Ceramic/Ceramic wear couple
The product features suggest that a long implant lifetime is a real possibility
The possibility that BIOLOX®forte ball heads and cup inserts can provide the lowest wear and the longest implant lifetime is due to the properties of the product, namely:
- Excellent biocompatibility and corrosion resistance in the human body environment
- Excellent surface finish and dimensional stability
- High hardness and superior wettability.
Specially suited for active patients
A ceramic wear couple is particularly beneficial for active patients, whose higher body weight and activity level place higher demands on the materials and, if a wear couple containing polyethylene is used, can lead to an increased risk of early implant failure as a result of osteolysis. BIOLOX® ceramics cause no allergic reactions. The use of ceramic wear couples in preference to metal - polyethylene ones is recommended in the professional literature for artificial hip joint applications on account of the minimal wear and excellent biocompatibility of the ceramic - ceramic wear couple.
Minimal wear for long implant lifetime
BIOLOX®forte - BIOLOX®forte wear couples offer the best wear resistance, the lowest wear volume and the lowest long term wear rate of all wear couples. According to Greenwald and Garino the linear wear rate, as determined from explanted devices, is less than 0.005 mm per year, and is consequently up to 100 times lower than that for metal - polyethylene wear couples. In fact, laboratory tests using hip simulators give wear rates of less than 0.001 mm per year. This implies a wear rate which is roughly 200 times smaller than for a metal - polyethylene combination. In a ceramic wear couple the wear rate is almost independent of the ball head diameter and the ball head size has almost no effect on the wear process. The use of ceramic components eliminates polyethylene wear debris and so makes a longer implant lifetime a real possibility.
In vivo Wear Rate Study by Greenwald and Garino
In vivo linear wear rate for different wear couples: BIOLOX®forte - BIOLOX®forte had the lowest rate of all.
Source: Elke R. Particle Disease: Status and Today’s Solution. Garino J, Willmann G. Bioceramics in Joint Arthroplasty.
Georg Thieme Verlag Stuttgart, New York 2002: 3
Greater Range of Motion, Higher Joint Stability and Lower Wear
The wear rate is almost independent of the ball head diameter and large ball heads do not significantly effect the wear process. On the other hand, if a large ball head is used in a polyethylene wear couple a significantly increased amount of polyethylene wear debris is produced.
Hip Simulator Wear Testing of BIOLOX®forte
1)1 million cycles corresponds to the number of steps taken by
a patient in one year
Ceramic Wear Particles exhibit Lower Biological Activity
In selecting the ideal wear couple for an active patient it is necessary to take into account the osteolytic potential of each individual wear couple. In comparison with other wear couples, ceramic wear couples generate wear debris which has the lowest biological activity level.
Ceramic Wear Particles exhibit Lower Osteolytic Potential in comparison to Highly Cross-Linked Polyethylene
Experiments show that ceramic wear couples exhibit an osteolytic potential, which is roughly 50 times lower than for highly cross-linked polyethylene. This is as a result of both the low wear volume and low biological activity of ceramic wear particles.
No Three-Body Wear caused by Foreign Particles
With polyethylene wear couples three-body wear can occur. This is due to the trapping of hard foreign particles between the wear couple surfaces. These particles may be pieces of bone cement or bone. This problem is completely eliminated by the use of ceramics as the articulating surfaces are so hard that they are not affected by the cement or bone particles. Even the use of highly cross-linked polyethylene cannot adequately solve this problem.