The Diagnostic Arthroscopic Application of the "Drive-In" and "Drive-Through" Signs in the Treatment of Symptomatic Scapholunate Instability

Abstract Scapholunate instability is the most commonly diagnosed and treated carpal instability. Diagnosis is challenging because of the wide spectrum of injury, ranging from dynamic to static instability. To complicate matters, scapholunate instability is often part of a global injury to the wrist, where additional wrist pathology can alter the clinical presentation and imaging findings. Defining scapholunate instability is challenging using current classifications. A retrospective review was performed over a 3.5-year period. All patients had their arthroscopic videos saved on a hard drive. Patients who had a wrist fracture were excluded. A total of 150 patients were included in this study. A total of 114 patients had a Drive-In Sign, with 67 of these only positive once the traction was removed. Thirteen patients had a Drive-Through Sign, with 12 of these being present while the traction was applied. Twenty-three patients had a negative Drive-In or Drive-Through Sign, and this was primarily caused by wrist ganglions (18 patients). This paper presents the arthroscopic “Drive-In” Sign and redefines the “Drive-Through” Sign as simple tests to define scapholunate instability.