72 and be sized to be under at least some tension when the end cap 50 is assembled the implant 20 may be assembled in a variety of ways for example alignment pins 84 may be placed in holes 66 of the first portion 60 the first portion 60 is then coupled to the body 30 by sliding the first portion 60 onto the first end 34 from a direction normal to the longitudinal axis 32 such an approach allows the lips 64 of first portion 60 to slide under into the corresponding undercuts 39 on the corresponding protrusions 37 it should be noted that in the embodiments where the protrusions 37 are evenly spaced about the first end 34 the first portion 60 of the end cap 50 need not be positioned in a single particular orientation relative to the body 30 but can be put at any one of a variety of functionally equivalent positions for example if there are six protrusions 37 then the first portion 60 of the end cap 50 can be joined to the body 30 in any one of six different relative positions after the first portion 60 of the end cap 50 is joined to the body 30 the second portion 70 is then slid into position from the opposite direction with the alignment pins 84 being received in the holes 76 of the second portion 70 as with the first portion 60 the lips 74 of the second portion 70 are captured in the corresponding undercuts 39 joined in this manner the first and second portions.