Modified Staged Finkelstein Test for the Identification of Intracompartmental Septum in Patients with De Quervain's Disease

Background: The intracompartmental septum isolating the extensor pollicis brevis (EPB) has been reported to affect the patient's response to nonsurgical treatment in de Quervain's disease. A simple physical test called the modified staged Finkelstein test was developed to evaluate the septum; the result of this test was compared with those of the pre-existing physical test (EPB entrapment test) and ultrasonographic (US) examination of the septum. Methods: We retrospectively analyzed 52 patients who underwent two clinical tests, including the modified staged Finkelstein test and the EPB entrapment test, and US examination for de Quervain's disease. The correlation between the clinical test results and US findings was evaluated; sensitivity, specificity, and positive and negative predictive values were calculated. Results: The proportion of wrists with a separate septum was 50% (26 patients) in the US examination. The sensitivity and specificity of the modified staged Finkelstein test were 88.5% and 73.1%, respectively; those of EPB entrapment test were 71.4% and 84.2%, respectively. The positive and negative predictive values of the modified staged Finkelstein test were 76.7% and 86.4%, respectively. Conclusions: The modified staged Finkelstein test showed acceptable diagnostic values for the diagnosis of septum compared with pre-existing physical tests. Knowledge about the existence of septum could be helpful in treating patients and expecting prognosis.