The "dark tendon sign" (DTS): a sonographic indicator for idiopathic trigger finger.

Although the diagnosis of "idiopathic trigger finger" (stenosing tenovaginitis) is normally based on clinical examination alone, to date there is no reliable evaluation defining this idiopathic disease beyond an exclusion of secondary causes or an unnecessary sonographic certification of high-grade impairment. By standardized assessment of 32 patients who retrospectively fulfilled the study inclusion criteria and their comparison to a matched group of volunteers, we defined the diagnostic efficiency of the here newly proposed sonographic dark tendon sign (DTS) alone, of impaired tendon gliding alone and the combination of these two features. Pulley thickness in patients and volunteers was significantly different. The combination of clinically impaired tendon gliding plus the DTS reached a sensitivity and diagnostic efficiency of 100%. We propose this diagnostic combination as the new first line assessment features for the quick definition of idiopathic stenosing tendovaginitis during daily routine