JP6480262B2 - Medical trochanteric implant - Google Patents

Description

The present invention also relates to a medical trochanter alternative in plant.

The hip joint is a joint at the base of the leg and is between the trunk and the leg. The hip joint plays a role of supporting weight when a person stands or walks. The hip joint is about 3 times the weight when walking, about 6 to 7 times the weight when standing, and a slightly lower position such as the floor. It is said that it takes 10 times as much weight as the body from the start.
In the hip joint, the spherical portion of the femur (the femoral head) is fitted into the concave portion (acetabulum) forming the spherical seat of the pelvis. The joint part, that is, the surface of the femoral head is covered with cartilage, and absorbs the weight and force applied to the above-mentioned hip joint, and facilitates the movement of the femoral head and the acetabulum.

As diseases that cause damage to the hip joint due to some cause and cause pain in the hip joint, osteoarthritis, rheumatoid arthritis, bone head necrosis, and the like are well known. In these diseases, hip replacement is performed when hip pain is not alleviated even after conservative therapy, or when symptoms are considerably advanced. In addition, hip replacement is also performed when the proximal femur fractures due to falls or the like.
Hip replacement is an operation in which worn cartilage and damaged bone are removed and replaced with a metal or plastic hip joint.

The artificial hip joint includes a metal cup, a head ball, and a member called a stem, and a plastic liner serving as a substitute for cartilage is fitted inside the cup.
For example, Patent Document 1 has a bone tissue intrusion fixing portion in which a plurality of grooves are formed on the surface of a medical implant, and all or part of the bone tissue intrusion fixing portion is other than the bone tissue intrusion fixing portion. A configuration is disclosed that is raised so that it rises higher than the surface of the medical implant.
The medical implant described in Patent Document 1 has a bone tissue intrusion fixing portion in which a plurality of grooves are formed. Therefore, the medical implant has excellent adhesion and fixation with a bone, and all or part of the bone tissue intrusion fixing portion is raised. Because it is excellent in strength.

JP 2007-296250 A

  In recent years, the number of hip replacements has been increasing, and with the increase of hip replacements, the number of patients who have fractures around the hip prosthesis or the proximal femur has been increasing rapidly. For example, approximately 4% of patients who have undergone hip replacement have been reported to cause periprosthetic fractures (Neumann et al., 2012).

  However, if a patient who has already had a hip prosthesis has a fracture, the already implanted hip prosthesis must be removed and replaced with a new hip prosthesis. At that time, as shown in FIGS. 1 (a) and 1 (b), when trying to remove a conventional artificial hip joint including the medical implant disclosed in Patent Document 1 from the lumen S of the femur B, , The greater trochanter C1 and the inner trochanter C2 projecting to the outer side in the circumferential direction of the femur B (that is, the right side and the left side in FIGS. 1A to 1C) hit the stem 12, and are difficult to remove. . Further, when the artificial joint is well fixed, the bones of the artificial hip joint and the greater trochanter C1 and the inner trochanter C2 are fixed, making it difficult to remove. Therefore, conventionally, the greater trochanter C1 and the inner trochanter C2 are broken by using a tool such as a heel and the corresponding part of the artificial hip joint such as the stem 12 is inserted into and removed from the lumen S of the femur B. After the artificial hip joint is re-replaced in this way, as shown in FIG. 1 (c), the treatment is completed while the greater trochanter C1 and the inner trochanter C2 are missing, or the greater trochanter C1 destroyed. In addition, an appropriate material (not shown) may be provided at the position of the inner trochanter C2.

However, if the trochanter D including the greater trochanter C1 and the inner trochanter C2 is missing, or if the embedded material is insufficient for the good functioning of the bone, The portion where the trochanter D is missing (ie, the missing portion X in FIG. 1 (c)) is likely to be burdened, the bone around the missing portion X is weakened, and the femur and pelvis are distorted and displaced. Other complications occurred.
Thus, conventionally, there is a medical trochanteric implant that can be applied to cases where bones around the stem 12 of the hip prosthesis (for example, the greater trochanter C1 and the inner trochanter C2) are broken and replaced. There was no problem. Moreover, although the method of winding a wire etc. around the defect part X is also employed, there is a problem that much winding time and labor of the practitioner are spent. In the above description, the hip joint is exemplified as one of the joints. However, the above-described problem is a joint that can be replaced with an artificial joint, and may occur similarly in a joint such as a knee joint or an elbow joint.

