LONG TERM SURVIVAL ANALYSIS OF SPONGIOSA METAL I CEMENT LESS TOTAL HIP PROSTHESIS IN JAPAN

Abstract

Introduction: “Spongiosa metal” this unique implant surface was introduced in 1982 by ESKA implants Germany.

Pore size was between 800 and 1500 microns with an overall porosity of 60%. The pore depth of the interconnecting surface structure reached up to 3000 microns.

The purpose of this retrospective study is to report the long term results of Spongiosa Metal I cement less total hip prosthesis in Japan.

Materials and Methods: Between 1986 and end 1990 total 113 prostheses were implanted and consecutive 106 implants could be evaluated.

The all evaluated prosthesis combined 28mm ceramic head and polyethylene inlay.

Results: Average follow up period was 17 years.

2 cups and 1 stem were revised by aseptic loosening.

2 stem breakage and 7 ceramic head fracture were seen while following up.

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%.

Discussion: Main reason of the revision surgery was the ceramic head fracture (7 implants 6%)

We thought that beating with the hammer when we install the ceramic head to the taper was one problem.

On the other hand, few aseptic loosening was seen while following up.

These results suggest that spongiosa metal system can bear for long term of use.

Conclusion: 85% of the patients had retained the original prostheses average 17years following up period.

Main reason for the revision surgery is ceramic head fracture.

We are convinced with this spongiosa metal surface can bear long term of use.