iPoly™ XE

ConforMIS iPoly XE prevents oxidative degradation of polyethylene.

FTIR analysis was performed on samples of the iPoly XE sterilized via vaporized hydrogen peroxide (gas plasma) after an exhaustive extraction in hexane and two weeks accelerated aging. Accelerated aging was performed per ASTM F2003 (oxygen environment a temperature of 70°C ± 1°C and a pressure of 73psi ± 1psi for 14 days). Samples were tested at two different time points, immediately after accelerated aging, and after 5 million cycles of wear. The oxidation index was calculated using the method described in ASTM 2102. Results demonstrate that there was no measured oxidation index (Oxidation index equal to 0 for all samples) for any of the aged samples pre- or post-wear, indicating that the residual Vitamin E remaining following exhaustive extraction is sufficient to stabilize any free radicals.

ConforMIS iPoly XE samples were machined from GUR1020 polyethylene material blended with alpha-tocopherol (Vitamin-E), compression molded and gamma-irradiated. The material was annealed and compressed prior to machining.

Bench testing is not necessarily indicative of clinical performance.

ConforMIS iPoly XE maintains mechanical strength after accelerated aging.

Small Punch Testing per ASTM F2183 was conducted on aged and unaged samples of the iPoly XE sterilized via vaporized hydrogen peroxide (gas plasma). There was no significant decrease (p=0.41) in ultimate load of aged and unaged iPoly XE samples. The ultimate load of the iPoly XE material before and after aging was 94.8 ± 4.9N and 97.5 ± 5.8N. Accelerated aging was performed per ASTM F2003 (oxygen environment; a temperature of 70°C ± 1°C and a pressure of 73psi ±1psi for 14 days).

Tensile testing per ASTM D638 was conducted on aged and unaged samples of the iPoly XE. There was not a significant decrease in ultimate tensile strength (p=1.0) or yield strength (p=0.20) of the iPoly XE material. The ultimate tensile strength of the iPoly XE material before and after accelerated aging was 56.40 ± 2.70 MPa and 56.40 ± 2.30 MPa. The tensile strength at yield of the iPoly XE material before and after accelerated aging was 23.20 ± 0.45 and 22.80 ± 0.45 MPa.

ConforMIS iPoly XE samples were machined from GUR1020 polyethylene material blended with alpha-tocopherol (Vitamin-E), compression molded and gamma-irradiated. The material was annealed and compressed prior to machining.

Bench testing is not necessarily indicative of clinical performance

ConforMIS iPoly XE maintains the mechanical strength of conventional UHMWPE under tensile testing.

Tensile testing was conducted on aged samples which were sterilized via vaporized hydrogen peroxide (gas plasma). Accelerated aging was performed per ASTM F2003 (oxygen environment; a temperature of 70°C ± 1°C and a pressure of 73psi ±1psi for 14 days). There was no significant difference (p=0.12) in the yield strength of the iPoly XE material when compared the conventional polyethylene. The yield strength of the iPoly XE material and the conventional polyethylene was 22.8 ± 0.45 MPa and 22.3 ± 0.55 MPa. There was a statistical difference (p=0.01) in the ultimate tensile strength of the iPoly XE material and the conventional polyethylene. The ultimate tensile strength of the iPoly XE and conventional polyethylene material was 56.4 ± 2.3 MPa and 43.2 ± 8.34 MPa. The ultimate tensile strength of the iPoly XE was higher than that of the conventional polyethylene.

ConforMIS iPoly XE samples were machined from GUR1020 polyethylene material blended with alpha-tocopherol (Vitamin-E), compression molded and gamma-irradiated. The material was annealed and compressed prior to machining.

ConforMIS conventional UHMWPE samples were machined from direct compression molded GUR 1020 polyethylene material and sterilized using VHP Gas Plasma sterilization.

Bench testing is not necessarily indicative of clinical performance

ConforMIS iPoly XE tibial inserts had a reduced wear rate than that of conventional compression molded UHMWPE inserts bearing the same geometry.

The test samples were machined from the iPoly XE material or standard GUR1020 (control samples). The samples were sized to represent the smallest sized iTotal right knee implant. The conventional polyethylene and iPoly XE liners had identical articular geometry and a minimum thickness of 6.1mm. All samples were sterilized via vaporized hydrogen peroxide (gas plasma) prior to testing. Prior to testing the sterilized iPoly XE test samples were accelerated aged per ASTM F2003 (oxygen environment; a temperature of 70°C ± 1°C and a pressure of 73psi ± 1psi for 14 days).

The iPoly XE tibial inserts had a gravimetric wear rate that was 48.2% less than that of the conventional compression molded UHMWPE inserts with the same articular geometry.

Testing was conducted on an AMTI 6-station displacement controlled knee simulator (AMTI 6-Station Knee Simulator for five million cycles using ISO 14243-3 gait waveforms and a bovine calf serum solution with a protein concentration of around 18.5 g/L). Test samples were iPoly XE tibial inserts paired with the iTotal femoral component. Conventional UHMWPE inserts paired with the iTotal femoral component were used as controls for the study. The mean gravimetric wear rate for the aged iPoly XE components inserts was 6.50 ± 2.67 mg/MC, and that of the conventional polyethylene components was 12.58 ± 1.32 mg/MC. The aged iPoly XE UHMWPE tibial bearings exhibited a 48.2% reduction in wear as compared to the unaged conventional components.

ConforMIS iPoly XE samples were machined from GUR1020 polyethylene material blended with alpha-tocopherol (Vitamin-E), compression molded and gamma-irradiated. The material was annealed and compressed prior to machining.

ConforMIS conventional UHMWPE samples were machined from direct compression molded GUR 1020 polyethylene material and sterilized using VHP Gas Plasma sterilization.

The results of in-vitro knee wear simulator tests have not been shown to quantitatively predict clinical wear performance.