The present invention was made to solve the above problems, to provide a readily reinforced medical trochanter alternative in plant the lost portion of the trochanter.

The medical trochanteric substitute implant of the present invention is a medical trochanteric substitute implant that is installed on a bone having a trochanter part including a greater trochanter and a smaller trochanter, and replaces the missing part of the trochanter part. A trochanter replacement part, and a stem, the proximal end of the stem being connectable to the trochanter replacement part, the distal end of the stem being insertable into the bone lumen, the width dimension of the small toward the tip, the rotor alternatives, the stem and can be inserted stem through hole is formed, the engageable of said stem to the distal end of the stem insertion hole When the locking portion is locked, a gap is generated between the stem proximal to the locked portion and the inner peripheral surface of the stem insertion hole, and the trochanter replacement portion and the proximal end portion of the stem In the connected state, the trochanter replacement portion is configured to disengage the locked portion with respect to the proximal end portion of the stem Characterized in that it is movable as a heart.

  In the medical trochanteric substitute implant of the present invention, the trochanteric substitute part is provided with a bone connecting part connectable to the proximal part of the bone, and bulging from the bone connecting part to the outer peripheral surface of the bone It is preferable to include a greater trochanter substitute portion and a smaller trochanter substitute portion.

In the above-described medical trochanteric substitute implant, it is preferable that the trochanteric substitute part is provided with a ligament connection part in which an artificial ligament to which a ligament can be attached is knitted.
Moreover, the ligament attachment part which can be connected and fixed to the cut | disconnected ligament is provided in the other edge part on the opposite side to the one edge part in which the said ligament connection part is provided in the said artificial ligament. It is preferable.

According to the medical trochanteric substitute implant of the present invention, during surgical treatment with artificial joint re-replacement, the defect of the trochanter that is missing when the conventional artificial joint previously installed before the start of treatment is removed The part can be easily replaced with a medical trochanteric substitute implant. Therefore, it solves the problems such as applying excessive force to the bone, or weakening the bone around the trochanter defect, as in the state of leaving the defect, and early repair of the bone and ligament. Can be planned .

It is the schematic which shows a mode that the conventional hip prosthesis is re-replaced by the femur, (a) shows the state where the small trochanter has hit the stem, (b) has the great trochanter hits the stem The state is shown, and (c) shows a state in which the greater trochanter and the lesser trochanter are missing. It is a figure which shows the medical trochanter substitute implant which is 1st embodiment of this invention. It is the schematic for demonstrating the assembly method of the medical trochanter substitute implant which is one Embodiment of this invention. It is a figure which shows the finite element model corresponding to the case where it sees from the front of the medical trochanter substitute implant used in Example 1, (a) is a movable type model, (b) is a fixed type model. It is. It is a measurement result regarding the movable type real model in Example 2, and each of (a) to (e) and (f) to (j) is a stem at each of “inside” and “outside” of the stem. Is the measurement result from the first stage to the fifth stage in order from the trochanter alternative part side when the axis is divided into five stages in the axial direction. It is a measurement result regarding the immobility type real model in Example 2, and each of (a) to (e) and (f) to (j) is a trochanter when the stem is divided into five stages in the axial direction. The measurement results from the first stage to the fifth stage in order from the alternative part side. In Example 2, it is the graph which extracted the pressure value inside a stem for every step number, (a) is a movable type, (b) is a stationary type.

  Hereinafter, a medical trochanteric substitute implant which is an embodiment of the present invention and an assembly method of the medical trochanteric substitute implant will be described with reference to the drawings. The drawings used in the following description are schematic, and the length, width, thickness ratio, and the like are not necessarily the same as actual ones, and can be changed as appropriate.

(First embodiment)
FIG. 2 is a schematic view of a medical trochanteric substitute implant 1A according to a first embodiment to which the present invention is applied.
As shown in FIGS. 1 (a) to 1 (c), the medical trochanteric substitute implant 1A has a greater trochanter C1 and a smaller trochanter C2 by treatment of revision of an artificial hip joint (prosthetic joint) including a stem 12 or the like. The medical implant provided in the femur (bone) B lacking the trochanter part D including the trochanter part D, as shown in FIG.

