(Fig 4-A.18) Patellar Height Measurements: Part 2

https://youtu.be/zzE-vMhVtP4

https://youtu.be/vzxclU_34OI?si=B88NykUJHSELzyAC

 

==============================================

🎥 Check Out All Videos at Once! 📺

👉 Visit Visualizing MSK Blog to explore a wide range of videos! 🩻

https://visualizingmsk.blogspot.com/?view=magazine

📚 You can also find them on MSK MRI Blog and Naver Blog! 📖

https://mskmri.tistory.com/

https://blog.naver.com/mskmri

https://www.instagram.com/msk_mri/

Click now to stay updated with the latest content! 🔍✨

==============================================

📌Five PFI Indices for Assessing Patellar Height

1️⃣ Insall–Salvati Index (ISI)

• Description: Ratio of patellar tendon length to patella length.
• Normal Range: 0.8 to 1.2.
• Abnormal Values: <0.8 (patella baja), >1.2 (patella alta).
• Notes: Morphological variations can affect accuracy.

 

2️⃣ Modified Insall–Salvati Index (MISI)

• Description: Ratio of the distance from patellar tendon insertion to the distal end of patellar cartilage and the length of the patellar articular surface.
• Cut-off Value: 2.
• Advantage: More sensitive to patellar morphology.
• Disadvantage: Difficulty in identifying the distal end of the patellar articular surface.

 

3️⃣ Caton–Deschamps Index (CDI)

• Description: Ratio of the distance from the upper limit of the tibia to the distal end of the patellar cartilage and the length of the patellar articular surface.
• Normal Range: 0.6 to 1.2.
• Abnormal Values: <0.6 (patella baja), >1.2 (patella alta).
• Notes: Useful in various knee flexion degrees; challenges in osteoarthritic knees.

 

4️⃣ Blackburne–Peel Index (BPI)

• Description: Ratio of the perpendicular distance from the tibial plateau line to the inferior margin of the patellar cartilage and the length of the patellar articular surface.
• Normal Value: 0.8.
• Abnormal Values: >1.0 (patella alta), <0.5 (patella baja).
• Notes: Difficult to measure in CT/MRI due to non-flat tibial plateau.

 

5️⃣ Patellotrochlear Index (PTI)

• Description: Ratio of the trochlear articular surface length to the patellar articular surface length.
• Normal Range: 12.5% to 50%.
• Abnormal Values: <12.5% (patella alta), >50% (patella baja).
• Notes: Considered accurate for functional patella height on sagittal MRI.

➡️ References:

Knee Surg Relat Res. 2023 Mar 13;35(1):7

 

"Visualizing MSK Radiology: A Practical Guide to Radiology Mastery"

© 2022 MSK MRI Jee Eun Lee All Rights Reserved.

No unauthorized reproduction, redistribution, or use for AI training.

 

#PatellarHeight, #InsallSalvatiIndex, #ModifiedInsallSalvatiIndex, #CatonDeschampsIndex, #BlackburnePeelIndex, #PatellotrochlearIndex, #Radiology, #KneeAssessment, #PatellaAlta, #PatellaBaja