Abstract
Introduction and purpose: Highly cross-linked polyethylenes (HXLPE) sterilized in an air-free environment have been used to prevent osteolysis and loosening of implants. This prospective randomized study analyzes the results of a series in which one single type of prosthesis but made with one of two different kinds of polyethylene (PE) has been used.
Materials and methods: We assessed 45 Allofit cups with a Sulene-PE liner (sterilized in nitrogen) and 45 with Durasul-PE liner (highly cross-linked) associated with an Alloclassic stem (femoral head: 28 mm) with a minimum follow-up of 5 years (mean 66.3 months). Femoral head penetration was analyzed by means of a digital program at 6 weeks, and at 6 and 12 months and once a year, using the Dorr method given the non-spherical shape of the cups.
Results: All assessed hips had good outcomes determined clinically and by x-rays. There was no loosening of any component. There were no radiolucent lines or osteolysis. Femoral head penetration at 6 weeks was 47.4% less in the Durasul group (0.19+0.06 mm for the Sulene-PE and 0.09+0.03 for the Durasul-PE [p< 0.0001]). Mean annual penetration was 20% less in the Durasul group (0.04+0.02 and 0.008+0.008 [p< 0.0001] respectively. The differences increased by the third year. Mean penetration at 5 years was 39.1% less in the Durasul group (p< 0.0001).
Conclusions: There was significant femoral reduction in the Durasul-PE group. Long term results are necessary to confirm that these prostheses lead to a lower rate of osteolysis.
The abstracts were prepared by E. Carlos Rodríguez-Merchán, Editor-in-Chief of the Spanish Journal of Orthopaedic Surgery and Traumatology (Revista de Ortopedia y Traumatología). Correspondence should be addressed to him at: Sociedad Española de Cirugía Ortopédica y Traumatología, calle Fernández de los Ríos 108, 28015-Madrid, Spain
