Abstract
Background and aim
A significant reduction in wear using Durasul highly cross-linked polyethylene (PE) versus Sulene polyethylene (sterilized with nitrogen) at 5 and 10 years have been reported previously. We ask if the improvement observed at the earlier follow-up continues at 15 years.
Methods
Between 1999 and 2001, 90 hips underwent surgery using the same cementless cup and stem: 45 received Allofit cups with a Sulene-PE liner and 45 Allofit cups with a Durasul-PE liner, both associated with an Alloclassic stem (28 mm metallic femoral head). 66 hips of this prospective comparative study were available over a minimum follow-up of 15 years. Linear femoral head penetration was estimated digitally at 6 weeks, at 6 and 12 months and annually thereafter, using the Dorr method, given the nonspherical cup shape. All radiographs were evaluated by the same author, who was not involved in surgery.
Results
2 hips in the Sulene group showed proximal femoral osteolysis, one of these was revised for stem loosening at 12 years. There was no loosening of any other prosthetic component. Femoral head penetration in the one year postoperative radiographs was 0.23 mm (range, 0.08–0.23) for the Sulene group and 0.10 mm (0.04–0.11) for the Durasul group (p<0.001). The mean yearly linear femoral head penetration was 68.8 % lower for the Durasul group: 0.020+0.018 mm for the Durasul and 0.062+0.051 mm/year for the Sulene group (p<0.001). Mean linear femoral head penetration at 15 years was 64.5 % less in the Durasul group (0.394+0.27 mm) than in the Sulene group (1.108+0.78 mm)(p=0.001).
Conclusions
There is a significant reduction in yearly linear femoral head penetration with the Durasul-PE. Confirmation that this reduction will result in less osteolysis requires continued follow-up studies.
