Clinical measurement.
Common provocative maneuvers to differentiate thumb carpometacarpal (CMC) osteoarthritis from other sources of pain are the grind, metacarpal (MC) flexion, and MC extension tests. A maneuver known as the pressure-shear test is described here.
To compare the diagnostic value of the grind, metacarpal flexion, metacarpal extension, and pressure-shear tests for CMC osteoarthritis of the thumb.
The diagnostic accuracy of each test was compared in 127 thumbs from 104 patients. Sensitivity, specificity, and predictive values of each test were calculated. In a secondary analysis, polychoric correlation coefficients were used to assess the correlation of each test with severity defined by Eaton-Littler stage.
The overall diagnostic accuracy of the thumb MC grind, pressure-shear, flexion, and extension tests were 70%, 98%, 47%, and 55%, respectively. The sensitivities were 64%, 99%, 36%, and 46%, respectively, and specificities were 100%, 95%, 100%, and 100%, respectively. For the diagnosis of Thumb CMC arthritis, the MC pressure-shear test was superior overall in terms of overall diagnostic accuracy and sensitivity, while having comparable specificity to the other maneuvers.
The pressure-shear test was found to be superior to the commonly used grind maneuver and the provocative maneuvers of MC flexion and extension tests to confirm diagnosis of CMC osteoarthritis.