0035] Meanwhile, the preset step size can be flexibly set as needed. For example, in a typical application scenario, the preset step size can be set to 1mm. In this case, the inner diameter of the multiple hollow hemispherical measuring templates 10 increases sequentially, and the inner diameter of any two adjacent hollow hemispherical measuring templates 10 differs by 1mm.

[0036] In one embodiment, based on their specific size distribution, the plurality of hollow hemispherical measuring templates 10 can be divided into a first series and a second series. The first series may include all measuring templates 10 with an inner diameter of odd-numbered millimeters, while the second series may include all measuring templates 10 with an inner diameter of even-numbered millimeters. In practical applications, either the first series or the second series of hollow hemispherical measuring templates 10 can be flexibly selected as needed, and no specific limitation is imposed.

[0037] For example, in one typical application scenario, please refer to Figure 2 Taking the first series of multiple hollow hemispherical measuring templates 10 as an example, the first series can include a total of 9 hollow hemispherical measuring templates 10. The specific dimensions of the 9 hollow hemispherical measuring templates 10 can be found in the table below.

[0038] Table 1: Size distribution of multiple hollow hemispherical measurement templates 10 in the first series

[0039] In Table 1, dimension A represents the maximum inner diameter of a single hollow hemisphere measuring template 10, dimension B represents the depth of a single hollow hemisphere measuring template 10, and dimension C represents the height of the hollow hemisphere measuring template 10. The units of dimensions A, B, and C are all millimeters.

[0040] In one embodiment, the femoral head size measurement hemispherical template kit may further include an acetabular mold (not shown in the figure), which can be used in conjunction with the aforementioned plurality of hollow hemispherical measurement templates 10. Specifically, the radius of curvature of the acetabular mold's inner cavity matches that of a femoral head prosthesis of the same nominal diameter, for use in vacuum adsorption testing after measurement.

[0041] It should be noted that, in this embodiment, when using the femoral head size measuring hemispherical template kit to measure the femoral head size, one can hold the femoral head with one hand and select a measuring template 10 that is 2–3 mm larger than the visual estimate with the other hand, and then slowly push it down perpendicular to the long axis (equatorial plane) of the femoral head.

[0042] If the femoral head can move freely within the measuring template 10, replace it with a smaller measuring template 10. If the femoral head is stuck or cannot enter the measuring template 10, replace it with a larger measuring template 10, until a measuring template 10 is found where "the femoral head fits snugly against the inner wall of the measuring template 10 without significant movement." When recording readings, the inner diameter of the measuring template 10 that finally passes through is taken as the FHD, accurate to 1 mm. If the size is between two measuring templates 10, the smaller one should be chosen to prevent excessive reaming of the acetabulum, which could lead to loosening later.

[0043] Based on the above settings, in this embodiment, the femoral head size measurement hemispherical template kit has at least the following beneficial effects: First, it has a high degree of geometric fit. The femoral head is regarded as a complete sphere, and its size is measured directly from a three-dimensional level using a hollow hemispherical measuring template 10, avoiding directional errors caused by "non-spherical" or cartilage residue.

[0044] Secondly, the operation is extremely simple and requires no special equipment. Simply place the removed femoral head directly into the measuring template 10, take the reading, and select the corresponding prosthesis. The average time is less than 30 seconds, which is significantly faster than 3D scanning or navigation positioning.

[0045] Furthermore, since the measuring template 10 is made of transparent, slightly stretchable 3D printing material, irregularly damaged femoral heads can be directly placed into the measuring ball, thus allowing for a direct view of the defect and the size of the femoral head.

[0046] Furthermore, the measuring template 10 is designed to match the acetabular cup, minimizing the matching error. Commercial acetabular cups are inherently truncated hemispheres of 165°–180°, and the diameter measured by the measuring template 10 directly corresponds to the manufacturer's "head-cup" matching table, which helps improve the fit rate.

