Product Overview
Crown Cup XLE highly crosslinked vitamin E enhanced acetabular liners provide low wear while maintaining mechanical strength, reducing free radicals and oxidative degradation.
The XLE liners are manufactured using Ultra High Molecular Weight Polyethylene (UHMWPE) blended with vitamin E prior to consolidation and crosslinking. This provides a uniform distribution of the vitamin E and minimizes the elution effect found in diffused vitamin E liners. The gamma crosslinking and annealing process, developed in conjunction with Massachusetts General Hospital, grafts the vitamin E to the polyethylene molecule, resulting in a highly crosslinked material with excellent oxidative stability.
Low Wear
A patented gamma irradiation and mechanical annealing process, tailored to the vitamin E content, is used to achieve the desired crosslink density. An irradiation dose of 10 Megarad (Mrad) or 100 KiloGray (kGy) is imparted to the material prior to final gamma sterilization. This highly crosslinked polyethylene yields a reduced wear rate compared to conventional polyethylene.
Mechanical Strength
The mechanical annealing process quenches free radicals below the melt temperature, which maintains the crosslink density and provides improved mechanical strength over conventional polyethylene.
Oxidative Stability
Blending the vitamin E prior to consolidation allows the antioxidant to distribute uniformly throughout the material. Gamma crosslinking grafts the vitamin E molecules onto the polyethylene chains. This minimizes the elution effect found in diffused or doped vitamin E liners. The mechanical annealing process further quenches free radicals. The cumulative result is a material with oxidative stability that reduces oxidative degradation.
Manufacturing Process
Developed by Massachusetts General in conjunction with Cambridge Polymer.3
1. Compression molded, vitamin E blended polyethylene sheet is turned into bar stock
2. Bar stock is gamma irradiated at 10Mrd
3. Preheat bar and platen
4. Compress 2:1 under heat and cool
5. Recover at sub-melt temperature
6. Turn to final diameter
Size Offerings
Offered in Neutral, Extended Coverage, 10° Face changing, and +5 Lateralized options designed to allow the surgeon to optimize the femoral head size and restore patient anatomy. (https://www.exac.com/)
