Fatigue Crack Propagation of UHMWPE - Medical Polymer Group

In recent years, efforts to improve the wear resistance of UHMWPE has led to the development of improved microstructural toughness. One such method includes radiation crosslinking of the UHMWPE chains, which greatly improves wear rate but at the cost of oxidative and fracture resistance. Studies in our lab have explored the role that radiation crosslinking, heat treatments, and antioxidants have played in the fatigue crack propagation resistance of UHMWPE utilizing a linear elastic fracture mechanics approach. We particularly focus on developing structure-property relationships that dictate crack growth through a combination of both mechanical testing and microstructural evaluation (SEM, TEM, DSC, etc.).

Recent efforts are currently focusing on how design features, such as notches included in hip and knee implants to improve fixation and kinematic stability, affect crack growth. This work derives from several retrieval studies recently published by our lab and collaborators in which stress concentrations played a key role in the failure of UHMWPE components. Ultimately this work seeks to further our knowledge of the role that microstructure, environment, and design plays on crack growth in UHMWPE.

Atwood, S. A., Van Citters, D. W., Patten, E. W., Furmanski, J., Ries, M. D., & Pruitt, L. A. (2011). Tradeoffs amongst fatigue, wear, and oxidation resistance of cross-linked ultra-high molecular weight polyethylene. Journal of the Mechanical Behavior of Biomedical Materials, 4(7), 1033-1045.

Pruitt, L. A., Ansari, F., Kury, M., Mehdizah, A., Patten, E. W., Huddlestein, J., … & Ries, M. D. (2013). Clinical trade-offs in cross-linked ultrahigh-molecular-weight polyethylene used in total joint arthroplasty. Journal of Biomedical Materials Research Part B: Applied Biomaterials. 101B (3), 476-484.

Ansari, F., Chang, J., Huddleston III, J., Van Citters, D., Ries, M., & Pruitt, L. (2013). Fractography and oxidative analysis of gamma inert sterilized posterior-stabilized tibial insert post fractures: Report of two cases. The Knee, 20 (6), 609-613.