[The Balgrist hip cup--a 4-to-10-year survival analysis of cement-free hip cups].

The results of 715 cement-free acetabular sockets used in primary total hip arthroplasties are shown according to a survivorship analysis after Kaplan-Meier. The survival probability of the examined cement-free polyethylene sockets after 5 years lies between 88.1% and 93.6% (Endler screw socket of polyethylene: 93.6%; Balgrist socket of polyethylene: 88.1%; Balgrist socket of polyethylene with titanium coating: 90.6%). The survival probability of the Endler socket after ten years is only 44.2%. No statistically significant difference in the survival curves of the polyethylene socket models could be found (p logrank 0.797). The Balgrist sockets with the outer split ring made of titanium show a far better survival rate (98.8% after 4 years) than those made of polyethylene. This result justified the further development of a Modular Revision socket made of titanium so that the original idea could be extended to revision interventions where large acetabular defects have to be coped with.