[0047] Finally, the cost is relatively much lower and the repeatability is high. Because it does not rely on CT, navigation, or laser scanning, it saves on preoperative imaging costs and avoids systematic biases caused by differences in equipment calibration, making it particularly friendly to primary hospitals.

[0048] Please see Figure 3 This invention also provides a method for measuring the size of an isolated femoral head, which can be applied to the above-mentioned femoral head size measurement hemispherical template kit, and includes the following steps: S1. Provide an isolated femoral head sample, the surface of which has been freed of soft tissue and cartilage covering.

[0049] S2. Based on the visual estimation of the size of the femoral head sample, select a measurement template 10 from the hemispherical template kit with an inner diameter larger than the estimated size.

[0050] S3. Push the femoral head sample into the cavity from the opening 111 of the selected measuring template 10 along the long axis direction.

[0051] S4. Fit judgment: If the femoral head sample has obvious movement gap in the cavity, replace it with a measuring template 10 with a smaller inner diameter and repeat step S3; if the femoral head sample cannot completely enter the cavity or encounters too much resistance during the entry process, replace it with a measuring template 10 with a larger inner diameter and repeat step S3.

[0052] S5. Determine the measurement results: until a measurement template 10 is found that allows the femoral head sample to fit in a way that does not cause significant shaking after being placed in it, and the light is uniformly transmitted around the interior of the hemispherical shell 11 and the femoral head sample. Record the inner diameter value of the measurement template 10 as the diameter data of the femoral head sample.

[0053] It should be noted that when selecting the measurement template 10 based on the estimated dimensions, one can start by selecting a template 10 that is 2-3 sizes larger than the estimated dimensions of the wall by visual inspection. Then, decrease the size by 1mm each time until a suitable measurement template 10 is found. During this process, avoid skipping numbers or reversing the order to prevent missing the desired measurement template 10 and resulting in repeated measurements.

[0054] In one embodiment, in step S3 above, when the femoral head sample is pushed into the measuring template 10, the axis of the bottom opening 111 of the measuring template 10 must pass through the center of the measured cross section of the femoral head sample; statistically, it has been found that if the axis deviates from the equatorial diameter by more than 5°, it will usually introduce a positive error of 0.2-0.3 mm.

[0055] Meanwhile, the pushing action in step S3 above may include the following steps: after the femoral head sample is pushed into the cavity, it is rotated 30° to 60° around its long axis, and the slight extensibility of the hemispherical shell 11 is used to adapt to the slight irregularities on the surface of the femoral head sample in order to verify the overall fit.

[0056] In addition, it should be noted that during actual operation, at the moment when the measuring template 10 contacts the femoral head, a combination of "push-rotate" can be used. First, push the femoral head sample to the desired position, and then rotate it to the left or right, or first to the left and then to the right at a specified angle (such as 30°). Finally, confirm the fit between the femoral head sample and the inner wall of the measuring template 10. During this process, direct pressure should be avoided to prevent the femoral head sample from splitting or micro-cracks at the junction of the head and neck.

[0057] When actually confirming the fit between the femoral head sample and the inner wall of the measuring template 10, the light transmission between the inside of the hemispherical shell 11 and the femoral head sample can be observed to see if the light transmission is uniform. If there is no visible gap between the measuring template 10 and the arc surface of the femoral head sample and the light transmission in the four quadrants is the same, the size can be determined. If one side is bright and the other side is dark, it means that the largest equatorial circle has not been found and the above steps S4-S5 need to be repeated.

[0058] In one embodiment, when determining the diameter of the femoral head sample, the measurement method further includes the following steps: S6. Vacuum Adsorption Verification: Place the femoral head sample with the diameter data determined in step S5 into the inner cavity of the acetabular mold with the same diameter value. Apply axial pressure to expel the air and then remove the external force. Observe whether the femoral head sample is kept in the acetabular mold due to the negative pressure and does not fall off immediately. If the femoral head sample cannot maintain the adsorption state in the acetabular mold or falls off too early, select a measuring template 10 with a smaller inner diameter and repeat step S5.

