A support structure implant for location within a bone cavity to support the bone which defines the cavity is formed from interlaced wires which extend from a first end of the structure towards an opposite second end. The structure flares outwardly from the first end to a maximum transverse dimension at a wide point between the first and second ends and tapers inwardly between the wide point and the second end to a constant cross-section throat portion at the second end. The structure includes a ring clamp at the second end to retain the wires in the throat portion which includes an internal support ring. The ratio of (a) the distance between the internal support ring and the interface between the tapering portion and the throat portion to (b) the diameter of the throat portion is not more than about 1Ø
