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Patellar J Sign

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Patellar J Sign
Demonstration of the normal patella J sign[1]
Patellar J Sign[2]
Clinical photograph showing the knee in flexion (A) and in extension (B). The dotted line delineates the inverted ‘J’ path the patella takes.[3]
  • J-sign
  • Patellar J-sign
  • Inverted J sign
  • J-sign test
  • J Sign
  • Knee J Sign
  • Patellar Tracking J Sign
  • Lateral Patellar Tracking Sign
  • Patellar Maltracking Sign
  • J Curve Sign (less commonly used)

Purpose

Description

  • Patient is seated with leg hanging off examination table
  • Patient is asked to bring knee into full extension and then passively flex to 90° or more
  • Abnormal
    • Laterally tracking patella suddenly shifts medially as it engages the trochlear groove of the distal Femur

Pathology

Evidence

  • Needs to be updated

See Also

References

  1. ↑ D’Ambrosi, Riccardo, et al. "Anterior knee pain: state of the art." Sports Medicine-Open 8.1 (2022): 98.
  2. ↑ Rosa, Sergio Barroso, et al. "Dynamic evaluation of patellofemoral instability: a clinical reality or just a research field? A literature review." Orthopaedic surgery 11.6 (2019): 932-942.
  3. ↑ Ibad, Hamza Ahmed, et al. "Computed tomography: state-of-the-art advancements in musculoskeletal imaging." Investigative radiology 58.1 (2023): 99-110.
Created by:
John Kiel on 26 October 2020 00:01:54
Authors:
Last edited:
8 April 2026 14:33:28
Categories:
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