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Here is a full guide on what causes knee popping, possible diagnoses, and suitable treatments to solve your knee problems.

Possible Causes, Diagnosis, and Treatment

Knee popping can be a sensation that something is moving around in the knee. There may also be an audible sound associated with the popping, which in medical terms is called crepitus. This can also cause what we call mechanical catching or locking, which may make the knee feel like it is stuck in an extended or flexed position, and you have to move it in certain ways to get out of that. This knee popping sensation or sound or could be a very simple issue or it could be a sign that more serious damage is going on in the knee, so determining what is causing it is very important.

Why Do My Knees Pop? A Look Into Knee Anatomy:

knee popping anatomy

So, the knees may pop and get in a certain position with certain activities such as walking, leaning forward, bending the knee, squatting down, etc. There are lots of things in the knee that can contribute to this popping sensation, so we must think about all the components of the knee. First, we have the bones: the femur (upper thigh bone), the tibia (lower leg bone), the fibula (smaller lower leg bone on the outside) and the patella. So, the relation of the bones to each other could be a potential source.

Next, you have cartilage between the femur and the tibia on both the inside, which we call medial, and the outside, which we call lateral. There is also cartilage between the kneecap and the trochlear area on the femur as well as between the tibia and the fibula.

Next, we have meniscal tissue where you have a lateral meniscus on the outside and the medial meniscus on the inside.

We have ligaments that are like duct tape that hold the bones together for the ligaments deep within the joint like the ACL and PCL, superficial ligaments such as the LCL and MCL just to name some.

Next, there are are the tendons. The tendons are the structures that attach the muscles to the bones, such as the quad tendon, and the patellar tendon.

Lastly, we have the actual muscles that help move the knee, such as the quadriceps and hamstring muscles.

Common Conditions That May Cause Popping Knees:

ACL Tears

The Anterior Cruciate Ligament (ACL) is one of four major ligaments in the knee. It is an important stabilizer of the knee and prevents the shin bone (tibia) from sliding in front of the thigh bone (femur). The ACL is susceptible to injury. It is most likely to be injured during activity or by impact. A torn ACL is a common injury for athletes at all levels, but it is most common for people who are active or who experience impact injuries to the knee. ACL injuries can happen to anyone of any age, condition, or ability, and it can be injured in many ways. Examples include abruptly changing direction, slowing down while running, landing incorrectly, or getting struck by someone or some object.

Read More About ACL Tears

Baker’s Cyst

A Baker’s cyst can cause knee pain. A Baker cyst is swelling caused by fluid from the knee joint protruding to the back of the knee. They are NOT a true cyst since it has communication with the synovial sac. They typically arise from degenerative changes or injury to the articular cartilage (arthritis) or meniscus. At the Centeno-Schultz Clinic, we believe that baker’s Cysts are simply a barometer of the health of the knee joint. In a healthy knee, there are absent whereas with injury and degenerative changes they are common. They arise between the tendons of the medial head…

Read More About Baker’s Cyst

Knee Arthritis

In the human body, a joint is simply where 2 ends of bone come together. At the ends of these bones, there is a thick substance called “Hyaline Cartilage” that lines the ends. Hyaline cartilage is extremely slippery which allows the two ends of the bone to slide on top of each other. Then there is a capsule that connects the two ends filled with “synovial fluid” that acts as a further lubricant to make it more slippery! Arthritis in the knee is defined by loss of the hyaline cartilage plus other changes that happen to the bone such as additional bone being laid down (bone spurs/osteophytes). The cartilage layer is worn down to the point of exposing the underlying bone they cover…

Read More About Knee Arthritis

LCL Sprain

What is an LCL Sprain? A strain or tear to the lateral collateral ligament (LCL) is known as an LCL injury. The LCL is a band of tissue that runs along the outer side of your knee. It aids in keeping the bones together while you walk, ensuring that your knee joint remains stable. How you feel and what type of treatment you’ll require depends on how severely your LCL has been stretched or torn. If it’s only a minor sprain, self-care at home might help. However, if it’s a significant tear or sprain, you may need physical therapy, an injection-based procedure, or surgery….

