Internal Rotation Resistance Stress Test (IRRST) Special Test
Orthopedic Physical Examination & Clinical Assessment Guide
What is it used for?
- Differentiating Internal Impingement from Outlet Impingement.
How to Perform
- Position: Abducted 90°, Externally Rotated 80°.
- Action: Compare strength in External Rotation vs Internal Rotation.
Interpretation of Results
- Internal Impingement: Weakness in Internal Rotation.
- Outlet Impingement: Weakness in External Rotation.
Diagnostic Accuracy
- Sensitivity: 88%
- Specificity: 96%
Clinical Context & Limitations
The Internal Rotation Resistance Stress Test (IRRST) 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 Shoulder region, combining the Internal Rotation Resistance Stress Test (IRRST) with complementary examination tests significantly improves overall diagnostic confidence.
References
- Magee, D. J. (2021). Orthopedic Physical Assessment.
