A carbon implant of the hip

Abstract

Purpose. To substantiate the strength properties and wear resistance of the hip implant made of carbon material. Materials and Methods. We have developed a construct of the hip carbon implant; picked and used the durable biocompatible carbon material during the implant making; studied and presented the properties of the materials being used. The implant consists of a stem, a cup and a head. We mounted all the details as a unified medical product in a free condition during surgery. The implant stem is made of carbon plastic and firmly fixed in femur by cementless fitting. The implant head is made of firm fine-grained graphite of MPG-7 trademark, and it is attached to the stem by cone fitting. The implant cup is made of MPG-7 graphite and fit into the acetabulum with cement. We used slide fitting to attach the cup to the head. Results. The friction coefficient for graphite-graphite shown to be 0.1, erosive wear within 20 hours of uninterrupted abrasion with 100-kg load (weight of a person) to be 0.453×10-9 m/m, thereby allowing to suggest the product wear resistance for one hundred years. Conclusion. The material proposed for implantation is highly biocompatible, non-toxic, it doesn’t change under the influence of biological environments, is not subjected to corrosion when contacting with living tissue, as well as it is characterized by the lack of fatigue stresses, the low friction coefficient and wear amount, the potential to stimulate the growth of biological tissue. None of the currently used implanted materials possesses such a set of properties.