[0059] It should be noted that the femoral head sample used in this embodiment has had its soft tissue and cartilage covering removed; at the same time, before officially starting the relevant operations, it is preferable to remove cartilage debris with a damp gauze to avoid "sand grains" getting stuck between the femoral head sample and the inner wall of the measuring template 10 during measurement, causing mirror scratches.

[0060] Meanwhile, since high-temperature and high-pressure sterilization may cause the inner diameter of the measuring template 10 to expand (usually by 0.01-0.02 mm each time), the measuring template 10 should be re-inspected regularly. If the error of the inner diameter of the measuring template 10 exceeds 0.05 mm, it should be scrapped to ensure the accuracy of the spare measuring template 10.

[0061] In addition, the measuring template 10 can be cleaned again after use to prevent stress corrosion from causing pitting. It is also preferred to store it in a single layer to avoid collisions that could cause gaps or deformation.

[0062] It should be particularly noted that the embodiments of the present invention actually provide a method for measuring the size of isolated femoral heads. This method is mainly described in this embodiment for isolated femoral head samples (as opposed to those used during surgery). Although this method can also be used by doctors during surgery, the measurement method described in the embodiments of the present invention is limited to the size measurement of isolated femoral head samples for non-therapeutic purposes. It does not include surgical steps that directly act on the human body for treatment, nor does it include the diagnosis and treatment process of diseases.

[0063] Based on this, to facilitate understanding of how the measurement method provided in the embodiments of the present invention is specifically applied in a clinical setting, the embodiments of the present invention also provide the following clinical application scenario examples, which may include the following steps: Taking a total hip replacement surgery as an example, the patient suffered from avascular necrosis of the femoral head, with cystic changes and local collapse on the surface of the femoral head, resulting in an extremely irregular shape. During the operation, after the femoral head was dislocated from the acetabulum, it was carefully removed intact to avoid secondary cutting with bone forceps, which could cause spherical destruction. Simultaneously, the surface cartilage, synovium, and osteophytes could be gently scraped away with gauze or the back of a scalpel until the hard cortical bone shell was exposed. Care should be taken not to excessively grind it, as this could artificially reduce its size. After rinsing with saline solution, the femoral head was dried with gauze to minimize frictional errors.

[0064] After completing the above preparations, the doctor can hold the femoral head in one hand and select a measuring template 10 that is 2-3 mm larger than the visually estimated size of the femoral head in the other hand. The measuring template 10 is then slowly pushed down perpendicular to the long axis (equatorial plane) of the femoral head. If the femoral head can move freely in the measuring template 10, a smaller measuring template 10 is used. If the femoral head is stuck or cannot enter the measuring template 10, a larger measuring template 10 is used until a measuring template 10 that fits perfectly without significant wobbling is found.

[0065] When recording readings, the inner diameter of the final measured template 10 can be used as FHD, accurate to 1mm; if the determined diameter of the femoral head is between the sizes corresponding to the two measured templates 10, the smaller one should be selected according to the principle of "choosing the smaller one" to prevent excessive reaming of the acetabulum leading to loosening later.

[0066] In addition, the determined femoral head dimensions can be verified intraoperatively. Specifically, the measured femoral head can be placed into an acetabular mold of the same size as the measuring template 10, and the air should be gently vented. If the femoral head is "sucked" in and does not immediately fall off after release, it indicates a good fit. If the vacuum suction is poor, the size of the acetabular mold should be reduced by 1 mm and refitted to ensure that the contact area between the inner wall of the acetabular cup and the outer surface of the femoral head prosthesis is maximized during the operation, thereby reducing point stress.

[0067] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A hemispherical template kit for measuring femoral head size, characterized in that, Including multiple hollow hemispherical measuring templates with increasing inner diameter; The hollow hemispherical measuring template includes a hemispherical shell, the bottom of which has an opening for the femoral head sample to enter, and the interior has a cavity for accommodating the femoral head sample. The hemispherical shell is made of a transparent and flexible biocompatible material, which is configured to undergo elastic deformation under stress and return to its original shape after the stress is removed, and is able to withstand high-temperature sterilization. The inner diameter of the plurality of hollow hemispherical measuring templates covers a preset range of femoral head diameters, and the difference in the inner diameter of any two adjacent hollow hemispherical measuring templates is a preset step size.

