WO1999066865A1 - Base of a cement-free endoprosthesis for the hip joint - Google Patents

Abstract

The present invention pertains to the field of endoprostheses for the hip joint, wherein the base of this cement-free endoprosthesis is made in the form of a rod which comprises several sides and which continuously widens from its distal end towards the top on its four sides. The proximal portion of the rod comprises a pin with a conical stud, wherein the axis of the pin and the axis of the rod define together an obtuse angle, while the middle side in the proximal portion exhibits a regular curved transition towards the pin. The cross section of the rod, at least in the distal portion, is made in the shape of an isosceles trapezium having its smaller base on the middle side while the larger is on the lateral side. The convergence angle of these two sides is larger than the convergence angle defined by the back side and the front side. The middle side, in the proximal portion, comprises curved and regular chamfers which are directed towards the back and the front sides, wherein the dimensions of said chamfers increase towards the pin. The back side and the front side, in the proximal portion, include recesses having a constant depth in which flat plates made of a porous and biologically inert material are fixedly mounted. The thickness of the plates exceeds the depth of the recesses by a value which is at least equal to the pore average dimensions, said thickness representing from 20 to 200 times the pore average dimensions.

Description

\νθ 99/66865 ΡСΤ/ΕΑ98/00003

ΗΟХΚΑ BΕЗЦΕΜΕΗΤΗΟГΟ EΗDΟПΡΟΤΕЗΑ ΤΑЗΟБΕДΡΕΗΗΟГΟ SUSΤΑΒΑ

The claimed invention relates to medical technology, namely to devices that can be used for endothesis of the pelvic joints in thoracology and pediatrics.

The known stem of cementless endothesis of the hip joint is the 1_огеѷо Зпоϊогηо /1/ structure, consisting of a straight rod having a proximal end, a distal end, an anterior side, a posterior side, a medial side and a lateral side, and the pedicle expands conically from bottom to top, the proximal end of the rod contains a row of separate plates with notches between them, and both the plates and the notches are parallel to the axis of the rod, the plates are perpendicular to the lateral plane of the pedicle, and the depth of the notches increases from the medial comments about the latetal form and the maintenance of the general cognition.

The disadvantages of such a design are: the need for careful treatment of the entire internal surface of the bone-marrow canal of the femur in accordance with the conical shape of the leg, which, if possible, significantly curvature of the proximal femur due to a number of diseases is very traumatic and weakens the load-bearing capacity of the bone due to the removal of large volumes of cortical bone tissue; close fit of all the information about the canonical legs to the internal knowledge about the processing of the data of the medullary canal in the maximal part of the poor bone interferes with its normal nutrition and may interfere with its normal function Kostyn tissues; the leg of this design requires particularly precise placement and consideration of the condition of the entire surface of the bone marrow canal.

The leg of cementless endoprosthesis of the hip joint of the Bpzpioi-Muers system is known /2/, longitudinal axis and proximal 2

the area which basically corresponds to the contour of the bone marrow canal, and the proximal area has a thin pore coating to ensure osteointegration and improve secondary fixation. The disadvantages of this design are: low rotational stability during primary fixation, associated with the practically round cross-section of the distal end of the leg, which, due to micromobility, can lead to a practically complete absence, not looking for the presence of a porous coating in the apical part, osteointegration and secondary fixation; tight adherence of the entire surface of the conical and cylindrical parts of the distal end of the stem to the internal surface of the treated bone marrow canal in the proximal part of the femur disrupts its normal nutrition and can talk about the marking of bone tissues, as in the previous invention; The leg of this construction also requires special installation and taking into account the state of all information bone-brain canal.

The closest thing to the proposed technical essence and achievable positive effect is the leg cementless endothesis of the pelvic joint of the joint joint /3/, made in the form of a stanchion, Uncomfortably extending around the distal end of the vein in four gans, in the maximal part there is a neck with a conical tsaπφοο, especially the pedestal of the medial ganium of the neck is performed with a mainly linear vegetative function at the outside of the cervix 2/3 to 3/4 of yours heights.

