Introduction: We report the development of an arthroscopic severity score for scapholunate instability based on dynamic testing of the scapholunate joint.
Method: Seventy patients who had a scapholunate instability diagnosed by arthroscopy were reviewed. There were 21 static instabilities, 19 dynamic instabilities and 30 preradiographic instabilities. The arthroscopic finding was systematized. In the radiocarpal space the scapholunate interosseous ligament was seen and palpated. In the midcarpal space, the dynamic manoeuvre of dissociation was done using the examining hook.
Results: An arthroscopic classification was developed: in stage 0, it is impossible to put the tip of the hook between the scaphoid and the lunate; in stage 1, it is possible to put the tip of the hook between the scaphoid and the lunate; in stage 2, it is possible to create a scapholunate diastasis with the use of a twisting motion applied to the hook; in the stage 3, the 2.7-mm arthroscope passes between the scaphoid and lunate from the midcarpal to the radiocarpal space. We found 4 stage 1, 43 stage 2 and 23 stage 3.
Discussion: Even if other diagnostic tools such as the arthroscanner or MRI are able to diagnose scapholunate interosseous ligament tears, wrist arthroscopy is for us the Gold Standard to quantify and directly explore the scapholunate joint. The goal of the score of severity presented here is to guide the different therapeutic indications.