Read More About LCL Sprain

LCL Tear

A strain or tear to the lateral collateral ligament (LCL) is known as an LCL injury. The LCL is a band of tissue that runs along the outer side of your knee. It aids in keeping the bones together while you walk, ensuring that your knee joint remains stable. How you feel and what type of treatment you’ll require depends on how severely your LCL has been stretched or torn. If it’s only a minor sprain, self-care at home might help. However, if it’s a significant tear, you may need physical therapy, an injection-based procedure, or surgery. Orthopedists categorize LCL tears into 3 grades…

Read More About LCL Tear

MCL Sprain

The medial collateral ligament AKA MCL is a thick, strong band of connective tissue on the inside portion of your knee. It connects the top part of the tibia (shin) to the bottom part of the femur (thigh). This is a vital ligament that works along the lateral collateral ligament (LCL), anterior cruciate ligament (ACL), and posterior cruciate ligament (PCL) to bring stability, structure, and movement to the knee. The MCL provides support and stability for the inside (medial) aspect of the knee. MCL sprains are a common injury in sports such as football, hockey, and skiing. The ligament can…

Read More About MCL Sprain

MCL tear

The medial collateral ligament AKA MCL is a thick, strong band of connective tissue on the inside portion of your knee. It connects the top part of the tibia (shin) to the bottom part of the femur (thigh). This is a vital ligament that works along the lateral collateral ligament (LCL), anterior cruciate ligament (ACL), and posterior cruciate ligament (PCL) to bring stability, structure, and movement to the knee. The MCL provides support and stability for the inside (medial) aspect of the knee. MCL tears are a common injury in sports such as football, hockey, and skiing. The ligament can…

Read More About MCL tear

Meniscus Tears

The meniscus is a c-shaped piece of cartilage in the knee that functions as an important shock absorber. It is sandwiched between the thigh and shin bone. There are two menisci per knee. One on the inside portion of the knee (medial) one on the outside aspect (lateral). The knee meniscus is susceptible to injury. The most common injury is a tear in the meniscus. Not all meniscus tears however cause pain. When symptomatic a meniscus tear can cause pain, swelling, and restriction in range of motion. Tears in the knee meniscus can arise from trauma or degeneration. There are many different types of meniscus tears based upon locations….

Read More About Meniscus Tears

Patellofemoral Pain Syndrome

Patellofemoral pain syndrome (PFS), also called runner’s knee or retropatellar pain syndrome, is a significant cause of pain in the front of the knee. The pain is usually experienced behind or around the patella (kneecap) when the knee is bent or fully loaded. This post discusses everything you need to know about patellofemoral pain syndrome. 

Read More About Patellofemoral Pain Syndrome

PCL Sprain

The Posterior Cruciate Ligament is one of the paired ligaments in the middle of the knee. It is made up of 2 separate bundles: The two bundles of the PCL, and the ALB (anterior lateral bundle), and the PMB (posterior medial bundle), function synergistically to provide stability. The PCL functions as one of the main stabilizers of the knee joint and serves primarily to resist excessive posterior translation of the tibia relative to the femur. The PCL also acts as a secondary stabilizer of the knee preventing excessive rotation specifically between 90° and 120° of knee flexion. A PCL sprain happens when force is applied beyond…

Read More About PCL Sprain

PCL Tear

The Posterior Cruciate Ligament (PCL) is a paired ligament in the middle of the knee. It is made up of two separate bundles: ALB (anterior lateral bundle) and PMB (posterior medial bundle). These bundles work synergistically to provide stability. The PCL plays an important stabilizing role in the knee joint by resisting excessive posterior translation of the tibia relative to the femur. Between 90 and 120 degrees of knee flexion, it serves as secondary support for preventing excessive rotation. PCL tears happen when force is applied beyond what the PCL tensile strength is capable of resisting. The tensile strength of the PCL is well documented…

Read More About PCL Tear

Radial Meniscus Tears

The meniscus is an important fibro-cartilage structure within the knee that absorbs shock and provides cushioning. It has a semicircular ‘C’ shape and sits between the femur (thigh bone) and the tibia (lower leg bone).  The meniscus protects the two bony structures from weight, shock, and shear forces. Each knee contains two menisci, one on the outside (lateral) and one inside (medial). 

