The Diagnostic Value of the Scapholunate C-Sign: A New Tool for Detecting Through-and-Through Scapholunate Interosseous Ligament Injuries

Abstract

Purpose: Currently, there is a lack of a validated clinical sign to accurately detect through-and-through or complete injuries to both the dorsal and volar scapholunate interosseous ligament. The aim of this study was to evaluate the validity of a clinical sign for detecting this condition. Methods: This study included 28 patients with suspected high-grade tears of the scapholunate interosseous ligament who underwent the C-sign maneuver. Each patient received a comprehensive evaluation, including a history, physical examination, magnetic resonance imaging interpretations by a musculoskeletal radiologist, and wrist arthroscopy. The diagnostic performance of the C-sign was assessed by calculating its sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratios, and overall accuracy, using wrist arthroscopy as the reference standard. Results: The C-sign, which includes both a characteristic patient reported symptom and a corresponding physical examination finding, demonstrated high sensitivity and specificity (86% and 83%, respectively) when present together. The positive likelihood ratio for the C-sign was 5.18, and the negative likelihood ratio was 0.16. The overall diagnostic accuracy was 85.7%. The diagnostic performance decreased when only one component of the C-sign was considered alone. Conclusions: The scapholunate C-sign is a valuable clinical indicator, demonstrating good diagnostic accuracy in detecting high-grade, through-and-through scapholunate interosseous ligament injuries that may warrant surgical intervention. Type of study/level of evidence: Diagnostic II.