Question

The success of large joint reconstruction implants with expected life times >20 years has contributed to the popularity of the procedures. Describe the wear testing protocols for arthroplasty devices AND the basis for the number of cycles for the total joint replacement device.

Answer 1

Wear testing protocols for arthroplasty devices and it's cycles:

Total joint replacement improved their standard of care for end-stage population.. especially for degenerative hip and knee disease .it will be made up of metal or ceramic components articulating against ultra - high molecular weight polyethylene (UHMWPE).. charecteristics of this biomaterials influenced by their extend of crosslinking, it improves wear resistance..After implantation pin-on-disk (POD) testers they will screen and provide warranty.if POD testers can not able to reproduce this wear mechanism..multidirectional POD testers will screen and provide rank the tribological properties with different formulation relevant with ultra- high molecular weight polyethylene..oxidation of gamma sterlized UHMWPE happen once exposure of O2 in air and after implantation in the body..it increases wear rate of the material Theoretical.. The distribution of wear rates tested using shapiro-wilk test and it was not normal..retrived implants have more wear resistance than shelf- aged implant..so nonparametric statistical testing was used..each pin has different chamber filled with 15ml lubricant it maintain at 37+ 1 degree c.

The test was carried out to 2.5million cycles at 1.0H2 ...Gravimetric measurements with 0,0.25,0.50, .1.00, 1.50, .2.00 and 2.50 million cycles used in calibrated digital scale..Total 10million cycles will be done..in that during ASTM test period (10-15million) with gravimetric wear rate of 0.14 +/-0.06mg/million cycle was estimated..