Prosthesis for replacement of the hip's joint

A prosthetic device, comprising:

• (a) a cup portion with an outer surface adapted to fit in a cavity formed in a first adjacent bone, the cup including a smooth, at least partially rounded, bearing surface;
• (b) a head connected to a connection means adapted to be fixed to a second adjacent bone, the head being at least partially rounded in shape and sized to fit closely into and engage the bearing surface on the cup;
• (c) the bearing surface including a circumferential reservoir in the vicinity of the outermost portion of the rounded bearing surface which engages the head for collecting synovial fluid which can be drawn by capillary action between the head and bearing surface for lubricating the portions of the bearing surface and head that engage each other;
• (d) the bearing surface being no greater than hemispherical in shape, the reservoir being located adjacent to the outer diametrical plane of the bearing surface;
• and
• (e) protrusion means provided on the bearing surface on the outer end of the reservoir, the protrusion means projecting inwardly a distance sufficient to provide a slight friction lock for maintaining the head in place.