FEMUR HEAD-SEGMENT PROSTHESIS AND INSTRUMENT FOR PRECISE INSERTION OF A SEGMENT PROSTHESIS

摘要

The invention relates to a method in which a cartilaginous, osseous or osteocartlaginous lesion in the region of a joint surface of a femur head is repaired by inserting a modularly constructed segment prosthesis (ball segment-, ball segment-prosthesis). The segment prosthesis comprises a carrier component, a prosthesis calvaria and a conical corrective ring system which is placed between the prosthesis calvaria and the support components for the precise vertical and angular positioning of the prosthesis calvaria relative to the carrier components used. Conical insertable-connections located between individual prosthesis components create a modular prosthesis system. The carrier components are produced in two different embodiments: one is suitable for uncemented implantation by radial clamping and/or screwing of the prosthetic component into the bone and the other one is suitable for cemented implantation. The prosthesis calvaria has an opening angle of between 90 DEG and 120 DEG and is produced with a diameter between 38 mm and 60 mm. Alternatively, a prosthesis calvaria with an altered design can be used as a carrier for the direct in vitro culturing of cartilage cell or tissue layers. It has been shown that precise implantation of the prosthesis components increases the life-time of the prosthesis and reduces the incidence of secondary arthritic alterations on the acetabular side. To this end, a guide instrument which can be positionally fixed in the region of the lesion is used. Said guide instrument has a pliers-shape with a ring-shaped opening located on the side of the defect and centered at the opposite side of the defect to enable precise axis-aligned guidance of grinding-, cutting- and insertion instruments.