Improved wear performance with crosslinked UHMWPE and zirconia implants in knee simulation

Abstract

BackgroundSuggestions for improved wear performance of total knee replacements have included replacement of standard CoCr femoral components with ceramic and replacement of 3.5-Mrad ultra-high molecular weight polyethylene (UHMWPE) inserts with 5-or 7-Mrad UHMWPE inserts. The ceramic materials used clinically have included alumina, zirconia ceramic and oxidized zirconium.Patients and method We compared both CoCr and zirconia versions of the Bi-Surface knee replacement in a 6-station knee simulator using alpha calf serum for lubrication (20 mg protein per mL) to evaluate the relative bearing performance.Results We studied the 4-way knee simulation of implant materials: zirconia ceramic, CoCr, 3.5-Mrad UHMWPE, and 7-Mrad UHMWPE. With CoCr femoral components, the 7-Mrad UHMWPE resulted in a 5-to 8-fold reduction in wear compared to the 3.5-Mrad insert. With the 3.5-Mrad insert, the zirconia bearing provided approximately 4-fold wear reduction compared to CoCr. These wear rates with standard UHMWPE were similar to published wear studies on entire knees. With the exception of the CoCr/7-Mrad and ZrO 2 /3.5-Mrad combinations, the wear differences were statistically significant.Interpretation The ZrO 2 /7-Mrad UHMWPE combination gave the best performance, with no measurable wear over the 5.5 million cycle test duration.

Effect of joint laxity on polyethylene wear in total knee replacement

“…However, the effect of increased laxity on implant wear is unknown. Furthermore, most wear studies to date have not sufficiently simulated the ligaments (D'Lima et al, 2001;Laurent et al, 2003;Tsukamoto et al, 2006). At best, mechanical springs were used to replicate the ligaments (Benson et al, 2001;Schwenke et al, 2005;Walker et al, 1997).…”

A peritoneal-based automated wearable artificial kidney

“…Decades of wide spread and increasing use of Zr compounds in medical practice have so far not been associated with clear evidence for Zr toxicities. Examples for successful medical applications include Zr-containing deodorant sticks, aerosol antiperspirants and poison-oak lotions [53], as well as life-long, internal placement of Zr-containing implants in dental restorative practice [54], in total knee [55] and hip [56] replacement, and in middle-ear ossicular chain reconstruction surgery [57]. Sorbent hemodialysis, using Zr-based hemodialysate regenerating cartridges, has been in use for the treatment of acute renal failure and end-stage renal failure patients since 1973 [20].…”

Patients’ perspective on controversial issues in total knee arthroplasty

“…These findings may be prompting health care providers to appreciate that the real value of MIS can be realized only when the surgical accuracy, safety, and high reliability are not compromised. While total hip arthroplasty has a long history of ceramic prosthesis, TKA has not been considered good for the application of ceramic components due to the concern over their mechanical properties [12,13,19,26]. Recently a great deal of attention has been paid to the ceramic femoral component which is claimed to be advantageous over traditional cobalt-chrome component in longevity [12,13,19,27].…”