Why Do My Knees Sound Like Rice Krispies? Diagnoses + When To See A Doctor

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reviewed by Katelyn Tocci

Have you ever been moving about your day, perhaps bending or squatting down, and found yourself asking, “Why do my knees sound like Rice Krispies?“

Knees sounding like Rice Krispies is a common description for creaky knees, crunchy knees, or knees cracking.

Much like the tagline (and mascots) of the popular Rice Krispies breakfast cereal—snap, crackle, and pop—describe the popping or crunchy sound that happens when you add milk to your bowl of Rice Krispies cereal, some people have knees that exhibit a popping, crunching, or snapping sound or sensation.

But, what causes knee crunching and cracking when bending and moving? What makes your knees sound like Rice Krispies cereal?

In this article, we will discuss the underlying causes of crunchy knees, creaky knees, or knee cracks when bending, squatting, walking, or moving, whether knee crunching is concerning, and ultimately answer your question, why do my knees sound like Rice Krispies?

We will look at: 

  • Why Do My Knees Sound Like Rice Krispies?
  • What Is Knee Crepitus?
  • Is It Bad If My Knees Sound Like Rice Krispies?
  • How to Stop Knees Cracking and Popping

Let’s get started!

A person holding their knee.

Why Do My Knees Sound Like Rice Krispies?

When people describe their knees sounding or feeling like there are Rice Krispies in them, they are referring to an audible or palpable feeling of popping, crunching, snapping, or creaking when they get up, bend their knees, climb or descend stairs, walk, run, jump, etc.

Although we use laymen’s terms like crunchy knees or creaky knees, the medical condition that people are often describing when experiencing this phenomenon is called knee crepitus.

Occasional knee popping can also occur when the kneecap snaps in and out of its groove based on the way that the patellar tendon and quadriceps muscles are pulling on the embedded patella (the kneecap).

However, if you have a chronic feeling of crunchy knees, grinding knees, or Rice Krispies knees, it’s more likely a case of knee crepitus.

A person holding their knee.

What Is Knee Crepitus?

When your knee sounds like Rice Krispies crackling and popping, or you feel a grinding or crunching sensation when you move your knee, it often means you have knee crepitus.

Knee crepitus can be an early sign of knee osteoarthritis developing behind the kneecap, where it sits on top of the end of the femur (thigh bone) and tibia plateau (shin bone).

Knee osteoarthritis is a degenerative condition, which means that it develops due to wear and tear on the knee joint over time.

Although there can be a number of causes of knee crepitus, it is mainly caused by patellofemoral dysfunction, which refers to an issue in proper tracking of the kneecap along the patellar groove.

The kneecap, which is known as the patella bone, is embedded in a very thick tendon that serves as the confluence of the tendinous ends and of the four quadriceps muscles.

This thick patella tendon is where the muscle bellies of each of the quadriceps muscles end, and the tendon fuses the muscles to the very top of the tibia below your knee joint.

A person holding their knee.

In many ways, the patella can be described as “floating” in the knee joint in the sense that it isn’t directly sandwiched between other bones but rather overlying the joint interface between the femur and tibia.

Instead, there is cartilage on the back of your knee and cartilage on the front part of the very bottom of the femur or thigh bone.

The cartilage at the end of the femur has a groove in which the kneecap is intended to slide up and down as you bend and straighten your knee.

If the cartilage becomes inflamed or worn down over time (which is what occurs with knee osteoarthritis), the integrity of this patellar groove is compromised. 

This can cause the kneecap to track out of the groove or no longer glide smoothly up and down. This can cause a popping or grinding sensation in your knee.

Note that once the cartilage has become so worn down or frayed in certain areas, such that you have knee osteoarthritis, you will likely have pain accompanied by the knee crackling and popping.

A doctor holding a knee model and pointing to the joint.

This is because he will have some bone-on-bone rubbing where the back of the patella bone is scraping along the front and bottom portion of the femur.

Unlike cartilage, which is smooth and lubricated with synovial fluid, which acts sort of like motor oil in a car, when the bones rub together, there is a lot of friction and pain.