The disadvantages of such a design are: with a sufficiently stable pres-Gϊ fixation in the distal part of the leg - weak secondary fixation in the proximal part of the leg, as evidenced by the presence of the so-called "double line" on the X-ray images over time after implantation; low anatomicality, since in a number of cases, due to the peculiarities of the anatomy of the femur of individual patients, it is possible to have a primary fit of the medial edge of the stem into the hard cortical layers near the Adams arch instead of a dense fit of the distal end of the stem into the bone the medullary canal of the femur, which will result in unstable primary fixation. The indicated shortcomings of the structure require special care and precision during installation.

The basis of the claimed invention is the task of creating a stem for endothesis of the hip joint, which would ensure equally reliable primary and secondary fixation, the resulting stability, anatomicality, low requirements for accuracy. placement, and would also promote osteointegration of the pedicle surface in the distal part - to the cortical bone tissue, and in the proximal part - to the spongy bone tissue, would expand its indications, would be less traumatic and would require removal of the establishment of a minimum volume of supporting cortical layers of the bone marrow canal.

The set goal is achieved by the fact that in the stem of the cementless endothesis of the hip joint, made in the form of a rod, continuously expanding from the distal end of the quadrant along four edges, in the proximal part of the rod a neck with a conical trunnion, the axis of the neck forms an obtuse angle with the axis of the shaft, and the medial edge in the proximal part has a smooth transition along the curvilinear surface to the neck, the cross-section of the shaft at least in the distal part has the form of an equal-femoral tapering, the smaller base which is located on the medial facet, and the larger one is on the lateral facet, and the angle of the lateral and medial facets is greater than the angle of the dorsal and anterior facets, in the proximal part on the medial facet smooth curvilinear chamfers are made to the dorsal and anterior 4

edges, the size of which increases towards the neck, on the dorsal and anterior edges in the proximal ^* part there are recesses of constant depth, in which flat plates of porous bioinert material are permanently installed, the thickness of which The depth of the excavation is not less than the average size of the hole, and is 20-200 times the average size of the hole.

The trapezoidal section of the stem with the smaller base located on the medial edge and the larger base on the lateral edge allows (while maintaining the integrity of all four main edges) to ensure reliable, stable primary fixation not only in the distal part of the stem, but also in the axial part, as it provides adequate resistance to the impact load during walking and constant contact with the spongy tissue. This will also provide, along with other distinctive features, the conditions for good secondary fixation and osteointegration in the proximal part of the leg. Trapezius section of the latter of the type indicated and more anatomically consistent with the profile of the bone marrow canal in the proximal part of the femur. The angle of convergence of the dorsal and anterior faces contributes to the optimal distribution of the load during standing and walking, and, consequently, stable fixation, as well as anatomicality even with a strongly distorted proximal part of the femur.

Curved bevels on the medial edge, increasing towards the neck, also contribute to the stability of fixation and anatomicality in any state of the cortical layers near the Adams arc. The above signs also simplify the placement of the pedicle. The excavations of constant depth in the apical part on the dorsal and anteroposterior edges, in which the flat plates made of porous bioinert material are permanently installed, contribute to achieving a positive effect. The thickness of the plates is greater depth of the recesses and is 20-200 average sizes of the pores, which ensures reliable secondary fixation due to the adhesion of spongy bone tissue into the pores to a greater depth and in sufficient volume, and due to the additional compression of the latter, it strengthens the primary fixation. >In general, this also reduces concerns about installation accuracy.

The angle of inclination of the lateral sides of the trapezoidal cross-section is 1-10°, mainly 2°.

Such limits are the most optimal from the point of view of distribution of mechanical loads (which contributes to both primary fixation and long-term stability), as well as from the point of view of anatomicality, which, in general, will undoubtedly reduce the requirements for precision of installation.

The radii of rounding of the cross-sectional edges at least in the distal part do not exceed 2 mm, mainly 1 mm.

With a larger radius of rounding of the cross section, the shortcomings inherent in known designs with a round stem appear, and with a smaller radius of 0.2-0.3 mm, there is a risk of longitudinal splitting of the femur or incomplete contact of the stem with the cortex. layers, which inevitably leads to both low anatomy and unstable fixation.

