GB1444724A - Endoprosthetic joint - Google Patents

Abstract

1444724 Endoprosthetic joints HOWMEDICA INTERNATIONAL Inc 26 Sept 1973 [15 Sept 1972] 42950/72 Heading A5R A surgical device for use between two or three bones of a joint, comprises a first location member in the foam of a bobbin 6 having in its cylindrical periphery a square section channel-shaped groove 7 constituting an engagement portion, a securing element in the form of a screw 13, and an engagement member 10 having an engagement surface 11 engaging the groove 7, the natural tendons and muscles of the patient being relied upon to hold the engagement surface on the engagement member in the groove of the location member in use. The screw 13 fits into a hole 8, inclined to the longitudinal axis of the bobbin with one end 9 of the hole aligned with the said axis. The engagement member 10 is part angular and is of a width such that it fits within the groove 7, the surface 11 contacting the bottom of the said groove and the engagement member and thereby being rotatable about the axis of the bobbin but being held against axial movement. The outer periphery of the engagement member is provided with projections (12) Fig. 4 (not shown) which assist in securing the engagement member in position on a bone 3. For use between three bones, the screw 13 carries a second location member 14, which is also in the form of a bobbin, having an arcuate groove 15 in its cylindrical periphery. The screw passes through a hole 16 similar to the hole 8. A second engagement member 18 cooperates with the member 14 and has a part-spherical upper end 19, the lower part being in the form of a spigot 20. The partspherical portion 19 engages the semi-circular groove 15 such that the member 19 can rotate in the groove and also move angularly around it. The device is fitted into the bones by cutting a slot 21 in the lower end of a bone 1 thus leaving two straight side portions 22, 23. The slot is angled as a whole in relation, to the longitudinal line 25 of the said bone.