It’s also important to note that it’s possible to have patella tracking issues if you have muscle imbalances in your hips and quadriceps.

Particularly when comparing the strength of the vastus lateralis, which is on the outer portion of the quadriceps, versus the vastus medialis which is on the inner side of the quads, any disparity in the strength in these muscles can contribute to issues with the patella tracking properly in the groove.

If one of these muscles is stronger or overactive relative to the other, it can pull the patella in that direction, causing the kneecap to migrate out of the groove somewhat when you bend and straighten your leg.

This can contribute to injuries such as runner’s knee and can eventually cause premature breakdown of the cartilage, leading to knee crepitus and then knee osteoarthritis.

A doctor holding a patient's knee.

Is It Bad If My Knees Sound Like Rice Krispies?

Occasional crackling knees or knee creaking when bending and squatting is normal and is generally not a cause for concern, particularly if the sensation is not accompanied by pain or discomfort.

However, if your crunchy knees seem to be developing into a chronic condition rather than an occasional problem, it is imperative to consider seeing a physical therapist to help correct any potential muscle imbalances or movement problems that are contributing to patellar malalignment issues.

As mentioned, patellar malalignment can progress to knee osteoarthritis.

If you are experiencing any type of pain with your crunchy knees or creaky knees, you should speak with your doctor or physical therapist before the knee crepitus worsens and becomes full-blown knee osteoarthritis.

Knee osteoarthritis is degenerative, so it will typically not heal on its own.

There are pain management strategies such as strengthening the surrounding muscles to reduce the forces on the knee joint as well as injections of synthetic synovial fluid to help lubricate the joint. 

Minor arthroscopic surgery, called debridement, can also help clean up any frayed cartilage to smooth rough edges and promote better gliding of the kneecap in the knee joint. 

The end result treatment for severe knee osteoarthritis is a total knee arthroplasty, which is the technical term for a knee replacement surgery.

A physical therapist helping a patient with their knee.

How to Stop Knees Cracking and Popping

Depending on the cause of the crepitus, it may or may not be possible to do much to stop your knees from sounding like there are Rice Krispies in your knee joint.

As a quick summary, some of the common causes of knee crepitus include the following:

  • Knee osteoarthritis
  • Patella femoral syndrome
  • A prior injury such as meniscus tears, runner’s knee, IT band syndrome 
  • Patellar tracking problems
  • Ligaments or tendons moving or “snapping” around the knee joint
  • Fluid or gas bubbles in your knee joint

Here are some of the potential treatment strategies for knee popping, crunching, and crackling:

A physical therapist helping a patient with their knee.
  • Physical therapy to help correct muscle imbalances that are leading to patellar tracking issues or prior injuries.
  • Synthetic synovial fluid injections or surgery to deal with knee osteoarthritis.
  • Consistent, periodic stretching, walking around, and bending and straightening your knee to move knee joint fluid around and pop gas bubbles within the knee joint capsule.
  • Weight management in cases where excess body weight is causing additional stress on your knee joint.
  • Low-impact exercise such as swimming, elliptical machine, indoor cycling workouts, outdoor biking, incline walking, tai chi, deep water running, and rowing to help strengthen the muscles surrounding the knee joint, improve your fitness, and support healthy weight management, all while decreasing impact stress and compression on the knee joint with high-impact exercises like running, jumping, jump roping, and plyometrics.
  • Prescription anti-inflammatories, if recommended by your doctor.
  • Following an anti-inflammatory diet with foods like fatty fish, omega-3 fish oil supplements, nuts and seeds, green leafy vegetables, tart cherry juice, turmeric or curcumin supplements, and fruits and vegetables rich in antioxidants.
  • Working with a personal trainer or fitness professional to improve your exercise form and technique, particularly for exercises that load the knee, such as squats, lunges, box jumps, and other foundational strength training movement patterns.
  • Improving your running form if you are a habitual runner and running is exacerbating knee clicking and popping.
  • Wearing supportive footwear at all times.

To learn more about common knee injuries, check out our guide about knee injuries from running here.

A runner bending down on the road holding their knee.
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Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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