The beginning of the chamfers corresponds to the beginning of the curvilinear section on the medial edge, which additionally contributes to the stability of fixation and anatomicality. Symmetrical curvilinear chamfers of increasing size are additionally performed on the neck from the side of the trochanter, which contributes to better functioning of the prosthesis due to some increase in the degree of freedom of movement, an increase in the stability of fixation, as is guaranteed It involves hitting your feet on a cup or drinking acetabula or walking. The angle of convergence of the lateral and medial sides is 4-8°, mainly 5.5-6.5°. The angle of convergence of the dorsal and anterior sides is 1-3°, mainly 1.5-2°. The angle of convergence of the lateral and medial sides is greater than the angle of convergence of the dorsal and anterior sides by at least 2-6°, mainly by 4.0-4.5°.

The above mentioned features optimize the distribution of the mechanical load of the stem shaft on the femur, contribute to stable fixation and anatomicality. The porous plates are located in the area of intersection of the neck axis and the stem axis. The distal edge of the porous plates is located above the beginning of the curvilinear section on the medial side. The area of the porous plates is not less than half the area of the proximal part of the dorsal or anteroposterior sides. The above-mentioned signs additionally contribute to stable secondary fixation and anatomicality, as they correspond to the natural position of spongy bone tissue in the thigh.

The outer surface of the porous plates is additionally made of grooves, and the pitch and height of the grooves are 10-20 average sizes of the plates, which enhances the stability of fixation due to the increase in the contact surface.

The gap at the junction of the recess with the hollow plate, its contour is less than half the size of the white space, which does not create An increase in the adhesion of the bone tissue affects the strength of the leg and contributes to the stability of fixation.

The porous plates are made with a coating on the inner surface of a gel-like or sublimated antimicrobial preparation, and the volume of the plates is at least 60% filled with the said preparation. The outer surface of the plates is made with a thin film biocompatible hermetic coating. air and a non-toxic coating that is soluble in biological fluids. This type of implementation allows for increased fixation stability by reducing the likelihood of postoperative complications, which makes the implantation procedure itself easier. The maximal part on the latetal side is not made, the gobe, the distal edge is made with a smooth ivory by foot, the beginning is made at the level of the distal end of the plates. On the maximum part, a chasque is made on the pedestal of the lathe of the latetal stanza and the chanting stanza. legs, which increases the anatomy due to the possibility of sleeping a large branch of the poor bone, which will be additionally hold the leg and help ensure its stable fixation.

The lateral, medial, dorsal and anterolateral sides are made rough, and the roughness value, expressed through the parameter Pa, is 0.01-0.2 of the average size of the porous plates. This design ensures both stable primary and secondary fixation, as well as anatomicality, as it corresponds to the sizes of the osteons. Between the dorsal and anterior sides in the proximal part above the porous plates there is a through hole, the axis of which intersects the axis of the leg and is perpendicular to it, and is also parallel to the lateral and medial faces. The opening is used when removing the leg from the femur during revisions and, in the case of the above-mentioned signs, ensures anatomicality with low requirements for surgical accuracy, and also promotes its overgrowth with spongy bone tissue.

The angle of inclination of the neck axis to the leg axis is 131-134°, mainly 132°, which, given the anatomical nature, ensures the absence of loosening during walking, and, consequently, stability fixation. A spherical socket is made on the third side of the pedicle, the axis of which coincides with the axis of the pedicle, and the radius is greater than or equal to the diameter of the cross-sectional opening between the dorsal and arterial sides, and the diameter of the socket cross-section on The anthene joint is at least 2/3 of the thickness of the leg in this plane. The hole is used for clear orientation of the instrument when placing the leg in the thigh and thus ensures stable fixation, anatomicality and ease of placement.

The skin is made of titanium alloys, mainly from bathed alpha + beta alloys, which ensures good safety bios-compatible elasticity of the physical tissue, similar to the elasticity of the physical tissue, i.e. anatomical and stable fixation.

