Patellar alignment

Written by Dr Sheila Strover on March 14, 2025

Patellar alignment is the position of the kneecap relative to the groove in the underlying femur bone into which it slides when the knee is bent and straightened.

Normal Patellar Alignment

Normally the articular cartilage at the back of the patella aligns perfectly with the articular cartilage in the underlying trochlea, which is a nice V-shape.

The patella is normally held in this position by restraints from:

the lateral side - lateral retinaculum
the medial side - medial patellofemoral ligament (MPFL)
below - the patellar tendon attached to the tibia bone via the tibial tubercle
above - the quadriceps tendon of the quadriceps muscle which attaches at several places to the femur bone
obliquely above - the vastus medialis obliquus part of the quadriceps muscle
obliquely below - the medial and lateral retinacula

Illustration of a skyline view of the patella, showing how it snugs into the underlying trochlear groove.

What factors cause patellar malalignment?

Abnormal patellar alignment may affected by structural abnormality of the patella or trochlea, such as -

or by abnormal tension on the patella from other structures:

Tight lateral retinaculum
Tibial tubercle in poor alignment
Torsion of femur or tibia
Weak MPFL
Weak quadriceps, especially VMO

Illustration of a side view of the attachment of the patellar tendon, showing the situation of the patellar bone within the tendon.

Other relevant links on KNEEguru

A-Z Keywords

Patella, Patellar tracking, Patellofemoral pain syndrome, Patellofemoral syndrome

Primer - 2017 - The Patella - A Primer

Contributions by experts -

Dr Lee Herrington - 2013 - Why does my kneecap hurt?

Video - What is the patella?