Clinical and radiological results with a 36-mm cobalt-chrome prosthetic head,cross-linked Durasul liners associated with Allofit cups: a more than 10-year follow-up period

Abstract

Background:

Highly cross-linked polyethylene is currently a common articulation surface used for total hip arthroplasty (THA).

Aim:

The aim of the present study is in vivo assessment of highly cross-linked Durasul polyethylene linear and volumetric wear when associated with a 36-mm prosthetic femoral head.

Methods:

We retrospectively reviewed clinical and radiographic data of 78 patients (81 hips) having primary THAs using Durasul liner combined with a 36-mm CoCr prosthetic head. All of them were followed for more than 10 years. Patient outcome was assessed with the Harris Hip Score (HHS) preoperatively and at last follow-up. 2-D prosthetic head penetration into polyethylene, 3D wear rates and cup migration were evaluated.

Results:

The preoperative and last follow-up HHS were 50.43 +/− 10.42 and 97.44 +/− 5.51 respectively. The annual penetration of the prosthetic head into Durasul^® liner was 0.029 +/− 0.003 mm. The annual linear penetration and volumetric wear extrapolation rates using Charnley and Ilchmann formulas were 37.84% and 57.76% respectively of that seen with conventional polyethylene liner. At last follow-up, the total loss of material in Durasul represents only 0.15% of the initial polyethylene mass. We did not observe any significant cup migration in the study group.

Conclusions:

Results are promising, and we believe that these data authorise the continued use of highly cross-linked polyethylene liner associated with a 36-mm prosthetic head for total hip arthroplasties in older patients. More long-term follow-up studies are mandatory before we feel comfortable with the project of using cross-linked polyethylene in young and active patients instead of ceramic-on-ceramic bearings.