Section 2. Total Knee ArthroplastyKnee Bearing Technology: Where is Technology Taking Us?
Section snippets
Materials and Methods
X3 is composed of GUR 1020 polyethylene, which is irradiated and annealed in 3 sequential steps—each consisting of 30 kGy of irradiation followed by annealing for 8 hours at 130°C in air. Following these 3 steps, the part is machined and gas plasma sterilized.
It is crucial that the bearing material properties be fully characterized. Further, the impact of time in the harsh environment of the host on these material properties must be investigated through an accelerated aging regimen. The
Results
Tensile yield strength and ultimate yield strength were statistically the same (P = .11 and .12, respectively) between the conventional and X3 polyethylene before accelerating aging (Table 1). Elongation for X3 was lower than for conventional polyethylene. However, it is comparable to that of direct compression molded 1900 material that has shown excellent clinical performance [8].
Further, the tensile properties of the X3 were statistically unaffected by the accelerated aging challenge.
Discussion
Satisfactory wear and mechanical performance of implant bearing surfaces may be dependent upon a number of factors, such as how well the implant is positioned, the demands of the host, the material properties, the locking mechanism, and the geometry of the design 9, 10. Care must be exercised by the surgeon to balance the soft tissues and appropriately align the knee. Technologies such as navigation may aid in accurate and reproducible positioning 11, 12, 13. Patient expectations should be
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No benefits or funds were received in support of the study.