The extensor pollicis brevis entrapment test in the treatment of de Quervain's disease.

Isolation of the extensor pollicis brevis (EPB) tendon in a separate compartment has been reported to contribute to the pathogenesis of de Quervain's disease and affect the patient's response to nonsurgical treatment. The EPB entrapment test was developed to evaluate the patient with de Quervain's disease. The purpose of this study was to compare the results from this preoperative test with the anatomic findings at surgery in patients who failed nonsurgical treatment. One hundred seventy-eight patients who were treated for de Quervain's disease (200 wrists) were asked to compare the amount of pain elicited by firm resistance with thumb metacarpophalangeal joint extension with that from resistance to palmar abduction. Twenty-six wrists (13%) had surgical release after failure of nonsurgical treatment. Of those having surgery the proportion of wrists with a positive EPB entrapment test was significantly higher among those with 2 compartments (18 of 22) than among those with 1 compartment (0 of 4) (Fisher's exact test). In the surgical group the EPB entrapment test showed 81% sensitivity and 50% specificity in identifying wrists with a separate EPB compartment.