Oscobal Ag

Osteo Ag

Heinz Mittelmeier

Beat Leu

Heinz Moser

Peter Ries

Frank Baumgart

Bernhard Mittelmeier

Otmar Schmitt

The metal wire structure for endoprosthetics is formed of a sintered hollow mesh knitting of elastic metal wires (D), said knitting being preferably manufactured in the manner of a 'rete milanese'. Said metal wire structure is either used as a coating (1) of an endoprosthesis (3) or, after having been sintered together, as a bone replacement piece. Such a metal wire structure allows to obtain a good anchorage in the bone, since the pore size of said meshes may be adapted to the local conditions, on one hand, and on the other hand, the remaining elasticity of said meshes allows a suitable transition from said prosthesis to the bone.

Metal wire structure for endoprosthetics

A bone cement exhibiting superior mechanical strength and body compatibility, as well as shortened polymerization time and reduced peak polymerization temperature, includes a conventional polymethyl methacrylate bone cement to which has been added up to about 4% by weight of carbon fibers and from about 1 to about 30% by weight of the mineral components of natural bone tissue (apatite).

Reinforced bone cement

The apparatus for electrical stimulation is more particularly adapted for the treatment of scoliosis and comprises an electrical circuit which delivers individual pulses having a duration of about 1 ms, an amplitude of about 150 V, a constant current intensity of about 75 mA and a frequency of 100 Hz as well as series of pulses with rising amplitude and a ramp up phase of about 2 s, followed by holding phase of about 2 s and a time off between two series of pulses of about 10 s. The apparatus further comprises three channels, whereby the first channel is applied on the side of the curvature, the second channel on the side of the counter curvature and the third channel on the abdominal musculature, whereby all channels are fed simultaneously.

Method for electrical stimulation, more particularly for the treatment

The bone substitute material on the base of natural bone is rendered completely free of albumin and antigen by premaceration, pyrolization and sintering and its frame work consists of only the natural mineral structure of the natural bone. In the process of production of this bone substitute material the bone pieces are submitted to a pretreatment with warm water for removing of the soft parts, subsequently takes place a dealbumination by means of a solution of 10 to 30% H.sub.2 O.sub.2 in a shaking machine and a degreasing with ether. The bone pieces treated in this way are subsequently submitted to a combustion in a stove at 400.degree. C. to 1500.degree. C. and then to a sintering. This bone substitute material which may exist in the shape of the bone part to be replaced forms a form stable matrix for the bone regeneration in which only pure 'mineral bone' is present so that no immunogen reactions can take place. The process which includes combustion and sintering is considerably shorter than known processes.

Bone substitute material on the base of natural bones

For producing the bone substitute material from collagen and hydroxyapatite, an aqueous solution of cleaned collagen is mixed with a cross-linking agent causing only a partial cross-linking, and the mixture is lyophilized. The quantity of the cross-linking agent is chosen such that the collagen retains its resorbability and its absorptivity vis-a-vis bodily fluids, the material further showing no undesirable side effects. Preferably less than 1% by weight of formaldehyde, one of the preferred cross-linking agents, is added, with reference to the dry weight of collagen, and sintered apatite grains with a diameter of 50-300 .mu.m are used. Such a bone substitute material is stronger and less tearable as previously known materials and insures a good promotion of the growth of own bone tissue and the substitution by it.

Method of producing a bone substitute material

A bone substitute comprised of collagen material in the form of fleece or a spatial meshwork having apatite, the mineral component of bone material, admixed therewith. The structure of the collagen material may be strengthened by carbohydrate or starch or may be applied, in the form of a coating, to a honeycomb-like basic structure made from a variety of materials. Such a bone substitute has a good support quality, promotes bone growth and also has a good styptic or haemostatic effect.

Bone substitute and a method of production thereof

A slide prosthesis for the knee joint is provided to be secured free of cement, the tibia members, the femur members and the surface replacement for the knee cap having anchoring pins which are provided with a saw tooth-like or bone screw-shaped profile. The tibia and knee cap members are preferably made of carbon fibre-reinforced plastics material and the femur members of aluminium oxide ceramic material. In order to assist growth of the bone to the prosthesis members, the members are coated at the corresponding points with bio-active particles, such as apatite-containing glasses, apatite particles or dealbumined bone material.

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Homburg-Schwarzenbach, Germany

Heinz Mittelmeier