Wear Analysis of Tibial Inserts Made of Highly Cross-Linked Polyethylene Supplemented with Dodecyl Gallate before and after Accelerated Aging

Abstract

The wear of the tibial insert is one of the primary factors leading to the failure of total knee arthroplasty. As materials age, their wear performance often degrades. Supplementing highly cross-linked polyethylene (HXLPE) with dodecyl gallate (DG) can improve the oxidation stability of tibial inserts for use in total knee arthroplasty (TKA). This study aimed to evaluate the wear resistance of HXLPE supplemented with DG (HXLPE-DG) tibial inserts before and after accelerated aging. HXLPE-DG tibial inserts were subjected to wear testing of up to 5 million loading cycles according to ISO 14243, and the resulting wear particles were analyzed according to ISO 17853. The wear rate, number, size, and shape of the wear particles were analyzed. The average wear rate of the unaged samples was 4.39 ± 0.75 mg/million cycles and was 3.22 ± 1.49 mg/million cycles for the aged samples. The unaged tibial inserts generated about 2.80 × 107 particles/mL following the wear test, but this was considerably lower for the aged samples at about 1.35 × 107 particles/mL. The average equivalent circle diameter (ECD) of the wear particles from the unaged samples was 0.13 μm (max: 0.80 μm; min: 0.04 μm), and it was 0.14 μm (max: 0.66 μm; min: 0.06 μm) from the aged samples. Moreover, 22.1% of the wear particles from the unaged samples had an aspect ratio (AR) of >4 (slender shape), while this was 15.4% for the aged samples. HXLPE-DG improves the wear performance of the material over time. HXLPE-DG is a novel material that has been demonstrated to have antiaging properties and high wear resistance, making it a promising candidate for use in TKA. Nevertheless, the results are preliminary and will be clarified in further studies.

Mechanical alignment tolerance of a cruciate-retaining knee prosthesis under gait loading—A finite element analysis

“…However, recent studies have shown that a neutral alignment did not improve the clinical outcome or survival rate, and a tolerance of 3° varus to 3° valgus could not be considered a “safe zone” with modern personalized alignment strategies, especially for an updated prosthesis ( Tibbo et al, 2021 ; Schelker et al, 2022 ). A possible reason is considerable differences in the design of contemporary knee prostheses, which can affect the mechanical behavior and wear performance ( Asseln et al, 2021 ; Zhang et al, 2021 ; Su et al, 2022 ). Although advanced techniques, like personalized specific instrumentation, navigation systems, and robotic surgeries, have improved surgical precision and alignment accuracy, malalignment is still a common complication.…”