Glossary
Patella (kneecap)
Quick answer
The patella, or kneecap, is a small triangular bone set inside the tendon at the front of the knee. It acts as a lever that makes the quadriceps more efficient when you straighten the leg, and it protects the joint, as Doha knee surgeon Dr. Pablo Gelber explains to patients at Aman Hospital.
What it is
The patella sits within the extensor mechanism: the quadriceps tendon attaches to its top and the patellar tendon runs from its lower tip to the tibia. Its back surface is covered with some of the thickest cartilage in the body and glides up and down in the trochlear groove of the femur as the knee bends.
By holding the tendon away from the joint, the patella increases the leverage of the thigh muscles. Forces across the kneecap are high on stairs, squats and kneeling.
Why it matters for patients
Problems with the kneecap are a leading cause of pain at the front of the knee, especially in teenagers, runners and people who squat or kneel a lot. The kneecap can slip out of its groove (patellar dislocation), particularly in young people with a shallow groove or loose ligaments. Its cartilage can soften (chondromalacia patella) or wear in arthritis, and a direct fall onto the knee can fracture it.
How it is examined
A surgeon watches how the kneecap tracks as you bend and straighten, presses around it and checks how far it can be pushed sideways. Special X-ray views and MRI show its position, cartilage and the groove it runs in.
Frequently asked questions
Why does my kneecap hurt on the stairs?
Stairs and squats press the kneecap hard against the femur. Irritation of the cartilage or surrounding tissue often shows up first on stairs, after sitting for a long time, or when kneeling.
Can you live without a kneecap?
It is very rarely removed today. Without it the thigh muscles lose leverage, so surgeons repair or preserve the patella whenever possible.
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