The above artificial hip joint has a known configuration, for example, as shown in FIG. 1, a cup, a liner, a head ball 15 and a head ball having a shape that can be spherically fitted to an acetabulum in a pelvis (not shown). 15 and a stem 12 connectable via a neck portion 14. In FIG. 1, the cup and the liner are omitted.
The acetabulum forms a spherical seat, and a cup, liner, and head ball 15 are fitted along a spherical surface inside the spherical seat. By this spherical fitting, the artificial hip joint can be rotated with respect to the pelvis.

  The stem 12 is a part that is inserted and fixed in the lumen S of the femur in an artificial hip joint (see FIG. 5), and is a member having a predetermined length. As shown in FIGS. 1A to 1C, the proximal end of the stem 12 (that is, the upper end shown in FIGS. 1A to 1C) 12a has the stem 12 toward the pelvis. A neck portion 14 is continuously provided in a direction inclined from the extending direction. On the other hand, the width dimension of the distal end portion (ie, the lower end portion shown in FIG. 1) 12b of the stem 12 is made smaller toward the tip. By having such a tapered shape, the stem 12 can be easily inserted into the lumen S of the femur B from the distal end 12b.

  The material of the artificial hip joint is not particularly limited, but a metal excellent in biocompatibility is preferable. Examples of such a metal include a titanium alloy (for example, Ti—Al—V alloy, Ti—Ni alloy), single titanium, stainless steel (SUS316, etc.).

  The trochanter replacement part 2 is a part that replaces the missing part X of the trochanter part D that has been lost by hitting the stem 12 described above, for example. As shown in FIG. 2, the trochanter replacement part 2 and the greater trochanter substitute A portion 4, a lesser trochanter substitute portion 6, and a ligament connection portion 8 are provided.

  The bone connecting portion 3 is a portion that can be connected to at least the femur B. If the connected surface 5p provided in the defect portion X (omitted in FIG. 2) of the femur B is relatively smooth, it is preferable that the bone connecting portion 3 can be brought into contact with the connected surface 5p. . However, when the trochanter part D is destroyed by the treatment of replacement of the artificial hip joint or the like, the connected surface 5p is often a surface having a plurality of irregularities regardless of the size. What is necessary is just to be able to connect with the proximal part A which touches the defect | deletion part X of the femur B. FIG.

  Specifically, the bone connecting portion 3 is formed in a top tube shape, and includes a ceiling wall that forms a connecting surface 3p that can be connected to the connected surface 5p, and a side wall 3s that rises vertically from the ceiling wall. ing. The shape of the connecting surface 3p is formed so as to be engageable with the shape of the connected surface 5p. The inner peripheral size and the cross-sectional shape of the side wall 3s are formed in accordance with the outer peripheral size and the cross-sectional shape of the proximal portion A of the femur B. That is, the bone connecting portion 3 is a so-called lid portion, and is fitted to the proximal portion A of the femur B so as to be in contact with the surface to be connected 5p and connectable to the femur B. An appropriate buffer or adhesive may be interposed between the connection surface 3p and the connection surface 5p.

  The greater trochanter replacement part 4 is formed so as to protrude from the bone connecting part 3 in one direction (that is, on the proximal side and upward in FIG. 2) and bulge with respect to the outer peripheral surface of the femur B. Has been. Since the greater trochanter substitute portion 4 is formed in such a shape, the greater trochanter substitute portion 4 replaces the missing greater trochanter C1 and stably receives the load applied to the femur B. Can be dispersed throughout the femur B.

  The small trochanter replacement portion 6 projects in one direction from the bone connecting portion 3 in the same manner as the large trochanter replacement portion 4 and is large with respect to the outer peripheral surface of the femur B around the axis J of the femur B. It is formed so as to bulge in a direction substantially opposite to the trochanter replacement portion 4. Since the small trochanter replacement part 6 is formed in such a shape, the missing small trochanter C2 can be replaced, and the load applied to the femur B together with the large trochanter replacement part 4 can be stably received, The load can be distributed throughout the femur B.

