New concept of scapholunate dissociation treatment and novel modification of Brunelli procedure - anatomical study

BACKGROUNDS This paper describes a novel method in treatment of scapholunate dissociation accompanied with rotatory subluxation of the scaphoid. The idea of this method is to create a kind of axial lever that can fully reconstruct anatomical relationship between the scaphoid and the lunate, with no involvement of extrinsic ligaments, and with simultaneous restriction of pathological alignment of the scaphoid. Based on this technique, we have also proposed a new modification of Brunelli procedure in scapholunate dissociation with rotatory subluxation of the scaphoid and dorsal intercalated segmental instability. METHODS At the initial stage of the study, 20 human wrists fixed in Ethanol were used, followed by 12 fresh human wrists used in part two. The first stage included functional, biomechanical and strength tests carried out by means of a 5 kg load and intended to find the most anatomical and durable treatment method. The second stage involved testing the proposed methods on fresh cadaver wrists. RESULTS We have discovered that the new method is able to recreate anatomical forces and properties of scapholunate ligament; what's more, it can also prevent rotatory subluxation of the scaphoid. The performed strength tests have proven that it is possible to treat scapholunate instability also in case of dorsal intercalated segmental instability. CONCLUSIONS We highly recommend using both the new technique and the new modification of Brunelli procedure for treatment of scapholunate dissociation in both dynamic and static instabilities.