This retrospective monocentre study investigates long-term results of the cementless parabolic-shaped HI threaded cup.
678 threaded cups made of titanium were implanted into 641 patients from November 1991 to May 1995. Mean age was 67 years, 65 % female, 35 % male. From December 2005 until October 2006, 165 patients (168 hips) underwent complete clinical and radiological follow-up, data of the remaining group were taken from the files. Using the Kaplan-Meier method, survival rates of the threaded cup were calculated.
For all patients the average survival time of the cup was 14.2 years, the corresponding survival probability was 93 % (+/- 3.7 %) after 14.5 years. For the patients with complete follow-up, average survival time of the cup was 14.0 years, the corresponding survival probability was 93 % (+/- 5.2 %) after 14.5 years.
Our results are comparable to those of threaded cups with a conical design (Zweymüller), the HI threaded cup can thus be recommended for primary implantation.