Read More About Radial Meniscus Tears
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It could be something as simple as just some air bubbles that are in the joint fluid causing some of the sensations.

Causes:

  • Mistracking of the kneecap in relation to the femur. This is what we call patellofemoral syndrome.
  • Osteoarthritis or cartilage degeneration or fraying.
  • Ligament or tendon snapping, either due to injury here because of a spur.
  • Scar tissue, perhaps from prior surgery.
  • Abnormal synovial fluid within the joint.
  • Abnormal synovium, or the lining of the knee can be inflamed.
  • Meniscal tear could be a cause.
  • Then if you do have that catching or locking sensation that could be potentially a be tear of the meniscus that causes the meniscus to become out of place or flipped, such as a flap tear or bucket[1]handle tear.
  • Also, it can be a loose body that is a broken off a piece of tissue such as cartilage, bone or meniscus that is floating in the joint causing problems.

What To Do About It:

First, it depends on what is causing the knee popping so you would need a thorough examination to figure these things out, and the cause would determine what are the potential treatments would be.

Potential treatments:

  • RICE: resting, perhaps ice, heat, or compression, elevating the leg if there is some swelling.
  • Perhaps wearing a brace can help.
  • Doing some physical therapy to correct biomechanical problems, addressing muscle deficiencies and soft tissue problems could be helpful.
  • Some of these issues may require surgery.
  • A lot of these issues that may or may not have required surgery in the past can now be helped with newer more nonsurgical procedures via injections, which help your body heal itself such as prolotherapy, PRP or bone marrow concentrate.
    • For example, if there is some patellofemoral syndrome, physical therapy would be a great place to start and if not helping enough, perhaps PRP or bone marrow concentrate which contains your stem cells would be a good choice.
    • If there is some osteoarthritis, again physical therapy could be a good place to start with PRP and bone marrow concentrate being the next step, and surgery would be a last resort.
    • If there is some scar tissue, there are certain injection based procedures that to help to loosen up scar tissue or in rare cases may need further surgery.
    • If the ligament and tendon snapping are issues, likely physical therapy can help or PRP or bone marrow concentrate can help with injuries.
    • If there is excess fluid or inflammation of the synovium, perhaps anti-inflammatories, aspirated out the fluid could be helpful, PRP or bone marrow concnetrate might be warranted, rarely surgery might be indicated.
    • For meniscal tears, physical therapy, PRP, bone marrow concentrate can be very helpful. Only for rare meniscal tears and certain flap or bucket-handle tears, surgery may be required.
    • If there is some catching, locking mechanical symptoms from those rare meniscal tears or some loose body in the knee that is actually causing the problem, which many times they do not, then perhaps surgery could be warranted as well.

Keeping Your Knees Healthy and Away From Popping:

  1. The first step to preventing the issue is maintaining healthy knees through regular exercise to keep the core, butt, and legs strong.
  2. Having a healthy diet to reduce inflammation. There are some supplements such as glucosamine, chondroitin, turmeric and fish oil that can be used to help reduce overall inflammation, which will reduce inflammation in the knees.
  3. If your knee does have an issue, have it checked out sooner rather than later by a physical therapist or a physical medicine doctor, preferably one who has alternatives to steroid injections and surgery as an only answer and that perhaps offers regenerative techniques like PRP, bone marrow concentrate, etc., like we do at the Centeno-Schultz Clinic.

THE BOTTOM LINE

Knee popping could be a mild or serious problem depending on the cause.

If you have this problem, get it checked out sooner rather than later by a musculoskeletal specialist.

If you do need more than simple home treatment, even physical therapy, a doctor can write a specific script for therapy and if that fails, you would want to go to a doctor that has experience with regenerative medicine techniques like prolotherapy, PRP, or bone marrow concentrate, as we do at the Centeno-Schultz Clinic to provide options outside of masking symptoms with medicines, or invasive surgeries that are rarely needed. Please read more about our non-surgical treatment for knees.

Be sure to download Dr. Centeno’s Orthopedics 2.0 for more information on great ways to address knee popping along with her other musculoskeletal problems.

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