What is the Insall-Salvati ratio?

The ratio of patellar tendon length to patellar length measured on lateral X-ray. Normal: 0.8-1.2. Ratio greater than 1.2 = patella alta (high-riding patella) associated with instability and anterior knee pain in flexion.

How does patella alta affect knee pain?

Patella alta reduces patellofemoral contact area at early flexion, increasing contact stress per unit area. This can cause anterior knee pain during activities like stair climbing and squatting.

Patellofemoral Pain Knee Height Insall-Salvati Ratio Calculator

Calculate Insall-Salvati ratio for patellar height assessment. Ratio = patella tendon length divided by patella length. Patella alta: ratio greater than 1.2; patella baja: less than 0.8. Affects patellofemoral contact area and pain.

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How to Use

Enter the values for the scenario you are assessing. Calculate Insall-Salvati ratio for patellar height assessment. Ratio = patella tendon length divided by patella length. Patella alta: ratio greater than 1.2; patella baja: less than 0.8. Affects patellofemoral contact area and pain. Use the patella alta ratio result to inform your calculation.

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Patellofemoral Pain Knee Height Insall-Salvati Ratio Calculator

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Frequently Asked Questions

What is the Insall-Salvati ratio?

How does patella alta affect knee pain?