Large Diameter Heads and Liners

For Trilogy and Trabecular Metal Modular Cup Systems

The Trilogy and Trabecular Metal Modular Cup systems use the same liners which are available in many configurations including 36 and 40mm internal diameter articulations.

Large Diameter Heads and Liners

Large Head Philosophy

Increased stability and decreased dislocation is the large head philosophy. The philosophy assumes low wear characteristics of the highly crosslinked polyethylene. The radius of a femoral head determines the distance needed to travel out of the acetabulum to dislocate. The larger the head, the greater distance it needs to travel out of the liner to cause dislocation.

Benefits

The main benefits of using these larger diameter articulations are an increased range of motion and an increased resistance to dislocation.  There are benefits to both the patient and the healthcare provider as there remains a significant number of revision operations performed for impingement and dislocation. 

Large Diameter Heads and Liners

Increased stability with larger head sizes (above) and increased range of motion with larger head sizes (below).

Large Diameter Heads and Liners

These larger diameter articulations are made possible due to the use of Longevity highly crosslinked polyethylene which is more wear resistant than conventional polyethylenes.  In a prospective clinical study, Longevity polyethylene has demonstrated a 25 fold reduction in linear wear in vivo (from 0.174mm/yr for conventional UHMWPE to 0.007mm/yr for Longevity highly cross linked UHMWPE)1.

References

  1. In Vivo Comparative Wear Study of Traditional and Highly Cross-linked Polyethylene in Total Hip Arthroplasty.  Manning et al. Journal of Arthroplasty Vol. 20 No. 7 2005