  Although the material of the bone connection part 3, the greater trochanter substitute part 4, and the lesser trochanter substitute part 6 is not specifically limited, The metal excellent in biocompatibility is preferable. Examples of such metals include titanium alloys (for example, Ti—Al—V alloys, Ti—Ni alloys), single titanium, stainless steel (SUS316, etc.), as well as suitable metals constituting the artificial hip joint 10. It is done.

  The ligament connection portion 8 is a ligament (not shown) cut as shown in FIG. 2 by, for example, removal of an artificial hip joint previously provided before the medical trochanteric substitute implant 1A is provided on the femur B. ) To which the artificial ligament 20 can be attached. The ligament connection portion 8 is provided at the upper end portion of the trochanter replacement portion 2, that is, the upper end portions of the large trochanter replacement portion 4 and the small trochanter replacement portion 6. However, as long as the artificial ligament 20 can be knitted, the ligament connection portion 8 may be provided at an arbitrary position of the trochanter replacement portion 2.

  One end 20a of the artificial ligament 20 is knitted in the ligament connecting portion 8. The other end portion 20b of the artificial ligament 20 is provided with a ligament attachment portion 22 that can be connected to and fixed to the cut ligament. Specifically, the ligament attachment portion 22 includes a base plate 26 connected to the end portion 20b, a screw 24 attached to the base plate 26, and an insertion portion 28. The trochanter replacement part 2 is connected to the cut ligament via the artificial ligament 20 by embedding the screw portion and the insertion portion 28 of the screw 24 in the ligament and fixing the base plate 26 to the ligament.

According to the medical trochanteric substitute implant 1A of the first embodiment described above, for example, during a surgical treatment involving hip replacement, when a conventional hip prosthesis previously installed before the start of treatment is removed. The missing part X of the missing trochanter part D can be replaced by the trochanter replacement part 2.
Accordingly, it is possible to solve problems such as applying excessive force to the femur B or weakening the bone around the defect portion X while leaving the defect portion X as in the prior art. Early repair can be achieved.

  Further, according to the medical trochanter substitute implant 1A of the first embodiment, the missing part X of the greater trochanter C1 and the lesser trochanter C2 can be easily replaced by the greater trochanter substitute 4 and the less trochanter substitute 6 respectively. can do. Further, the greater trochanter substitute 4 and the lesser trochanter substitute 6 are connected to the femoral bone B by the bone connecting portion 3 provided integrally connected to the greater trochanter substitute 4 and the lesser trochanter substitute 6. The lumen S can be stably inserted and fixed.

  Moreover, according to the medical trochanteric substitute implant 1A of the first embodiment, since the ligament connection part 8 is provided in the trochanteric replacement part 2, the artificial ligament 20 knitted in the ligament connection part 8 is, for example, surgical It is possible to easily attach a ligament or the like that has been cut during physical treatment. Thereby, early repair of a bone and a ligament can be promoted more.

(Second embodiment)
A medical trochanteric substitute implant 1B according to a second embodiment to which the present invention is applied includes a trochanteric substitute portion 2P and a stem 30. In the following description and the components of the medical trochanteric substitute implant 1B shown in FIG. 3, the same configurations as those of the femur B and the medical trochanteric substitute implant 1A shown in FIGS. Elements are denoted by the same reference numerals and description thereof is omitted.

  FIG. 3 is a schematic view of the medical trochanteric substitute implant 1B, (a) is a view showing a state before the stem 30 is connected to the trochanteric substitute part 2P, and (b) is a diagram showing the trochanteric substitute part 2P. It is a figure which shows the state after connecting the stem 30, (c) shows the movable direction of the trochanter substitute part 2P with respect to the base end part of the stem 30 in the state after connecting the stem 30 to the trochanter substitute part 2P. FIG.

The trochanter replacement part 2P has the same configuration as the trochanter replacement part 2 of the first embodiment. In FIG. 3, the ligament connecting portion 8 is omitted.
Furthermore, a stem insertion hole 34 is formed in the trochanter replacement part 2P of the second embodiment along the axis J of the femur not shown in FIG. The proximal end 34 a of the stem insertion hole 34 opens at the upper end of the trochanter substitute 2, that is, the upper ends of the large trochanter substitute 4 and the small trochanter substitute 6. The distal end 34 b of the stem insertion hole 34 is open to the connection surface 3 p of the bone connection part 3. And the width dimension of the stem insertion hole 34 is made small as it goes to the connection surface 3p of the bone connection part 3 along the axis line J from the upper end part of the trochanter alternative part 2. As shown in FIG.

