. . . . . "The first and second implantable members 12, 14, respectively, or any part thereof, may be manufactured from or otherwise incorporate a plurality of biologically-compatible materials, including, without limitation, titanium or titanium alloys, stainless steel, cobalt-chromium alloys, vanadium, ceramic or ceramic materials, such as aluminum oxide and zirconium oxide ceramic, Nickel Titanium alloys," .