I saw a middle aged lady last week who came in for an ultrasound scan of the wrist. She complained of radial wrist pain reminiscent of a De Quervain’s syndrome. However the symptoms were somewhat different. The main area of pain was 4 cm proximal of the radial styloid process. Resisted testing was more painful on extension but was not worse when adding ulnar deviation which is usually the case with De Quervain’s tenosynovitis.
Finkelstein’s test was only mildly positive. Ultrasound revealed some tenosynovitis of the extensor pollicis brevis at the radial styloid. When moving proximal with the US probe transverse to 1st extensor compartment the tenosynovitis became more pronounced where the EPB crossed of the second compartment. The APL seemed to be relatively unaffected (more clearly seen on video please see link above) This syndrome has been described as Intersection syndrome of the wrist. The few articles that I could find on intersection syndrome very much supported my clinical- and ultrasound findings.
I have clinically diagnosed this syndrome several times however on previous occasions there was no sign of tenosynovitis but it clinically resembled a myositis type or myo-tendinous junction syndrome with pain over the muscle rather than tendon. The severity of the symptoms correlated well with degree of tenosynovitis as seen on ultrasound.
As it seemed to be more related to the overuse/provocation of the extensor component of the 1st extensor compartment i.e the EPB rather than APL it seems sensible to focus more on avoiding repeated extension stress rather ulnar deviation stress which is the predominant complaint in De Quervains tenosynovitis.