  Similar to the generally known stem 12 of an artificial hip joint (see FIGS. 1A to 1C), the stem 30 is changed from a proximal end portion 30a to a distal end portion (tip) 30b. The width dimension is smaller toward the opposite side, and the so-called tapered shape is formed. For example, when the femur is fractured, the length of the stem 30 is a so-called re-replacement long stem that can reach the fractured portion of the tip 30b when inserted into the femur. Preferably it is. That is, the length dimension of the stem 30 is appropriately set in consideration of the damage factor and state of the femur, which is the installation target of the medical trochanteric substitute implant 1B, and is not particularly limited.

  A stem attachment portion 31 for attaching the stem 30 to the neck portion 14 (see FIGS. 1A to 1C) of the artificial hip joint is provided at the proximal end portion 30a of the stem 30. The width of the base end portion 30a of the stem 30 is such that the stem 30 can be inserted into the stem insertion hole 34 and the stem mounting portion 31 protrudes from the proximal end portion 34a of the stem insertion hole 34. The stem 30 is locked to the distal end 34b. Specifically, the width dimension of the stem 30 decreases at a predetermined rate from the locked portion 35 of the stem 30 locked to the distal end portion 34b toward the distal end portion 34b. On the other hand, the width dimension of the stem 30 increases at a rate larger than the predetermined rate from the locked portion 35 of the stem 30 toward the proximal end portion 34a.

Figure 3 (c), the the distal end portion engaging portion 35 to 34 b of the stem through hole 34 is engaged, proximal stem 30 and the end than engaging portion 35 A gap is generated between the portion 34 a and the inner peripheral surface of the stem insertion hole 34. In the state where the trochanter replacement part 2 and the stem 30 are connected as described above, for example, the trochanter replacement part 2P is shown in FIG. 3C with respect to the base end part 30a of the stem 30 by the gap. As described above, it is possible to move in the arrow D1 direction along the long side direction of the stem insertion hole 34 with the locked portion 35 as the center.
Further, by making the shape of the stem insertion hole 34 in a plan view, for example, a perfect circle or the like, the trochanter replacement part 2P is in the direction of the arrow D1 along the long side direction of the stem insertion hole 34 with the locked part 35 of the stem 30 as the center. It can also be moved to. That is, the stem insertion hole 34 is preferably formed to have a shape corresponding to a desired region for moving the trochanter replacement portion 2P around the locked portion 35 of the stem 30.

  The material of the stem 30 is not particularly limited, but a metal excellent in biocompatibility is preferable. Examples of such metals include titanium alloys (for example, Ti—Al—V alloys, Ti—Ni alloys), single titanium, stainless steel (SUS316, etc.), as well as suitable metals constituting the artificial hip joint 10. It is done.

Next, a method for assembling the medical trochanteric substitute implant 1B will be described with reference to FIG.
When assembling the medical trochanteric substitute implant 1B, first, the bone connecting part 3 of the trochanteric substitute part 2P is externally fitted to the proximal part A (not shown in FIG. 3) of the femur B.
Subsequently, as shown in FIG. 3A, the distal end portion 30b of the tapered stem 30 is inserted into the stem insertion hole 34 from above the trochanter replacement portion 2P, and as shown in FIG. The stem 30 is advanced until the locking portion 35 is locked in the stem insertion hole 34. In this way, the trochanter replacement part 2P and the base end part 30a of the stem 30 can be connected. At the same time, the tip 30b of the stem 30 can be inserted into the lumen of the femur.
Through the above operations, the medical trochanteric substitute implant 1B shown in FIG. 1 is assembled.

  The medical trochanter replacement implant 1B of the second embodiment described above includes the trochanter replacement portion 2P and the stem 30, so that the missing portion X of the trochanter portion D is replaced by the trochanter replacement portion 2P. At the same time, a stem 30 that can be connected to the trochanter replacement part 2P is connected, and the stem 30 can be inserted into the lumen S of the femur B. That is, according to the medical trochanteric substitute implant 1B of the second embodiment, the trochanteric substitute part 2P has the ability to grip the proximal end of the stem similar to the artificial joint conventionally used, and the defect Part X can be reinforced.

