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Physical Examination for Patellofemoral Instability.

Anthony J Ignozzi¹, Matthew A Oley¹, David R Diduch¹

¹Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia, USA.

Video Journal of Sports Medicine

|October 20, 2025

Summary

This summary is machine-generated.

Physical examination is key for diagnosing patellofemoral instability. Specific tests like the apprehension and J-sign help identify hypermobility and guide surgical planning for knee instability.

Keywords:

jumping J sign moving apprehension test patellar instability patellofemoral instability trochleoplasty

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Area of Science:

Orthopedic Surgery
Sports Medicine
Diagnostic Imaging

Background:

Patellofemoral instability is a common condition, particularly in young athletes.
Accurate diagnosis relies on a combination of patient history, physical examination, and imaging.
Understanding key physical examination findings is crucial for effective management.

Purpose of the Study:

To illustrate critical physical examination findings in patients presenting with patellofemoral instability.
To demonstrate how these findings inform operative planning for knee instability.

Main Methods:

Case study approach using two distinct patient examples (soccer player, skydiver).
Detailed description of physical examination techniques: patellar glide, moving apprehension test, and jumping J sign.
Correlation of examination findings with subsequent surgical interventions.

Main Results:

Both patients exhibited positive effusion, tenderness, apprehension, and patellar tilt.
Case 1 showed a 2-quadrant lateral patellar shift and a soft J-sign.
Case 2 presented with a more pronounced instability, including a 4-quadrant lateral shift and a prominent jumping J sign.

Conclusions:

Physical examination findings are essential for operative planning in patellofemoral instability.
Specific tests like the apprehension and J-sign aid in differentiating instability from other knee pain causes.
Tailored surgical approaches, including osteotomy and ligament reconstruction, are based on detailed physical assessment.