Proposition of a new classification for scapholunate instability

Scapholunate (SL) instability is the most common pattern of instabilities in the wrist. If untreated or undiagnosed, it may lead to degenerative changes with SLAC (scapholunate advanced collapse) wrist. There are a few of of well-known SL instability classifications. The one that takes into account a dynamic or static nature of SL instability is the most accepted and used. The arthroscopic classifications are also becoming more and more popular. The aim of the study was the critical review of most popular classifications of SL instability, yet at the same time we proposed a new SL instability classification. Results. The new classification was found to be very useful in the process of diagnosis and decision making concerning further treatment of patients with SL instability in our department. Conclusions. The proposed new classification combines the opportunity of evaluating the scapholunate interosseus ligament (SLIL) tear and lesions of the secondary static stabilizers of SL ligament complex that can coexist with or without DISI deformity (Dorsal Intercalated Segmental Instability).