Execution
- 1Position the patient sitting with the hand on a stable surface.
- 2Stabilize the hand with the wrist and metacarpals in neutral.
- 3Grasp the first metacarpal.
- 4Move the first metacarpal into extension at the CMC joint.
- 5Record whether basal thumb pain is reproduced.
Positive outcome
Pain in the basal region of the thumb during first metacarpal extension is positive. Any pain should be localized to the CMC joint region rather than the MCP joint. The test is designed as a provocation for thumb CMC OA.
Studies
| Study | Reliability | Sn | Sp | LR+ | LR− |
|---|---|---|---|---|---|
| Sela et al. (2019) | NA | 46 | 100 | infinity | 0.54 |
CommentSela found perfect specificity but low sensitivity for the MC extension test. The infinite LR+ is mathematically produced by 100% specificity and should be read cautiously, especially because diagnostic performance was evaluated in one study. A negative test does not rule out CMC OA.
High Clinical Value