Abstract: To facilitate the trimming of flange 100 (FIG. 6) of a prosthesis 101 (FIG. 6) to fit closely into reamed out acetabulum 200 in hip bone 201, the aid comprises a body component 11 which corresponds in overall shape to socket member 102 (FIG. 6) of the prosthesis and a separate flange 13 having a protrusion 14 engageable alternatively into socket 12 in the body component 11 and socket 104 of the prothesis. The entire aid is alternately offered into the acetabulum 200 and removed for trimming its flange 13, this being repeated until a good fit of the flange 13 into the acetabulum 200 is achieved. Then, the flange 13, removed from the body component 11, is fitted to the prosthesis 101 (as in FIG. 6) and the flange 100 of the prosthesis can then be trimmed straight away accurately for fitting into the acetabulum 200.

Abstract: An acetabular prosthesis comprises a body 41 of plastics material defining a part-spherical socket cavity 43 surrounded by a rim 44. A flange extends outwardly from the rim 44. At 48 it inclines from the rim 44 in the direction of the body 41 and at 49 it inclines from the rim in a direction away from the body 41, while lobes 46, 47 therebetween are correspondingly curved. This arrangement provides for a considerably increased area of bone in the acetabulum to be available as a cementing surface when the prosthesis is fitted into a reamed out hip acetabulum in the special circumstances of the invention which is that the axis of socket cavity 43 extends substantially transversely with no or little anteversion.

Abstract: An acetabular prosthesis for use in an artificial hip joint. Because acetabula vary in size, it is not practicable to produce a single prosthesis for each acetabulum, being preferable to provide a blank which can be manually trimmed to fit each acetabulum. Here a blank is used in the formation of an acetabular prosthesis comprising a body surrounding and defining a part-spherical socket whose entrance is surrounded by an annular rim and having a flange extending outwardly and rearwardly from the periphery of the rim and made of a material capable of being manually trimmed to be asymmetrical. The flange may be marked with cutting lines to indicate where it should be trimmed to fit a left or right acetabulum.