CS238769B1 - Joint components of joint and bone endoprostheses - Google Patents

Abstract

The solution concerns the connecting components of endoprostheses of joints and bones made of plastics, filled with inorganic fillers, usable for the manufacture of implants for bone and joint operations in orthopedics and traumatology. The connecting components are characterized by the fact that they are made of filled plastics, e.g. polyethylene filled with aluminum oxide, on whose surface at the point of their connection with bone or other tissue are created - e.g. by etching - surface-open cavities with a size of 80 to 120 micrometers. The plastics used contain inorganic fillers in an amount of 3 to 60% by weight. The connecting components are suitable for a more perfect connection of living tissue and the implant without the use of bone cement.

Description

The invention relates to joint components of joint and bone endoprostheses, of plastics filled with inorganic fillers, useful for making implants for bone and joint operations in orthopedics and traumatology.

The current practice uses implants to replace bones and joints of metal alloys, ceramic materials or unfilled plastics, or combinations thereof. The main criteria for use in permanent implantation is the need to ensure perfect compatibility with living tissue and maximum wear resistance, so that implants do not have to be replaced.

Another condition is that in the case of ehemico-physical wear, small corrosive particles of a size and amount which are no longer transportable by the organism are not formed.

Otherwise, the particles accumulate around the joints and bones and cause reactive inflammation that passes to the bone. This causes its softening and the implant is released.

Equally important is the mechanical strength with sufficient flexibility, which should be as close as possible to the character of bone tissue. With an increasing difference in elasticity, there is also an increasing stress at the joint of the implant with the bone - due to mechanical oscillations. The organism is confronted not with the desired tight bonds, but only with a damping interlayer of connective tissue. Again, this condition is a frequent cause of implant loosening.

Ceramic has the strongest connection of bone and implant from the above materials. It is not necessary to use bone cement for fastening and the living tissue for firm bonding uses a large surface of porous ceramics - ingrowth of cells into the depressions of the material. Moreover, this ingrowth is stimulated by the contact of the tissue with the surface-bound ceramics ions. The disadvantage of the ceramics, however, is its low elasticity, which is not commensurate with the original bone.

Other materials mentioned above must be fixed with bone cement. Its use is accompanied by hardening by increasing the temperature up to 80 ° C, which causes thermal damage to living tissue and it is then unable to firmly bond, so it is necessary to use bone tunneling, deep incisions, etc.

These disadvantages eliminate the joints of the arthroplasty of the joints and bones according to the invention, which consists in that the joints are made of plastics filled with inorganic fillers in an amount of 3 to 60% by weight and on the surface of which they are formed tissue to an open depression surface of 80 to 120 microns. Implants made from them meet the conditions of strength and elasticity close to the character of bone tissue, good sliding properties in the places of the movable part of the joints, minimal abrasion and good tolerance by the organism.

Repairing the filled plastic surface is accomplished, for example, by etching or grinding in a portion to be firmly attached to bone or other tissue to form an open cavity surface of 80 to 120 microns allowing tissue to penetrate the filler grains. This fulfills the condition for firm bonding to bone stimulation - as with ceramic implants, so there is no need to use bone cement.

The following are used as filler plastics: ultra-high molecular weight polyethylene, pepper. type Chirulen R, filled up to 60% by weight with micronized limestone, calcined kaolin, bentonite or anhydrite, polypropylene filled up to 60% by weight; aluminum oxide, short glass fibers, talc. Further polyamides such as type FA - 6 - alkamide, filled during polymerization up to 60% of the fillers mentioned above.

Claims (2)

SUBJECT OF THE INVENTION Claims 1. Joint components of joint and bone endoprostheses, characterized in that they are made of filled plastics, eg polyethylene filled with alumina, and are formed on their surface at the point of their connection with bone or other tissue by etching a surface open cavity of 80 to 120 micrometers. 2. Joint components of the joint and bone endoprosthesis according to claim 1, characterized in that the plastics contain inorganic fillers, for example calcined kaolin, micronized limestone, in an amount of 3 to 60% by weight.