20. The improvement of claim 18 wherein the multi-start closure includes at least two helically wound forms, each form being one of a flange form, a v-thread, a square thread, a reverse angle thread and a buttress thread, the form mating with the first helically wound guide and advancement form.
18. In a medical implant, the improvement comprising: a) an open receiver member with spaced arms having inwardly facing surfaces, each with a helically wound guide and advancement form located thereon; and b) a helically wound multi-start closure member having an axis of rotation, the closure member rotatably mounted on the receiver member at the spaced arm inwardly facing surfaces.