Evaluation of Physical Examination Tests for Thumb Basal Joint Osteoarthritis.

BACKGROUND: We compare the ability of 3 diagnostic tests to reproduce the pain of basilar joint arthritis (BJA): the grind test, the lever test (grasping the first metacarpal just distal to the basal joint and shucking back and forth in radial and ulnar directions), and the metacarpophalangeal extension test.

METHODS: Sixty-two patients with thumb BJA were enrolled. The 3 tests were performed in a random order on both hands of each patient. Prior to testing, patients reported their typical pain level and subsequently rated their pain after each test on a 0 to 10 scale, also specifying the extent to which the test reproduced their thumb pain (fully, partially, not at all). All patients had radiographs that displayed basal joint arthritis. A test was defined as positive for BJA if pain produced was greater than 0. Sensitivity and specificity for each test were calculated using the patients' history of pain localized to the basal joint and BJA diagnosis on radiographs as the gold standard.

RESULTS: The lever test produced the greatest level of pain and best reproduced the presenting pain. The lever test also had the highest sensitivity, high specificity, and the lowest false-negative rate. The grind test had the lowest sensitivity, highest specificity, and highest false-negative rate.

CONCLUSIONS: The lever test was the diagnostic test that best reproduced the pain caused by thumb basal joint osteoarthritis. We recommend using the lever physical examination test when evaluating the patient with suspected basal joint osteoarthritis. The often-quoted grind test is of limited diagnostic value.