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6 Signs of Patellar Instability

6 Signs of Patellar Instability

Many people assume that the kneecap serves as a shield to protect the inner workings of the knee, and this is true, to some extent. Outside of this important role, your kneecap performs a more important one — it allows you to extend and flex your leg.

As you might imagine, when there’s a malfunction with this part of your joint, such as patellar instability, it can really throw your leg off its game.

To give you an idea about what occurs when you have patellar instability, William Schell, MD, who specializes in knee issues, outlines a few of the common signs of this condition.

Patellar instability basics

Before we explore the many ways in which patellar instability can be felt, let’s briefly review the problem.

Your knee is the largest joint in your body, and it’s where three bones come together:

  1. Tibia (shin bone)
  2. Femur (thigh bone)
  3. Patella (kneecap)

As we mentioned, your kneecap not only protects your joint, it serves as a bridge between your shin and thigh by connecting the muscles in front of your femur to the muscles in front of your tibia. This connection provides the leverage you need to extend your leg.

To make sure that your kneecap is stabilized, the end of your femur features a trochlear groove, which keeps your kneecap sliding up and down in the right position.

When you have patellar instability, your kneecap isn’t tracking inside the your trochlear groove as it should, creating a dislocation.

This type of dislocation accounts for about 3% of all knee injuries and occurs often in females between the ages of 10 and 16.

Signs of knee instability

Now that we better understand what occurs when someone develops patellar instability, let’s take a look at how you might recognize the problem.

1. Knee instability

Let’s start with an obvious symptom given the name — instability. When you have patellar instability, you might feel like your knee isn’t secure. It can buckle and not support your weight.

2. Catching in your knee

Another sign of patellar instability is catching in your knee, which occurs when your kneecap isn’t sliding through the trochlear groove properly.

3. Pain while sitting

The discomfort that’s associated with patellar instability occurs most often when you’re sitting. When your knee is at an angle, you can develop an intense pain in the front of your knee.

4. Pain with activity

In addition to pain while you’re sitting, you may also experience pain after a while when you’re on your feet and using the affected knee. This pain also develops toward the front of your knee.

5. Stiffness and swelling

Any time you have stiffness and swelling in your knee, it indicates an issue. A knee dislocation can certainly lead to these symptoms. 

6. Crackling sound in your knee

If your knee is making cracking, popping, or creaking noises, this could indicate a dislocation.


If any of these symptoms sound familiar, it’s a good idea to come to us for a full evaluation. To get started, simply contact our New York City office, which is located on Columbus Circle on the Upper West Side.

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