Patellar tracking disorder

Patellar tracking disorder happens when the kneecap shifts out of its normal groove as the knee bends and straightens. This uneven movement, often called patellar maltracking, can cause knee pain, a feeling of instability and discomfort during everyday activities like climbing stairs or squatting. With an accurate diagnosis and the right treatment plan, most people find lasting relief and return to the activities they enjoy.

Find a specialist

Find a location

Illustration of the knee showing the patella, patellar ligament and tibial tuberosity.

Anatomy of the knee

The kneecap, or patella, sits in a groove at the end of the thighbone called the trochlear groove. As you bend and straighten your knee, the patella should glide smoothly up and down this groove, guided by surrounding muscles, tendons and ligaments.

When something disrupts this balance, the kneecap can shift too far to one side, usually toward the outside of the knee. This is patellar tracking disorder. Over time, this uneven movement can irritate the cartilage under the kneecap and put extra strain on the soft tissues that hold the patella in place.

Overview

Symptoms

Patellar tracking disorder can cause a range of symptoms that often worsen with activity. Common signs include:

Pain in the front of the knee, especially around or under the kneecap
A feeling that the kneecap is slipping, shifting or catching
Popping, grinding or clicking sounds with movement
Swelling around the knee
Weakness or a sense of the knee giving out
Discomfort when climbing stairs, squatting or sitting for long periods

Symptoms may start mild and gradually become more noticeable, particularly with repeated bending or high-impact activity.

Causes

Patellar tracking disorder develops when the forces acting on the kneecap become unbalanced, causing it to pull to one side instead of gliding straight. Common contributing causes include:

Muscle imbalances, particularly weakness in the inner thigh muscles
Tightness in the outer knee structures that pull the kneecap off center
Structural differences in the shape of the kneecap or the trochlear groove
Alignment issues in the hips, knees or feet
Previous injury to the knee

In some cases, more than one factor contributes, and the exact cause can be difficult to pinpoint.

Risk factors

Certain factors may increase the likelihood of developing patellar tracking disorder. Having one or more of these does not mean you will develop the condition. Risk factors include:

Participation in sports that involve running, jumping or repetitive knee bending
Naturally shallow trochlear groove or unusually shaped kneecap
Muscle weakness or imbalance around the hip and thigh
Previous knee injury or kneecap dislocation
Flat feet or other lower limb alignment differences

Diagnosis

Diagnosing patellar tracking disorder starts with a discussion of your symptoms and a physical exam to assess how your kneecap moves as you bend and straighten your knee. Your care team will check for tenderness, swelling, alignment and muscle strength around the knee.

Imaging tests can help confirm the diagnosis and identify contributing factors. These may include:

X-rays, which show the position and alignment of the kneecap
MRI, which provides detailed images of cartilage, tendons and ligaments
CT scan, which can offer a closer look at bone structure and alignment in more complex cases

View treatment options

We offer leading-edge treatments for most joint medicine conditions, treating many with medications, bracing, injections and therapy.

Explore treatments

Is joint pain holding you back?

It only takes a few minutes to help you stay active for years. Our joint health quiz shows you how to stay strong, flexible and moving freely through every stage of life.