The outer surface of the leg in the distal and proximal part is made with a dielectric coating consisting mainly of compounds of alloy components with oxygen and carbon and not containing compounds of the said components with hydrogen and nitrogen. Such performance by the executive contributes to the achievement of a positive effect both due to the optimal distribution of biopotentials and the use of superficial effects.

The essence of the claimed invention is explained by the drawings, where Fig. 1 shows the leg in the lateral plane (1 - rod, 2 necks, 3 - conical trunnion for seating the head, 4 - porous plates, 5 - lateral edge, 6 - medial edge, 7 - anterior edge, 8 - dorsal edge, 9 - distal part, 10 - proximal part, 11 - curved chamfers, 12 - terannular side, 13 ridge, 14 - through hole, 15 - spherical socket, alpha - angle between the axis of the rod and the axis of the neck, alpha2 - angle of inclination of the lateral edges of the section of the rod, 2alpha3 - angle of convergence lateral and medial faces). Fig. 2 - shows the leg from the side of the lateral facet (2alpha4 - the angle of convergence of the dorsal and anterolateral sides). Figure 3 shows the profile of the pore plate in the variant with a ribbed outer surface at a scale of 100:1 (Ы is the ribbed height, ЙЊ is the ribbed pitch, Ωη\ is the average ribbed size, and a is the gap at the junction of the leg recess with the pore plate). Figure 4 shows a porous plate in section at a scale of 1000:1 (1 - inner surface of the plate, 2 - coating of antimicrobial preparation, 3 - thin film coating on the outer surface of the plate). Fig. 5 shows the profile of the surface area of the lateral face of the leg on a scale of 100:1 (Pa is the roughness parameter - the average value of the height of irregularities within the selected base).

The casing of cementless endothesis of the pelvic joint (Fig. 1) consists of rod 1, οτκοτορο Use neck 2 with camshaft 3 to seat the head. The stem of the leg, at least in the distal part 9, has the form of an equal femoral tapering formed by four faces: lateral 5, medial 6, anteroposterior 7 and dorsal 8. In the proximal part 10, the stems 1 are permanently installed in the notches on the anteroposterior 7 and on the dorsal 8 edges there are two flat plates 4 made of porous bioinert material, the thickness of which is greater than the depth of the excavations by at least the value of the average size of the pit (Fig. 3) and is 20-200 average sizes of the pit. In the proximal part 10 of the rod 1 smooth curvilinear chamfers 1 1 are made to the dorsal 8 and anterior 7 edges. The size of the chamfers increases towards the neck. Additionally and symmetrically chamfers 1 1 are made on the neck 2 from the trochanter side. The bevel angle of the lateral 5 and medial 6 facets 2alpha3 is greater than the bevel angle of the anterior 7 and dorsal 8 facets 2alpha4 (Fig. 2). 10

The angle of inclination of the lateral sides of the trapezoidal cross-section of rod 1 alpha (section A-A in Fig. 1) is 1-10°, mainly 2°. The radii of rounding of the edges of the cross-section at least in the distal part do not exceed 2 mm, mainly 1 mm. The beginning of chamfer 11 corresponds to the beginning of the curvilinear section on the medial side 6.

The bevel angle of the lateral and medial faces of 2alpha is 4-8°, mainly 5.5-6.5°. The bevel angle of the dorsal and anterior faces of 2alpha ₄ is 1-4°, mainly 1.5-2.0°. The bevel angle of the lateral and medial faces 2alpha is greater than the bevel angle of the dorsal and anterior faces 2alpha by at least 2-6°, mainly by 4-4.5°.

Porous plates 4 are located in the area of intersection of neck 2 and rod axis 1 (Fig. 1). The distal edge of the porous plates 4 is located above the beginning of the curvilinear section on the medial facet 6, and the area of the porous plates is at least half the area of the proximal part 10 of the dorsal 8 and anterior 7 facets. The external information of the plates is additionally made of material (fig.3), especially the step Ι _{ and the height η, material are 10-20 centimeters πορ ϋП|. The gap at the junction of the notch with the sharp plate 4, its contour (a) is less than half the size of the square Οπ^. The porous plates 4 can be made (Fig. 4) with a coating 2 on the surface 1 of a gel-like or sublimated antimicrobial preparation, the volume of which is at least 60% filled with the said preparation, and the outer The surface of the plates is made with a thin-film biocompatible, air-tight and easily soluble in biological liquids non-toxic coating.

