I'm still working on tying this together, but Si3N4 implants were implanted in 86-88 in Australia. 10 years later a retrospecitive study is done, published 2004. Amedica was founded 1996 but didnt file a Si3N4 patent until 2002.
Zimmer Australia was founded 1998 or 2001. Ive seen two bloomberg articles on this.
Somehow Si3N4 went from Australia to Salt Lake City around the time of that 10 year study and Zimmer Australia's founding. First patent 2002 & then Dr Link from Zimmer acquired Centerpulse joins Amedica Oct 2003. Beginning in 2004, amedica begins Series offerings raising 31m by 2006. 2005 Dr. Bal meandors from Zimmer over to Amedica.
While I cant prove anything it looks like Zimmer arranged for tech to come to the States from the University of New South Wales to Amedica and then put its personnel to oversee its development. Pretty interesting 20 year play if accurate.