Hip
Pediatric / Congenital
Evidence: suggestive
Telescoping Sign (Piston Test) Special Test
Orthopedic Physical Examination & Clinical Assessment Guide
What is it used for?
- Detecting a dislocated hip in a child (DDH).
How to Perform
- Position: Child lies supine with the hip and knee flexed to 90°.
- Action: Examiner grasps the thigh and pushes down (posteriorly) and pulls up (anteriorly).
Interpretation of Results
- Positive Test: Excessive movement (pistoning) of the thigh relative to the pelvis, indicating the femoral head is not seated in the acetabulum.
Clinical Context & Limitations
The Telescoping Sign (Piston Test) 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 Hip region, combining the Telescoping Sign (Piston Test) with complementary examination tests significantly improves overall diagnostic confidence.
References
- Magee, D. J. (2021). Orthopedic Physical Assessment.
