A support structure for use with an external fixator assembly including, but not limited to, a fixator assembly for the ankle area of the body which may further include an ankle stabilization portion. The support structure is similar in function but distinguishable in structure from a “halo-ring” and comprises a base having a substantially annular configuration and being operatively disposed in at least partially surrounding relation to a leg area which corresponds to the stabilized ankle area. An extension assembly includes at least one but preferably a plurality of two elongated extension members extending outwardly from the base and in spaced relation to and substantially aligned with the ankle stabilization portion. The base and the two extension members are structured for connection to a plurality of struts which may be variably and selectively disposed in interconnecting relation to the ankle stabilization area and/or other portions of the external fixator assembly.