Question

3 - You are working on an improved lightly cross-linked polyethylene (+[CH2]n-) hip replacement socket that releases a cocktail of water soluble anti-inflammatory drugs after implantation and is coated with type I collagen to allow bio-recognition and promote tissue integration. The polyethylene you are using is highly shear thinning, a necessity for the process you are using to form the socket. 1. How would you confirm the polyethylene has the correct rheology? 2. How would you quantify the components of the anti-inflammatory drug cocktail? 3. How would you prove the coating is type I collagen? 4. How would you characterize the polyethylene, including: a. backbone chemistry b. crystallinity c. molecular weight distribution

Answer 1

We can confirm that the polyethylene has the correct rheology if the polyethylene has a normally distributed penetration in the replacement area. According to the statistical analysis, the penetration value may range less than 0.05 to be significant in achieving the correct rheology. Also, Ultra-High Molecular weight polyethylene is considered more precise and have a steady-state wear property than the highly cross-linked polyethylene. But, the latter is used in Total Hip Arthroplasty (THA) as there are no significant differences between the two as the Oxford hip scores ranges for 39.5 for Highly cross linked one and 42.5 for the Ultra-High Molecular polyethylene.