Introduction: There is still a discussion whether cementless hip cup revisions should be performed with a press fit cup or a threaded ring implant.
Materials and methods: The results of 58 hip cup changes using the spherical, threaded ring "Munich" are presented. In 16 cases, the ring "Munich I" with a smooth surface and in 42 cases the ring "Munich II" with a corundum-blasted surface were implanted. Mean follow-up was 7.5 years; radiological signs of loosening and the Harris Hip Score were examined.
Results: The re-revision rate for aseptic loosening of the ring was 12/58 overall (Munich I: 5/16, Munich II: 7/42). The average Harris Hip Score was 76.2 overall (Munich I: 74.4, Munich II: 76.8). Higher survival rates were achieved with the "Munich II" ring due to improved construction details.
Conclusion: These rates are still below those reported for press-fit cups, the technique described by Slooff or reinforcement rings.