Stenosing Tenosynovitis of the Extensor Carpi Ulnaris: A Reverse De Quervain Tenosynovitis

Purpose or Learning Objective: The extensor carpi ulnaris (ECU) can be the site of a rare and probably underestimated tendinopathy: stenosing tenosynovitis. We observed several cases of stenosing tenosynovitis of the ECU with an epicenter located distal to the ulnar groove and styloid, at the level of the ulnocarpal joint, by thickening of the extensor retinaculum.

The main objectives of our study were to confirm the existence of stenosing tenosynovitis of the ECU, to describe the ultrasonography (US) signs, and to determine the area of conflict. Our secondary objectives were to find circumstances leading to this type of tendinopathy and to propose a new option for US-guided treatment.

Methods or Background: Our case-control study compared a retrospective series of 30 pathologic US findings of patients with ulnar-sided wrist pain associated with compartment VI retinaculum thickening, with 31 healthy volunteers who were evaluated by two radiologists (one senior and one junior radiologist) in a double-blind procedure.

A set of qualitative (presence or not of Doppler hyperemia, intratendinous fissure, tendon instability, anisotropy artifact, anatomical variations) and quantitative (thickness of the ECU tendon and its retinaculum at multiple section levels) variables were compared.

Results or Findings: Several signs were found only in certain cases: pain at passage of the probe (100% [30/30]), Doppler hyperemia (80% [24/30]), tendon anisotropy artifact (56.7% [17/30]), and intratendinous fissure (16.7% [17/30]).

The mean retinacular thickness in both cases and controls was greater at the level of the ulnocarpal joint (1.893 mm and 0.858 mm, respectively). This thickness was significantly greater in the pathologic cases in our series (p < 0.001).

The receiver operating characteristic (ROC) curve for this retinacular thickness gave a sensitivity of 93.33% and a specificity of 100% for a cutoff of 1.3 mm.

Conclusion: Our retrospective US series based on 30 patients allowed us, by comparison with a sample of 62 wrists of 31 healthy volunteers, to review a poorly known pathology: stenosing tenosynovitis of the ECU. Maximum thickening of the ECU tendon and its retinaculum was observed at the level of the ulnocarpal joint. A thickening > 1.3 mm at this level allows the diagnosis to be made with excellent sensitivity and specificity.

Publication History

Article published online:
02 June 2022