Wrist & Hand
Instability
Evidence: uncertain
Piano Key Sign Special Test
Orthopedic Physical Examination & Clinical Assessment Guide
What is it used for?
- Diagnosing Distal Radioulnar Joint (DRUJ) Instability.
How to Perform
- Position: Hand pronated.
- Action: Examiner pushes down on the distal ulna (ulnar head) like pressing a piano key.
Interpretation of Results
- Positive Test: The ulna springs back up (ballottable) with pain or excessive movement.
Clinical Context & Limitations
The Piano Key Sign should be considered as one component of a comprehensive musculoskeletal assessment. No single special test has perfect diagnostic accuracy; thus, clinical decision-making should integrate test results with patient-reported symptoms, mechanism of injury, functional impairment, and relevant imaging.
Clinicians should be aware of potential false-positive results in patients with pain sensitisation, muscle guarding, or poor relaxation. For the Wrist & Hand region, combining the Piano Key Sign with complementary examination tests significantly improves overall diagnostic confidence.
