Ultrasound for the diagnosis of pyogenic flexor tenosynovitis.

The usefulness of ultrasound for making the diagnosis of pyogenic flexor tenosynovitis (PFTS) has been demonstrated. The primary goal of this study was to show that the diameter of the flexor sheath near the A2 pulley was larger when PFTS was present compared to the healthy contralateral finger. The secondary goal was to determine the reproducibility of these ultrasound measurements. Our series included 20 patients (12 men and 8 women) operated due to PFTS. The average age was 41.7 years old. The average diameter of the digital sheath measured near the A2 pulley on transverse and longitudinal ultrasound sections was 5.01mm (transverse 5mm, longitudinal 5.03mm) on infected fingers, and 4.17mm on healthy contralateral fingers. Reproducibility, as measured by the intraclass coefficient between transverse and longitudinal values, was 0.910 for infected fingers and 0.928 for contralateral fingers, thus was excellent. Our hypothesis was confirmed. A unilateral increase of more than 20% in diameter of the flexor sheath measured in transverse or longitudinal ultrasound sections near the pulley A2 contributes to the surgical indication when a patient presents with PFTS.