IMPLANT FOR METAPHYSEAL FIXATION OF THE TIBIAL COMPONENT OF THE KNEE JOINT ENDOPROSTHESIS AND A HOLDER FOR ITS INSTALLATION Russian patent published in 2022 - IPC A61F2/38 A61F2/46 

FIELD: medicine.

SUBSTANCE: group of inventions relates to the field of medicine, namely traumatology and orthopedics, and is used in primary or revision endoprosthetics in patients with bone marginal and central metaphyseal defects in the implantation zone. An implant is proposed for metaphyseal fixation of the tibial component of the knee joint endoprosthesis in the form of a hollow truncated cone, having an upper edge of a larger diameter than the lower edge of a smaller diameter, with a central hole for the rod of the tibial component of the endoprosthesis, with a wall of porous metal. From the upper edge of the hollow truncated cone, cutouts extend downwards to interact with the projection of the tibial component plateau. The inner surface of the hollow truncated cone has projections. The implant wall is made of porous titanium nickelide (NiTi). On the inner side surface of the hollow truncated cone, along one diametrical line passing through the central axis at an equal distance between the cutouts, at the level of the lower edge of the cutouts, there are recesses for interaction with the balls of the working part of the holder. On the inner lateral surface, the hollow truncated cone has sections with stepped projections: the upper sections start from the upper edge of the larger diameter of the hollow truncated cone, the stepped projections of the upper sections have a length equal to the distance between the cutouts and end above the edge of the recesses at a distance of 1/10 of the height of the implant, the lower section is located below the edge of the recesses at a distance of 1/10 of the height of the implant and it reaches the lower edge of the smaller diameter of the hollow truncated cone, has circular stepped projections. The diameter of the circular stepped projections gradually decreases in the direction from the upper edge of the larger diameter of the hollow truncated cone to the lower edge of the smaller diameter. The verges of the edges of the hollow truncated cone are rounded. The holder for the installation of the above implant includes a handle and a lower working part. The working part has the shape of a truncated cone, immersed in the implant in the form of a hollow truncated cone. On the side of the larger base of the truncated cone of the holder, there is a circular limiter with a diameter exceeding the diameter of the larger base of the truncated cone and a rod. A central cylindrical hole passes through a truncated cone, a circular limiter and a rod. Between the central cylindrical hole and the side wall of the truncated cone there are blind channels with rolled exit holes on the outer side surface of the wall of the truncated cone. The blind channels are located perpendicular to the longitudinal axis of the holder, oppositely along one diametrical line located between the projections on the outer side surface of the truncated cone. The projections on the outer side surface of the truncated cone are located under a circular limiter, correspond in shape, size and location to the cutouts of the implant. The blind channels have fixation elements in the form of springs acting on the balls with the possibility of their partial exit from the rolled holes of the blind channels to interact with the recesses on the inner side surface of the implant. In the central part of the rod, riffling is performed on the outer side surface, a rectangular through hole is located at the opposite end of the rod, to which the central cylindrical hole reaches, a circular groove is made for the coupling balls, followed by a square four-sided end of the rod interacting with the coupling. The coupling has an external cylinder with circular ribs on the surface, a thrust ring on the side of the working end of the holder and an internal two-stage cylinder, between which a return spring is installed. The outer cylinder is installed with the possibility of movement along the inner cylinder, which at the first stage from the side of the working end of the holder has a larger outer diameter than at the second stage, which forms a cavity with the outer cylinder for the return spring. A through hole passes through the inner cylinder, having from the working end a section with a cross section in the shape of a square, corresponding in shape to the square tetrahedral end of the rod, on two opposite walls of which cylindrical holes with an inner annular projection for balls interacting with the circular groove of the rod are made opposite each other when it is installed in the coupling. The section of the through hole with a cross section in the shape of a square turns into a cylindrical section. The second stage of the inner two-stage cylinder of the coupling exits from the outer cylinder of the coupling and has an external thread on this section from the side of the transverse handle, for interaction with it. The transverse handle on the working side has a cylindrical hole with a thread in the lower part in the center for connection to the section of the second stage of the two-stage cylinder of the coupling with an external thread coming out of the coupling. In the upper part, in the center of the transverse handle, there is a first round impact pad with an entrance hole into a cylindrical inner cavity for installing a rod-shaped handle with upper and lower pads. A movable hammer in the form of a dumbbell is placed on the handle rod. A cylindrical thickening is made on the handle rod in front of the lower platform. The lower platform has the shape of a rectangular parallelepiped with a length different from the width, with rounded ends, with a central through cylindrical hole connecting the rounded ends of the parallelepiped. On the edges of the central through hole there are balls protruding from the rolled holes, between which a spring with the possibility of partial stroke is installed. The rounded ends of the parallelepiped of the lower handle pad have a width equal to the diameter of the cylindrical thickening of the handle. The balls from the rolled holes interact with the support slots on the side surface of the cylindrical inner cavity of the transverse handle. The cylindrical inner cavity has a diameter equal to the length of the parallelepiped at the level of the central through hole, a height equal to the height of the parallelepiped. The cylindrical inner cavity has on the inner side surface two support slots located along one diametrical line in the direction of the central longitudinal axis of the transverse handle for interaction with balls placed in rolled holes on the rounded ends of the parallelepiped of the lower handle pad when it is rotated 90°. The inlet to the cylindrical inner cavity and the inner cavity are connected to the lateral surface of the transverse handle by a cutout having a width equal to the diameter of the cylindrical thickening of the handle and a height equal to the total height of the cylindrical thickening of the handle and the height of the cylindrical inner cavity. The surface of the transverse handle, except for the first round impact pad, is covered with heat-resistant rubber.

EFFECT: inventions make it possible to securely and stably fix the implant on the holder, achieve the correct location during installation, without limiting visual control, reduce the time and cost of the operation and simplify it as a whole.

8 cl, 21 dwg, 1 ex