Abstract
Search for optimal shape of hip implant have gone on from 70th’s. Different shapes of hip cups and methods of their implantation, which were created within those years, indicate, that long term results of cementless arthroplasty are still not satisfactory.
The clinical and radiological results of cementless hip arthroplasty, which were performed with two types of shape cups (threaded spherical and threaded conical), were analyzed after at least 7 years follow up. Analysis was based on results 106 of cementless hip arthroplasties among 141, which were done during 1993 – 1996. The study concerned 58 threaded spherical cups (group A) and 48 conical (group B). Application of cups was randomized with respect to both sex and etiology of hip dysfunction and their implantation conditioned to possession of this type of implant on this moment.
The mean age of 63 women and 35 men ( in 8 both side) in the moment of implantation were 48,9 years ( 10,6)and ranged from 28 to 76 years. Mean time of follow up was 8,2 years( 1,4) and ranged from 7 to 10 years.
Pre- and postoperative clinical evaluation of hip function was carried out by means of Harris Hip Scale. Radiological evaluation was based on measurements of angle of inclination, horizontal and vertical migration of cup and radiolucent lines in DeLee-Charnley zones. Those measurements of last x-ray examination were compared with those, which were done immediately after arthroplasty.
There were 80% of excellent and good results and 17% poor results in clinical evaluation of group A. In radiological evaluation of this group mean horizontal migration was 1mm, and vertical was 2,5mm. Clinical and radiological symptoms of cup loosening were confirmed in 10 hips. The revision procedures were performed in 9 hips. In group B excellent and good clinical results were in 98% and poor results only in 2 % of treated hips. Radiological evaluation also showed less migration of cups. Mean horizontal migration was 0,3mm, and vertical was 0,7mm. Clinical and radiological symptoms of loosening were in 1 hip, which were treated by revision procedure.
Conclusion of our study is statement, that application of cementless threaded conical cup in hip arthroplasty give better clinical and radiological midterm results, than apllication of cementless threaded spherical cups.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
