Volar intercalated segment instability as a result of spontaneous rupture of the supporting ligaments of the wrist due to longterm systemic steroid medication.

Linscheid and Dobyns (1972), in a classical article on post-traumatic instability of the wrist described two major types of instability, dorsal and volar. The dorsal intercalated segment instability (D.I.S.I.) was the more common and occurred with scapholunate dissociation and displaced scaphoid fractures. The instability occurred in these conditions as a result of the scaphoid losing its ability to support the carpus. They presented five cases of volar intercalated segment instability (V.I.S.I.) of which four were related to congenital ligament laxity and not to traumatic ligament disruption. In the one case of traumatic origin they felt that the capitolunate ligament was ruptured. However, more recent publications by Taleisnik, Prietto (1982) and Reagan, (1984) have proposed that for V.I.S.I. to occur the lunate triquetral interosseous ligament must be disrupted. We report this case as it demonstrates which ligamentous structures are torn for V.I.S.I. to occur. In addition, these ligament disruptions were pathological and occurred spontaneously as a result of longterm systemic steroid medication.