In vitro comparison of the two hard-hard articulations for total hip replacements.
Polyethylene particle disease is one of the major causes of late aseptic loosening of total hip replacement. Two hard-hard articulations (alumina-on-alumina and metal-on-metal) have been developed in Europe as an alternative to the ultra-high molecular weight polyethylene (UHMWPE) articulations. Even though these hard-hard articulations are on the market and numerous reports have been published about them, only a very limited number of studies allowing a direct in vitro comparison of the two articulations have been published so far. This paper compares in vitro these two types of articulation (alumina-on-alumina and metal-on-metal), which have been tested with a hip simulator for their tribological behaviour using exactly the same experimental methodology. This comparison shows that these two types of hard-hard articulation have very similar abrasive wear behaviour with four main features: 1. A running-in wear period (1 x 10(6) cycles) gives a cumulative wear of about 20 microns with head diameters of 28 mm. 2. After the running-in wear, there is a stabilization of the linear wear behaviour with a low linear wear rate/10(6) cycles for both types of articulation. 3. The volumetric wear rate of both articulations (< 2.0 mm3/year for head diameters of 28 mm) is significantly lower than that observed for metal-on-polyethylene or ceramic-on-polyethylene articulations having the same head diameter. 4. Abrasive wear is readily apparent (indicating a mixed lubrication regime) with both types of articulation. The extremely low wear performance of these articulations is confirmed and they constitute a low-wear alternative to the UHMWPE articulations currently used.
Rieker
C
C
Sulzer Orthopedics Limited, PO Box 65, CH-8404 Winterthur, Switzerland.
Konrad
R
R
Schön
R
R
D019644:Arthroplasty, Replacement, Hip; D002516:Ceramics / Q000032:analysis; D004867:Equipment Design; D017276:Friction; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D066298:In Vitro Techniques; D008153:Lubrication; D008422:Materials Testing; D008670:Metals / Q000032:analysis*; D011475:Prosthesis Failure; D014481:United States
D008670:Metals