Abstract
Aim: The aim of our retrospective study was to evaluate the precision of implantation of two different resurfacing systems and if incorrect positioning is a risk factor for implant failure.
Method:. We started with the Birmingham Hip Resurfacing system (MMT,UK) and later introduced the Durom resurfacing system (Zimmer). We analysed the follow-up rx of all patients operated in our clinic.
We measured the inclination of the cup, the CCD-angle of the head component, the alignement in respect to the neck axis, if the component had an eccentric position or if superior or inferior notching had occured. We compared the rate of failure of the two systems.
Patients: In 90 patients a Mc Minn hip resurfacing system was implanted. The mean age in this group was 52 years (range 29 – 68 years). There were 64 male and 26 female patients.
In 75 patients we implanted a Durom resurfacing system. The mean age in this group was 53 years (range 20 – 72 years). There were 55 male and 20 female patients.
Results: In both groups the mean CCD angle was higher than before surgery, indicating that the head component was usually implanted in a slight valgus position. In 20 % of the cases component alignement was not ideal in both systems. There were four revisions of patients with the Durom system and three revision of patients with the McMinn system. The main reason for failure was weakening of the superior neck portion.
Conclusion: As we were in the learning curve in hip resurfacing in a high number of cases positioning of the implant was not as it should be. This remained in most cases without clinical consequences but weakening of the superior neck portion seems to be the main reason leading to failure.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