Further, according to the medical trochanteric substitute implant 1B of the second embodiment, since the stem insertion hole 34 is formed in the trochanteric replacement portion 2P, the stem 30 is inserted into the stem insertion hole 34 and locked. In this case, the stem 30 can be connected to the trochanter replacement part 2P.
Further, according to the medical trochanter replacement implant 1B of the second embodiment, the trochanter replacement can be performed by appropriately changing the size and shape of the opening of the stem insertion hole 34 and the width and cross section of the stem 30. The part 2P can be moved with respect to the proximal end part 30a of the stem 30, and the trochanter replacement part 2P can be more suitably arranged according to the shape of the femur B, the slight curvature of the lumen S, and the like.

  Further, according to the method for assembling the medical trochanter replacement implant 1B described above, the distal end portion 30b of the stem 30 is inserted into the stem insertion hole 34 from above the trochanter replacement portion 2P and is locked to the stem insertion hole 34. The medical trochanteric substitute implant 1B can be easily assembled only by advancing the stem 30 until it reaches the desired position. Therefore, it is possible to reduce the time and labor required for a person who installs the medical trochanteric substitute implant 1B on the femur B.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications are possible within the scope of the gist of the present invention described in the claims. Deformation / change is possible.

For example, in the medical trochanteric substitute implants 1A and 1B, the bone connection part 3, the greater trochanter substitute part 4, and the lesser trochanter substitute part 6 may be integrated.
Further, the medical trochanter replacement implants 1A and 1B include the greater trochanter replacement portion 4 and the smaller trochanter replacement portion 6 according to the damaged state of the femur B to be installed, the size of the defect portion X, and the like. Only one of them may be provided.
Further, the medical trochanteric substitute implants 1A and 1B may not include the ligament connection portion 8, and have a configuration different from that of the ligament connection portion 8 described above, and can be connected to a predetermined site in the body. A connecting portion (not shown) may be provided.

  Next, the present invention will be described in detail by the following examples, but the present invention is not limited to these examples.

Example 1
A finite element model similar to the medical trochanter substitute implant 1B of the second embodiment shown in FIG. 3 was constructed and finite element analysis was performed. The movable type shown in FIG. 4A and the non-moving type shown in FIG. 4B were used for the finite element model in this example. The number of elements in the finite element analysis is 2629 for the movable type and 2571 for the non-moving type. The number of nodes in the finite element analysis is 4844 for both the movable type and the non-movable type.
Further, the load condition was that a step load of 650 N (1 BW) was applied to the proximal end portion of the stem 30, that is, the proximal end portion 30 a for 10 seconds. 520 N was applied to the proximal part A of the femur B as the abductor muscle force.

  The material constants shown in Table 1 below were adopted as materials for the medical trochanteric substitute implant 1B and the femur as titanium alloy and cancellous bone, respectively. For reference, the material constants of cortical bone are also listed in Table 1.

4A and 4B show the stress distribution of the finite element model corresponding to each of the movable type and the non-moving type when viewed from the front. As shown in FIG. 11, it can be seen that the received pressure is more dispersed in the movable type than in the non-moving type.
In addition, the sinking is -2.300 μm for the movable type and -2.313 μm for the non-moving type, and there is no significant difference between the moving type and the non-moving type. Became lower.
From the above results, it is considered that the pressure and load received by the movable type can be more efficiently distributed to the femur than the non-moving type, and the sinking of itself can be suppressed.

(Example 2)
The actual type of movable and non-movable model of the medical trochanteric substitute implant 1B is prepared, and a tactile sensor (sold by NITTA CORPORATION) and an artificial hip joint stability tester (not for sale, manufactured by: Toyo Sanki Co., Ltd.) was used to evaluate the stability when a load was applied.
In the evaluation, in each of the movable type and non-moving type real models, the stem 30 protruding distally from the trochanter substitute portion 2P was divided into five stages in the axial direction, and the length dimension of one division was 20 mm. The direction toward the center of the patient's body at the time of implantation with the axis of the stem 30 as the center is defined as “inside”, and the direction toward the opposite side (ie, outside the patient's body) is defined as “outside”.

