(Fig 4-A.19) Patellar Tilt Angle

https://youtu.be/wv8NtsC09d0

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

 

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📌 Patellar Tilt Angle (PTA)

• The Patellar Tilt Angle (PTA) is a critical measurement used to assess the patellar tilt. To measure the PTA, the angle between the tangential line to the posterior aspect of both femoral condyles and the line passing through the longest axis of the patella is determined. 
• This measurement is commonly performed on axial CT and MR images.

 

✅ Measurement Technique:

1. Identify the tangential line to the posterior aspect of the femoral condyles.
2. Draw a line through the longest axis of the patella.
3. Measure the angle between these two lines.

 

✅ Clinical Significance:

• An increased PTA can indicate patellofemoral instability or excessive lateral pressure syndrome. 
• A PTA greater than 20° is generally considered pathological, particularly when the quadriceps muscle is relaxed.

 

1️⃣ Transient Lateral Patellar Dislocation:

• Characterized by lateral patellar tilt and lateral translocation without actual dislocation.
• PTA is significantly increased, reflecting the instability of the patella.

 

2️⃣ Excessive Lateral Pressure Syndrome (ELPS):

• Marked by anterior knee pain and lateral patellar tilt without subluxation.
• MRI is the preferred imaging modality.
• Imaging findings include lateral patella facet chondromalacia, lateral osteophytes, and thickening of the lateral retinaculum.
• Early evidence includes abnormal tilting without lateral subluxation.

 

➡️ References:

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

Radiographics. 2023 Jun;43(6):e220177

Skeletal Radiology (2019) 48:859–869

 

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#PatellarTiltAngle, #PTA, #KneeInstability, #PatellofemoralInstability, #OrthopedicImaging, #KneePain, #MRI, #CTScan, #ExcessiveLateralPressure