Prospective long-term follow-up of the cementless bicontact hip stem with plasmapore coating.

AIM: A prospective long-term study of the first 250 cementless Bicontact stems implanted in the BG Trauma Centre, Tuebingen, Germany.

METHOD: All of the patients in this series (treatment period June 1987 to April 1990) who were still contactable were invited for clinical and radiological follow-up. The radiographs were analysed for signs of loosening in the form of Gruen lysis zones, stress shielding, subsidence behaviour, heterotopic ossification and spot welds.

RESULTS: The average follow-up period was 17.8 (16.7 - 19.5) years. The overall rate of follow-up was 65 % (162 of 250) and 91 % of patients who were still alive (162 of 179). The average patient age was 56.2 years at the time of operation and 74.0 years at follow-up. The average HHS was 81.6 points. In the course of the first 10 years (up to 03/1998), a total of 8 stem revisions had to be performed. In the period from 03/1998 to 01/2007, 2 cases of loosening requiring revision occurred in the patients still alive at the time of follow-up. The survival rate calculated was thus 95.6 %.

CONCLUSION: These outstanding results provide enduring support for the philosophy of the cementless and bone-preserving fixation principles underlying the Bicontact hip stem with proximal intertrochanteric transmission of forces and high primary rotational stability.