Tendon
disorders
Trigger
finger
For reasons which are often obscure, the opening of the flexor tendon
sheath (the Al pulley) thickens and snares the tendon which may secondarily
develop a small nodule. When the proximal interphalangeal joint is flexed it locks
and then snaps into extension. This often starts only on awakening, and then
gradually occurs more frequently during the day. If it does not resolve with a
steroid injection into the sheath, then release of the pulley at the level of
the metacarpophalangeal joint (distal palmar crease) is successful, watching for
the neurovascular bundle. In infants, the thumb can trigger; this often resolves
spontaneously by the age of 1 year, but if not surgery is needed, being aware
that in the thumb the digital nerves run close to the midline (not the
midlateral line as they run in the fingers). In rheumatoid arthritis, the
triggering is caused either by synovitis or by a nodule in the tendon.
Synovectomy, and if necessary excision of a slip of flexor digitorum
superficialis, is safer than division of the pulley — the latter can worsen
the tendency to ulnar drift of the metacarpophalangeal joints.
De
Quervain’s disease
The extensor pollicis brevis tendon and abductor pollicis longus tendon
run in a compartment beneath the extensor retinaculum. This compartment can
constrict the tendons, causing pain at the base of the thumb. Usually occurring
spontaneously in middle-aged women, it is also associated with late
pregnancy and overuse. Finkelstein’s test is positive