In the proximal part on the lateral edge 5 (Fig. 1) a ridge 3 is made, the distal edge of which is made with a smooth 1 1

linear path, the beginning of which is made at the outside of the distal point of plates 4. The maximal part is made with a chamfer (Fig. 1) on the foot of the goblin 3 of the late 5th side of the anthene. 12 legs. The lateral 5, medial 6, dorsal 8 and anterior 7 facets are made rough (Fig. 5), and the roughness value, expressed through the parameter P, is 0.01-0.2 of the average size of the porous plates 4.

Between the dorsal 8 and anterior 7 facets in the proximal part 10 above the porous plates 4 a through hole 14 is made, the axis of which intersects the axis of the leg and is perpendicular to it, and is also parallel to the lateral 5 and medial 6 facets.

The angle of inclination of the neck axis to the alpha-ι leg axis is 131 - 134°, mainly 132°. On the anthene base 12 legs, a special hole 15 is made, the axis coincides with the axis of the leg, and The radius is greater than or equal to the diameter of 14, especially the diameter of the cross-section of the hole on the antique table 12 is at least 2/3 thickness legs in this part. The stem of cementless hip endothesis is used together with the cup (full endothesis) or with the modular head (hip endothesis) as follows. By performing asisosis of the soft tissues in the area of the pelvic joint, the head and neck of the femur are removed. In the medullary canal we use a ashpil to imitate the bed under the leg.

The stem is hammered in to a pre-planned depth. The head is placed on the trunnion of the neck. The prosthesis is inserted. The wound is sutured layer by layer and, if necessary, a drainage system is installed.

The use of cementless stem of endoprothesic hip joint of the claimed construction in orthopedics and 12

traumatology allows to ensure equally reliable primary and secondary fixation, stability, anatomicality, low requirements for the accuracy of placement, as well as high adhesion of the entire surface of the leg to the bone tissue, Osteointegration of greater consciousness and, as a consequence, increase the functioning of the synthesis, reduce the rehabilitation of the patient, expand the indications for use.

