I don't but its never been disclosed. 10k mentions no other JDA.
I have a 2.5m payment from Zimmer after a Sintx milestone that Zimmer was involved with coupled with a 2.5m loan from Sonnys investment company to Sintx shortly thereafter. Plus evidence that Sonnys still developing hip/knee implants outside of Sintx and that Sonny was working for Zimmer directly in 2014 and likely still is. Pretty strong coincidence if not connected.