LONG TERM SURVIVAL ANALYSIS OF SPONGIOSA METAL I CEMENT LESS TOTAL HIP PROSTHESIS BETWEEN JAPAN AND GERMANY

Abstract

Introduction: Unique spongiosa like surface structure was introduced in 1982 by ESKA implants Germany. It is called “Spongiosa-Metal I surface” The purpose of this retrospective study is to report and compare long term results of Spongiosa Metal I total hip prosthesis in Japan and Germany.

Method: In Japan, between June 1986 and August 1990 total 113 prostheses were implanted and consecutive 106 implants could be evaluated. In Germany, between May 1983 and December 1985 total 209 prostheses were implanted and consecutive 165 implants could be evaluated. The all evaluated prosthesis combined ceramic head and polyethylene inlay.

Results: In Japan, average follow up period was 17 years. 85% of the patients had retained the original prostheses (cup, stem, ceramic head, and inlay). Survival rate was investigated by Kaplan-Meier method. Survival rate for the cup component was 95%, and for the stem component was 93%. In Germany, average follow up period was 21.8 years.

88.5% of the patients had retained the original prosthesis. Survival rate for the cup component was 95%, and for the stem component was 85%.

Discussion: Main reason of the revision surgery was the ceramic head fracture (7 implants 6%) in Japan and the stem component loosening (14 implants 8%) in Germany.

There was no ceramic head fracture in Germany. We thought that beating with the hammer when we install the ceramic head to the taper was one problem. Stem loosening was seen in undersized stem component. On the other hand, survival rate for the cup component was 95% in Japan and Germany. This was good result in comparison with other reports about long term survival.

Conclusion 85% of the patients had retained the original prostheses average 17years in Japan and 88.5% average 21.8 years in Germany. Main reason for the revision surgery is stem loosening and ceramic head fracture. Survival rate for the cup component was 95% in Japan and Germany. We are convinced with this spongiosa metal surface can bear long term use.