Interobserver Reliability of the Amsterdam Severity Scale in Stenosing Tenosynovitis (ASSiST)

STUDY DESIGN: Interobserver reliability study. INTRODUCTION: A scale was developed to measure the severity of stenosing tenosynovitis: the Amsterdam Severity Scale in Stenosing Tenosynovitis (ASSiST). PURPOSE OF THE STUDY: To study the interobserver reliability of the ASSiST. METHODS: Patients suffering from various impairments in hand function were referred to our outpatient hand clinic. The grading of stenosing tenosynovitis was assessed independently. The observers were blinded for each other's results. The ASSiST distinguishes between a nodular and a diffuse form. The severity was graded from grades 0 to 3. RESULTS: Kappa coefficient for the distinction between the four grades was 0.72 (95% confidence interval [CI] 0.59-0.85) and for the distinction between the nodular and the diffuse forms 0.16 (95% CI 0.13-0.18). CONCLUSION: The ASSiST can be used to reliably assess the severity of stenosing tenosynovitis in both nodular and diffuse forms, but it does not differentiate between these two forms. LEVEL OF EVIDENCE: Not applicable