13

Sources of fame

1. Leg of uncemented endothesis of the pelvic joint of the knee joint, π. SSHΑ Ν° 4728334, 1988;

2. Leg of uncemented endoπροτosis of the pelvic joint of the ΒπzyuΙ Muerz system, z. ΦΡГ Ν° 3822154;

3. Leg of uncemented endothesis of the pelvic joint of the knee joint. Switzerland No. 642252, 1984.

Claims

14 ΦΟΡΜULΑ IZΟΡΕΤΕΗIYA 1. Cementless endothesis of the pelvic joint, made in the form of a leg suture, which swells uncomfortably At the distal end of the stud there is a neck with a conical tsapohoy, os the neck forms an obtuse angle with the axis of the shaft, and the medial edge in the proximal part has a smooth curvilinear transition to the neck, differing in that the cross-section of the shaft at least in the distal part has the form of an equal-femoral tapering, the smaller base of which is located on the medial edges, and the largest one is on the lateral, and the angle of the chamfer of the lateral and medial edges is greater than the angle of the chamfer of the dorsal and anterior edges, in the apical part on the medial edge smooth curvilinear chamfers are made on both the dorsal and anterior edges, the size of which increases towards the neck, on the dorsal and anterior edges in the proximal part there are notches of constant depth, in which flat plates of porous bioinert material are permanently installed, the thickness of which is greater than the depth of the notches by at least the value of the average size, and amounts to 20-200 units of space. 2. Leg of endosis of the pelvic joint πο π.1, characterized by the angle of inclination of the sides The apeceoidal hepatic section is 1 -10°, most importantly 2°. 3. The endoscopic hip joint pedicle according to item 1, characterized by the fact that the radii of rounding of the cross-sectional edges at least in the distal part do not exceed 2 mm, mainly 1 mm. 4. The endoscopic hip joint fusion procedure according to item 1 is distinguished by the fact that the beginning of the chamfers corresponds to the beginning of the curvilinear section on the medial facet. 15 5. The endoscopic hip joint fusion according to item 1, characterized by the fact that symmetrical curvilinear shoulders of increasing size are additionally performed on the neck from the trochanter side. 6. Leg > endothesis of the hip joint according to item 1, characterized by the fact that the angle of the lateral and medial edges is 4-8°, mainly 5.5-6.5°. 7. Leg of endosis of the pelvic joint πο π.1, characterized by the angle of compliance to the salivary and the antenatal area is 1 -3°, most importantly 1.5-2°. 8. The endopathic procedure of the hip joint according to item 1, characterized in that the angle of taper of the lateral and medial faces is greater than the angle of taper of the dorsal and anterior faces by at least 2-6°, mainly by 4.0-4.5°. 9. The endoscopic hip joint fusion according to item 1, characterized in that the porous plates are placed in the area of intersection of the neck axis and the leg axis. 10. The endoscopic hip joint pedicle according to item 1, which differs in that the distal edge of the porous plates is located above the beginning of the proximal portion on the medial edge. 1 1 . The endoscopic hip joint procedure according to item 1, characterized in that the area of the porous plates is not less than half the area of the proximal part of the dorsal or anterior granules. 12. Leg of endosis of the pelvic joint πο π.1, characterized by the external nature of the pelvis The plates are made of additional material, especially the pitch and height of the plates are 10-20 square meters. 16 13. Leg endosis of the hip joint πο π.1, distinguished by the fact that there is a gap at the junction of the notch with the cyst The plate's contour is less than half the size of the previous one. 14. Pelvic joint endosis patina p.1, characterized in that the pure plates are made with Testing on the internal substance of a gel-like or sublimated antimicrobial substance, and the volume πορ, πο smaller than 60% filled with the specified drug. 15. The endoscopic hip joint graft according to item 14, characterized in that the outer surface of the plates is made with a thin-film biocompatible, air-hermetic and easily soluble in biological fluids, non-toxic coating. 16. Leg of endosis of the pelvic joint πο π.1, characterized by the fact that in the maximal part on the latetal hip the goeben is made, the distal edge of the gobe is made with a smooth linear pedestal, the beginning of the edge is made at the outside distal How many plates? 17. Leg endosis of the pelvic joint πο π.1, characterized by the fact that on the maximal part there is a mask on The story is about the location of the latetal leg in relation to the anterior wall of the leg. 18. Leg of endosis of the pelvic joint πο π.1, distinguished by the fact that it is latetal, medial, dorsal and antenatal. made by shearing, especially the value of sheariness, expressed through the pattern, is 0.01 -0.2 πορ Plate plates. 19. The endoscopic hip joint fusion according to item 1, characterized by the fact that a through-hole is made between the dorsal and arterial faces in the proximal part above the porous plates A98/0003 17 An opening whose axis intersects the axis of the pedicle and is perpendicular to it, and is also parallel to the lateral and medial faces. 20. Leg endosis of the pelvic joint πο π.1, characterized by the angle of inclination of the cervical axis to the axis of the leg is 131 -134°, most importantly 132°. 21 . Leg of endosis of the pelvic joint πο π.1, distinguished by the fact that there is a leg on the antheneous side a spheroidal hole is made, the axis coincides with the axis of the leg, and the radius is greater than or equal to the diameter of the liver News between pre-seal and athethetic joints, especially the diameter of the cross-section of the hole on the anthenic side is not less than 2/3 of the thickness legs in this plane. 22. Leg endosis of the pelvic joint πο π.1, distinguished by the fact that it is made of titanium alloys, Mostly from forged alpha + beta alloys. 23. The endoscopic hip joint pedicle according to item 1, characterized in that the outer surface in the distal and proximal part is made with a dielectric coating consisting mainly of compounds of alloy components with oxygen and carbon and not containing compounds of the specified components with hydrogen and nitrogen.