BIARTICULAR HIP ENDOPROSTHESIS WITH SPHERICAL HYDROSTATIC SUPPORT OF HEAD Russian patent published in 2018 - IPC A61F2/32 A61F2/34 A61F2/36 

FIELD: medicine.

SUBSTANCE: biarticular hip endoprosthesis with a spherical hydrostatic support refers to medical technology and can be used in orthopedics and traumatology in the treatment of injuries, diseases and hip joint damages. Biarticular hip endoprosthesis with a spherical hydrostatic head support contains a wedge-shaped leg, a spherical head, an acetabular cup, insert and a tubular conical corrugated elastic sheath reinforced at the ends with large and small rings, respectively. Leg has a protrusion at the proximal end with three sections in the form of truncated cones: the first - for fixing the spherical head, the second transitional and the third threaded, adjacent to the leg. Upper minor base of the third portion is the large base of the second portion, and in the latter the smaller base serves as a large base of the first portion. Acetabular cup is made in the form of two hemispherical sheaths concentrically arranged with a gap and connected to each other along the edges, forming a slit-shaped cavity. Outer hemispherical sheath is elastic. Inner hemispherical sheath has a "waffle" surface on the convex side, and has a conical threaded surface on the side of the concave surface. Radial holes are made in the upper part of the edge. Apertures are also made at the junction of the outer and inner hemispherical sheaths. Insert is made composite and has an upper and a lower part. Upper part is made in the form of a hemispherical sheath with an outer "waffle" surface and having a cylindrical skirt along the edge, the inner and outer surfaces of which are a continuation of the inner and the outer surfaces of the sheath, and in which, with the same circumferential pitch, radial openings are provided for communicating with the radial openings of the inner hemispherical sheath of the acetabular cup. Upper part of the insert is fixed immovably on the inner hemispherical sheath of the acetabular cup. Lower part is made in the form of a sleeve having an inner spherical surface for abutting against the surface of the spherical head, and the outer surface is cylindrical on one side with a protruding collar for fitting its end to the end of the skirt, and, on the other hand, with a conical surface expanding outwardly to abut the second transition portion of the protrusion of the leg, with the possibility of limiting the angle of rotation of the protrusion with the leg. On the cylindrical surface, with a transition to the underside of the collar, grooves are provided with the possibility of communicating with the apertures at the junction of the outer and inner hemispherical sheaths of the acetabular cup. Small ring of said tubular conical corrugated sheath has an inner conical self-sealing thread for hermetically-sealed connecting to the third portion of the leg protrusion. Large ring has an external conical self-sealing thread for hermetically-sealed connecting to the conical threaded surface of the edge of the inner hemispherical sheath of the acetabular cup. Cavity formed by said tubular sheath and communicating with her the surfaces of the protrusion of the leg, insert, and through said holes and grooves with the slit-shaped cavity of the acetabular cup is filled with a bioinert antifriction nano-liquid with the possibility of circulation.

EFFECT: invention provides, firstly, guaranteed availability of lubricant in the gap between the spherical surfaces forming the ball joint of the head and the insert, thus, the exclusion of their direct mechanical contact during the period of maximum static and dynamic (impulse, shock) loads arising during walking, secondly, the creation of a closed zone for the placement and operation of the ball joint "head-insert", which is capable of retaining artificial lubricant and excluding the ingress of its wear products into the human body, thirdly, the conditions for the adaptation of the spherical surface of the acetabular cup to the surface of the cartilaginous layer of the acetabulum, which can increase the area of their contact for the purpose of a more even distribution of the load, and, fourthly, a decrease in the mass of the endoprosthesis to improve the biomechanics of motion.

1 cl, 5 dwg