IMPLANTATION METHOD AND ENDOPROSTHESIS TO APPLY THIS IMPLANTATION

Abstract: The implantation method consists in the successive introduction of multilateral needle salients into the spongy bone whilst the needle salients are symmetrically placed on the terminal surfaces of the endoprosthesis, up to the resistance with its edge and the resistance surface, whilst the remaining free area between the needle salients is filled up to the terminal surfaces in the "biological silence" by osteoblasts. The endoprosthesis distinguishes itself by the fact that it is composed by the glenoid cavity (1) and the head (2) which have round terminal surfaces (3 and 11) with multilateral needle salients (4) which are placed on them (1, 2) with a different length and mutually parallel axes which are perpendicular to the planes in which lies the round resistance edge (6) of the glenoid cavity as well as the resistance plane (10) of the head.

Description: IMPLANTATION METHOD and endoprothesis to apply this implantation. Subject of this invention is the implantation method as well as the endoprothesis to apply this method in the bones' surgery,without using surgical cement. In the known implantation methods the connection between the endoprothesis and the bone takes place by the growing into pores of proper dimensions,into indentations and other irregularities on the surface of the endoprothesis. fixed on the spot where it is mounted with the help of surgical cement, or mecanically. In order to complete losses of long bones' shanks among others there are used endoprothesis joined with the bone by sphenoiding into the marrow cavity, using surgical cement, like for instance polymethacryl methyl, with the help of roughly rolled threads. This joining method is possible when using metalic endoprothesis, which however, have the imperfection that there is a very small surface comprised by the in-growing of the spongy bone. Besides, the joining of the endoprothesis to the bone by surgical cement has some defects. The main defect is, that whilst getting old the material weakens and causes its bursting and in consequence of irritation it causes a separation from the bone and this, in turn, causes a loosening of the endoprothesis and the bone ' s atrophy. Thanks to the description of the patent DE3443109A1 there is also known a solution in which the prothetic implants have more secure fastenings by applying conic irregularities which are sticking out of the terminal surface of the endoprothesis and which are directed against the joining surface of the bone. The conic irregularities are pressed into the spongy bone and cause an increase of the contact surface which is favorable to the fixation, thanks to the growing in. An imperfection of this solution is the fact that there is no possibility to increase in an optimal way the contact surface of the endoprothesis with the bone because the conic irregularities are placed on a plane surface in distances.However, the plane contact surface because of it's shape renders impossible the growing of the spongy bone in a shape similar to the natural form.which would assure a good amortisation of the joint's charge. The aim of the invention is the elimination of these imperfections by creating an implantation method of the endoprothesis, thanks to which there would take place a simple and durable union with the bone tissue with the cortex as well as with the spongy tissue, ensuring in the same time the possibility to rebuild the regenerated bone in the form similar to the natural and original one. Also another aim of this invention is the creation of an endoprothesis which would make possible the application of this method in the bone surgery. This aim has been achieved thanks to this invention according to which the endroprothesis is implanted by help of salients of the terminal surface in the spongy bone, at first by the central salient and then by the extreme salients in such a way that the terminal surface enables by its form to the growing in osteoblasts to reshape the bone in the external form similar to the natural one. The implantation method of the endoprothesis is realized according to the invention by removing the defective tissue from the bones which enter into the union which creates the joint and to give them the form similar to the configuration designated by the peaks of the multilateral needle salients, which are introduced into the spongy bones, by and by, maintaining the endoprothesis in a central axis of the operated glenoid cavity of the bone as well as the operated bone head. Simultaneously along the axis of the bone's head there is introduced a central needle of the endoprothesis 's head into the spongy bone in order to assure to its resistence surface a contact to the periosteum, to the cortex and to the adjacent spongy structure lamella, in which are introduced needle salients lying in a distance greater than the plane of the resistence surface, and the distance between the remaining needle salients which have not been introduced into the spongy bone until the terminal surface is filled up in "biological silence " ' by osteoblasts. The glenoid cavity of the endoprothesis is implanted according to the method of this invention so, that the resistence edge lies on the bone perpendicularily to the central axle of the acetabulum of the bone. The resistence edge is placed symetrically with regard to the axle. The needle salients which are near the spherical belt on the terminal surface of the endoprothesis are simultaneously partially introduced into the spongy structure of the bone. The remaining surface between the multilateral needle salients which are not introduced into the spongy bone down to the terminal surface are filled by osteoblasts in "biological silence". The endoprothesis to be applied according to the method of the invention is composed of the acetabulum and the head which on their terminal surfaces have on the rounded multilateral needle salients with parallel axles and different length, the whole surface of which makes the multiplicity of the joint's surface whilst the edges of the basis of neighbour needles adjoin to each other and their axles are adequately perpendicular to the surface in which lies the resisting edge of the acetabulum as well as the resisting surface of the head. An example of an endoprothesis joint according to the invention is given on the enclosed design where figure 1 shows schematically the acetabulum of the endoprothesis in an axle section and figure 2 shows schematically the endoprothesis ' s head in an axle section. The joint's endoprothesis is composed by the acetabulum (1 ) and the head (2). The acetabulum (1) has an external spherical terminal surface (3) which is equipped with multilateral needle salients (4) with axles parallel to each other and each one is parallel to the central axle of the acetabulum and the circular surface (5) determined by the resistence edge (6) parallel to the central axle of the 80 acetabulum. The multilateral needle salients (4) have common basis edges (not shown on the design) with neighbour needle salients (4) and a different length. The length of the multilateral needle salients (4) measured from the base on the terminal surface (3) is determined together by the central and the terminal surface (3), the theoretical spherical surface (7) which crosses the tops of a part of the 85 multilateral salients (4) as well as the plane in which lies the surface (5). The extreme external multilateral needle salients (4) do not exceed the tangent to the terminal surface (3) which in the same time is parallel to the axle of the acetabulum and those salients which lie close to the resistence edge (6) have the least length. 90 The acetabulum (1) is equipped with a pan (8) to place the head (2) which constitutes a section of the sphere with the external surface (9) and has a ring resistence surface (10) and a spheric terminal surface (11). On the spheric terminal surface (1 1) there are multilateral needle salients (12) and a central multilateral needle (13) with parallel axles to each other whilst the multilateral central needle 95 covers the axle of the head (2). The multilateral needle salients (12) have common edges of the base (are not shown on the design) with the neighbouring multilateral salients (12) and a different length. The multilateral extreme needle salients (12) which are situated close to the 100 resistence surface (10) have an advantageous relation to one half of the base diagonal up to the height 1:5, instead the blade of the multilateral central needle (13) lies on the big circumference of the ball which creates the surface (9). The remaining lengthes of the multilateral needle salients (12) are determined by the distance between their base on the terminal surface (1 1) and the blades which lie 105 on the theoretical surface of the bowls (14) with a radius which is equal to the distance between the axle of the multilateral needle salient (12) and the axle of the multilateral central needle (13) carried out from the point which lies between the axles on the straight which connects the tops of the multilateral opposite extreme salients (12). The surfaces of the multilateral needle salients (12) and the surfaces of the multilateral central needle (13) have a total surface seven times bigger than the surface (9). This reflects approximately the internal surface of the essential of the bone bark on which the head is implanted. Simultaneously the different length of symetrically placed multilateral needle salients (12) causes their steady and successive introduction into the spongy bone. The resistence edge (6) as well as the resistence surface (10) lean properly on the bone of the pelvis acetabulum and on the bark edge of the bone tigh neck. The needles' composition increases considerably the adhesion when leaning on the spongy bone construction and this causes a more effective amortisation of the charge and moreover, it increases the fixation power in the bone tissue preventing thus the endoprothesis from spraining and loosening. The endoprothesis is produced in various dimensions properly fixed according to the gradation of biological sizes and from non-toxic materials corresponding biologically and possessing the proper mechanical properties. The acetabulum as well as the head, among others, can be produced entirely out of plastics with a varying density gradation so that its resistence power would be a function of the varying spring energy of the plastic, decreasing in due measure, as it removes from the surface in both parts of the endoprothesis. thanks to what in the mass there is obtained in an almost natural way a suppression of the power activities which occur in the joints' system. One of the advantages of the endoprothesis is the proper arrangement of power between the bone and the endoprothesis. Moreover, the operation connected with the implantation is simplified and can be applied with sick people in a considerably wider age range. 135 Another advantage is the longer durability of the endoprothesis and if necessary, it is easy to exchange whilst the endoprothesis in its shape is always very close to the biological model. In the same time the endoprothesis facilitates its application with patients with a big osteoporosis and enables the implantation without using surgical cement. 140 Also it should be underlined that the endoprothesis implantation according to this invention causes less injuries of the bone tissues. The method of implantation as well as the endoprothesis in biologically verified dimensions according to this invention can be applied in operations of bone surgery on all spherical joints which occur with people and animals and especially 145 with implantations of hip joints, elbow joints, knee joints, shoulder joints, ankle bone joints, hand and foot joints as well as with implantations of inter-vertebra discs. The subject of this invention can be applied also in all other cases of similar biomechanical properties.

