Sonographic findings of extensor digiti minimi triggering caused by thickened extensor retinaculum

Abstract

Trigger finger is a common well recognized condition and involves the flexor tendons at the A1 pulley in the palm. Triggering of the extensor tendons is a very rare clinical entity. We report a rare case of extensor triggering of little finger caused by constriction of the extensor digiti minimi by a markedly thickened extensor retinaculum (ER) at the wrist, well delineated dynamically by real-time high-resolution ultrasound. The patient underwent release of thickened ER and was asymptomatic immediately.Keywords Extensor Á Tendon Á Trigger Á Retinaculum Á Ultrasound Sommario Il dito a scatto è una condizione frequente, ben riconosciuta, che coinvolge i tendini flessori a livello della puleggia A1. A livello dei tendini estensori è un'entith clinica molto rara. Riportiamo un raro caso di dito a scatto dell'estensore del mignolo causato da un marcato ispessimento del retinacolo degli estensori (ER) a livello del polso, ben evidenziato con ecografia dinamicamente ad alta risoluzione. Il paziente è stato sottoposto a intervento con resezione dell'ER ispessito con conseguente, completa, risoluzione della patologia.

EURO-MUSCULUS/USPRM Dynamic Ultrasound Protocols for Wrist and Hand

“…2 and Video 13, http://links.lww.com/PHM/B609). In some cases, the thickened retinaculum can mimic trigger finger symptoms whereby dynamic US examination would definitely be contributory 15,16 . Similar to other conditions, if a mass or bone fragment is present at this location, dynamic scanning can also explain the exact causal relationship between the pathology and the patient’s complaint.…”

Acquired triggering of the fingers and thumb in adults

“…Occasionally, triggering can be confused with extensor tendon pathology or arthritis. 19 Two observational studies looking at diabetic populations provide good evidence that incidence of trigger digits is between 5% 20 (n=250, <40 years old) and 10% 21 (n=544, >50 years old). Poor glycaemic control with glycated haemoglobin over 7% is a good predictor of symptomatic disease.…”

Tendinosis in Trigger Finger

“…There could be an infection as tuberculosis 17 , a side effect of anti-oestrogens (letrozole and exemestane) 134 or an effect of acromegaly 135 . There might be an exostosis 136 or a soft tissue tumour, either in the tendon sheath 120 or in the tendon 137,138 , at the level of the wrist 139,140 , on the dorsum of the hand 141 or both 142 . It can trigger due to a chondroma 143 , leiomyoma 144,145 , granuloma 146 , or fibroma 147 .…”