CONVENTIONAL POLYETHYLENE VERSUS HIGHLY RETICULATED POLYETHYLENE: COMPARATIVE RANDOMIZED STUDY OF 102 CASES WITH 4 YEARS 8 MONTHS FOLLOW-UP

Abstract

Purpose of the study: The limitations of conventional polyethylene are well known (osteolysis). New bearing surfaces have been proposed for hip arthroplasty including new-generation polyethylene products.

Material and methods: We compared four bearings including one metal-on-metal and one ceramic-on-ceramic bearing with results not available for analysis at this 4 years 8 month follow-up. The comparative randomized study included 102 first intention total hip arthroplasties comparing a single variable: the bearing. Common elements were: metal-back press-fit cup (Fitmore) and cemented anatomic stem (Emeraude). Variable elements were: alpha Sulène insert + 28 metal head (n=53) versus alpha Dursul insert + 28 metal head (n=49). Clinical outcome was assessed with the Postel-Merle-d’Aubigné score and the Harris score. Radiological outcome was assessed with: wear (EBRA, semiautomatic linear radiographic penetration), cup migration according to EBRA, and radiographic changes in zone 7.

Results: After checking the validity of the files studied, clinical outcome was strictly the same for the two series: wear Sulène polyethylene 0.21 mm; Durasul polyethylene 0.1 mm. Cup migration was: Sulène polyethylene 0.13 mm; Durasul polyethylene 0.08 mm. Modifications of zone 7 were: Sulène polyethylene 17.8%; Durasul polyethylene 6.6%.

Conclusion: With 4 years 8 months follow-up, several elements are in favor of the new-generation polyethylene inserts, confirming theoretical results with mathematical models. This length of follow-up is insufficient to draw formal conclusions concerning in vivo aging.