2. The femoral head size measurement hemispherical template kit according to claim 1, characterized in that, The biocompatible material is any one of medical-grade thermoplastic polyurethane (TPU), medical-grade silicone, and a rubber-like photosensitive resin with a Shore hardness of A60-90.

3. The femoral head size measurement hemispherical template kit according to claim 1, characterized in that, The opening edge of the hemispherical shell is blunted to form a rounded corner with a radius of 0.2 mm to 0.5 mm to prevent scratching the surface of the femoral head sample during measurement.

4. The femoral head size measurement hemispherical template kit according to claim 1, characterized in that, The preset step size is 1 mm; the multiple hollow hemispherical measuring templates are divided into a first series and a second series. The first series includes measuring templates with an inner diameter of odd millimeters, and the second series includes measuring templates with an inner diameter of even millimeters.

5. The femoral head size measurement hemispherical template kit according to claim 1, characterized in that, The wall thickness of the hemispherical shell is 1.5 mm to 3 mm, and the outer surface or open end face of the hemispherical shell is marked with a numerical mark corresponding to its inner diameter.

6. The femoral head size measurement hemispherical template kit according to claim 1, characterized in that, The opening diameter of the hollow hemispherical measuring template is greater than or equal to its maximum inner diameter, so that the femoral head sample can be completely inserted into the cavity from the opening until its equatorial plane is flush with or nearly flush with the opening end face.

7. The femoral head size measuring hemispherical template kit according to any one of claims 1-6, characterized in that, The kit also includes an acetabular test mold used in conjunction with the plurality of hollow hemispherical measurement templates. The radius of curvature of the acetabular test mold is matched with the femoral head prosthesis of the same nominal diameter for use in vacuum adsorption testing after measurement.

8. A method for measuring the dimensions of an isolated femoral head based on a hemispherical template kit according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Provide an isolated femoral head sample, the surface of which has been freed of soft tissue and cartilage covering; S2. Based on the visual estimation of the size of the femoral head sample, select a measurement template from the hemispherical template kit whose inner diameter is larger than the estimated size; S3. Push the femoral head sample into the cavity from the opening of the selected measuring template along the long axis direction. S4. Fit judgment: If the femoral head sample has obvious movement gap in the cavity, replace it with a measuring template with a smaller inner diameter and repeat step S3; if the femoral head sample cannot completely enter the cavity or encounters too much resistance during the entry process, replace it with a measuring template with a larger inner diameter and repeat step S3. S5. Determine the measurement results: until a measurement template is found that allows the femoral head sample to fit snugly against the inner wall of the measurement template without significant movement, and the light transmission between the interior and the femoral head sample is uniform through the hemispherical shell. Record the inner diameter value of the measurement template as the diameter data of the femoral head sample.

9. The measurement method according to claim 8, characterized in that, In step S3, the pushing action includes the following steps: After the femoral head sample is pushed into the cavity, it is rotated 30° to 60° around its long axis. The slight extensibility of the hemispherical shell is used to adapt to the slight irregularities on the surface of the femoral head sample in order to verify the overall fit.

10. The measurement method according to claim 8, characterized in that, The measurement method further includes the following steps: S6. Vacuum adsorption verification: Place the femoral head sample with the diameter data determined in step S5 into the inner cavity of the acetabular mold with the same diameter data. Apply axial pressure to expel the air and then remove the external force. Observe whether the femoral head sample is kept in the acetabular mold due to the negative pressure and does not fall off immediately. If the femoral head sample cannot maintain its adsorption state in the acetabular mold or falls off prematurely, select a measuring template with a smaller inner diameter and repeat step S5.

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