  FIG. 5 shows the measurement results for the movable type real model, and FIG. 6 shows the measurement results for the movable type real model. 5 and FIG. 6, (a) to (e) and (f) to (j) are respectively from the trochanter replacement part 2P side when the stem 30 is divided into five stages in the axial direction. In order, the measurement results from the first stage to the fifth stage. In addition, in each of the measurement results of (a) to (e) and (f) to (j), the same color background is added to make the color distributions of the measurement results easier to see and compare.

  When comparing (a) to (e) of FIG. 5 and (a) to (e) of FIG. 6, the first stage is shown in FIG. On the other hand, in the movable type, as shown in FIGS. 5B and 5C, a large load is received while being distributed in the second and third stages. Therefore, it can be seen that the received pressure and load are transmitted in the axial direction of the stem 30 in the movable type rather than the stationary type. On the other hand, on the outside of the stem 30, it can be seen that the received pressure and load are transmitted in the same direction in the axial direction of the stem 30 in the movable type and the non-moving type.

  FIG. 7 is a graph in which the pressure value inside is extracted for each number of stages, where (a) is a movable type and (b) is a non-moving type. As shown in FIG. 7A, in the movable type, the pressure is distributed approximately averagely in the axial direction of the stem 30. On the other hand, as shown in FIG. 7B, the pressure is high on the proximal side in the non-moving type. From these results, it can be seen that the received pressure and load are transmitted on the average in the axial direction of the stem 30 in the movable type rather than the stationary type.

(Consideration of Example 1 and Example 2)
From the results of Example 1 to Example 3 described above, the medical trochanteric substitute implant of the present invention absorbs a large load around the hip joint on the bone head and disperses it in the femur. It is assumed that the pressure at the interface with the hip joint was reduced.
In addition, it can be said that the movable type can efficiently disperse the above-described load in the longitudinal direction of the femur as compared with the non-movable type.

  As described above, according to the present invention, for example, a new medical trochanteric substitute implant that can be applied to an artificial joint of a patient who has undergone artificial joint replacement is provided. Then, during the surgical treatment of the fracture of the patient who has undergone artificial joint replacement, replace the bone part that was lost when removing the medical implant such as a conventional artificial joint that was installed before the fracture. A medical trochanteric substitute implant can also be installed.

DESCRIPTION OF SYMBOLS 1 ... Medical trochanter substitute implant 2 ... Trochanter substitute part 3 ... Bone connection part 4 ... Large trochanter substitute part 6 ... Small trochanter substitute part 8 ... Ligament connection part 30 ... Stem 34 ... Stem insertion hole B ... Femur (Bone)
S ... Lumen X ... Defect

Claims (4)

A medical trochanteric substitute implant that is placed on a bone that lacks the trochanter, including the greater trochanter and the lesser trochanter,
A trochanter replacement part that replaces the missing part of the trochanter part, and a stem,
The base end portion of the stem is connectable to the trochanter substitute portion,
The tip of the stem is insertable into the bone lumen,
The width dimension of the stem is reduced toward the tip,
The trochanter substitute part is formed with a stem insertion hole through which the stem can be inserted,
When the engaged portion of the stem to the distal end of the stem insertion hole is engaged, between the inner circumferential surface of the proximal side of the stem from the engaged portion and the stem insertion hole A gap occurs,
The trochanter for medical use in which the trochanter substitute part is movable around the locked part with respect to the base end part of the stem in a connected state between the trochanter substitute part and the base end part of the stem. Alternative implant. The trochanter replacement part is
A bone connecting portion connectable to a proximal portion of the bone;
A greater trochanter substitute portion and a lesser trochanter substitute portion provided to bulge from the bone connecting portion to the outer peripheral surface of the bone,
The medical trochanteric substitute implant according to claim 1. The trochanter substitute part is provided with a ligament connection part knitted with an artificial ligament to which a ligament can be attached,
The medical trochanteric substitute implant of Claim 1 or Claim 2. In the artificial ligament, the other end portion on the opposite side to the one end portion where the ligament connection portion is provided is provided with a ligament attachment portion that can be connected and fixed to the cut ligament,
The medical trochanteric substitute implant of Claim 3.