Treatment of chronic scapholunate instability according to the functional demand of the wrist.

Scapholunate instability is the most common form of carpal instability. Complete scapholunate ligamentous complex failure can lead to pain, reduced functional performance, and scapholunate advanced collapse if untreated. The goal of surgery for chronic scapholunate instability (diagnosed later than 6 weeks) before onset of osteoarthritis is to correct the scapholunate instability in order to reduce pain while limiting loss of motion and protecting against osteoarthritis-related collapse in the long-term. Because many ligament reconstruction techniques have been described and not every patient is a candidate for a demanding procedure, we addressed the question of what is the best adapted treatment for each stage of chronic scapholunate instability? This article reviews the anatomy and biomechanical properties of the scapholunate complex and the current diagnostic tools in scapholunate instability. A treatment algorithm based on instability stage and the patient's functional demand is proposed. LEVEL OF EVIDENCE: III.