Claims: CLAIMS 1. The method for endoprothesis implantation by sharply ended salients which are placed on the terminal surface is distinctive by the fact that the salients in the form of multilateral needles situated on the round terminal surfaces of the glenoid cavity and of the head are introduced successively and symetrically into the spongy bone up to the resistence of the resistence edge of the glenoid cavity of the endoprothesis with the bone as well as the resistence surface of the endoprothesis head up to the resistence with the essential cortex and the adjacent lamella which has a spongy structure. 2. The method according to the reservation 1 is DISTINCTIVE by the fact, that the space between the multilateral needle salients which are not introduced into the spongy bone up to the terminal surface is filled in "biological silence" by osteoblasts. 3. The endoprothesis of the joint composed by the glenoid cavity and the head which have sharply ended salients on the terminal surface is DISTINCTIVE by the fact, that the terminal surfaces of the glenoid cavity (1 ) and of the head (2) have the shape of a round bowl (3) and (1 1 ) and the sharp salients situated on them with mutually parallel axes have the form of multilateral needles (4) and (12) and (13) with a different length situated symetrically and each one of the salients contacts the neighbour needle salients (4) and (12) which are situated properly close to the resistence edge (6) and close to the resistence surface (10) have the least length, but the total surface of the needle salients (12) and of the central multilateral needle (13) is seven times bigger than the surface (9). 4. The endoprothesis according to the reservation 3 is DISTINCTIVE by the fact, that the resistence edge (6) of the glenoid cavity (1) as well as the resistence surface (10) of the head (2) are situated in parallel planes properly to the axe of the glenoid cavity (1) and to the axe of the head (2) in which is placed the multilateral central needle (13) which has the biggest length.

Inventors: ROGALA PIOTR, ROGALA, PIOTR
Applicants: ROGALA PIOTR, ROGALA, PIOTR
Application year: 1995
Main classification: A61F2
IPC codes: A61F2