De Quervain Tenosynovitis: MRI

34 yrs male with chronic right thumb pain / no trauma / X ray unremarkable for MRI right hand, shows -Diffuse subcutaneous edema on radial  aspect of lower third of forearm / wrist /proximal hand regions with significant free fluid along the tendons of first extensor compartment ( Abductor pollicis longus – APL & Extensor pollicis brevis – EPB) with relative more involvement of APL than EPB with ill definition & enlargement of tendons including insertional sites ( APL sips to trapezium/base of 1^st metacarpal & EPB  to base of proximal phalanx of thumb) with no significant radial styloid abnormality – possibly suggesting De Quervain tenosynovitis. Subtle edema /tiny cyst in lunate (contour & intercarpal articulations maintained) with subtle heterogeneity of the triangular fibrocartilage complex ligament with rest grossly normal – possibly represent stress related change. Case Report submitted by Dr GA Prasad & Dr MGK Murthy

Discussion –

Clinically – h/o of repetitive overuse and sustained thumb abduction and extension in combination with radial and ulnar wrist movements in the dominant hand as usually seen in workplace activities / carrying babies/ sports related  with associated soft tissue swelling in the radial side of wrist.

Classic de Quervain’s tenosynovitis includes chronic inflammation scar formation with stenosis of the approximately 1-cm-long fibroosseous tunnel of the first dorsal compartment (the groove along the radial styloid process covered by the overlying extensor retinaculum through which the abductor pollicis longus and extensor pollicis brevis tendons run). Histological examination of the disease reveals myxoid degeneration within the tendon sheath wall with degeneration as the primary process rather than inflammation within the tendon sheath.

Typical  MRI findings de Quervain’s tenosynovitis are soft-tissue enlargement in the region of the first compartment of the wrist, thickening of the tendon sheath with decreased signal intensity on both T1- and T2-weighting, bone spurring at the site of attachment of the overlying extensor retinaculum .

MRI can help in prognostication & guiding management by providing information about –

-          Number of slips of each tendon,

-          Presence of any intervening septum &

-          Relative severity of involvement of each tendon separately.

These findings may be predisposing conditions for the disease & may cause surgical or percutaneous treatment to fail.

Multiple tendon slips have variable insertions and cause increased friction, predisposing to tenosynovitis with “lotus root” appearance on ultrasound with tendon slips appearing as holes in the sliced lotus root.

Multiple slips are more common in APL than EPB tendons. Information about multiple APL tendons is also relevant for surgical procedures in patients with degenerative joint disease and chronic subluxation of the first carpometacarpal joint. Presence of a septum may split the first extensor compartment into subcompartments partially or completely. This anatomic variation is common in de Quervain tenosynovitis with poor response to both medical and operative management . Failure to inject steroid into or surgically decompress both the subcompartments may lead to persistent symptoms. In the presence of an intervening septum, the EPB tendon is usually more severely affected than the APL tendon. The septum is much easier to visualize on ultrasound & MRI may suggest its presence indirectly by involvement of only one of the tendons. Other indirect indicators of subcompartmentalization include a bony ridge and double groove on the surface of the radial floor.

Radiologic differentials  -  include atypical infections, scaphoid fracture or nonunions or radioscaphoid arthritis, and trapeziometacarpal joint arthritis where bony findings help in diagnosis. Rheumatoid arthritis can be another cause of stenosing tenosynovitis of the wrist.

Clinically, flexor carpi radialis tenosynovitis entrapment of the branches of the superficial radial nerve can mimic de Quervain’s disease.

Another rare differential diagnosis, both clinically and radiologically, is the intersection syndrome . Pain and swelling of the muscle bellies of abductor pollicis longus and extensor pollicis brevis 4 cm proximal to the wrist joint and the disorder location are probably caused by tenosynovitis of the second dorsal compartment of the wrist.