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Learn about your pop in the knee, including causes and common questions. Or get a personalized analysis of your pop in the knee from our A.I. health assistant. At Buoy, we build tools that help you know what’s wrong right now and how to get the right care.

Pop in the Knee Checker

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Your Pop in the Knee May Also be Known as:
Knee catching
Knee clicking
Knee locking
Knee popping

Top 6 Pop in the Knee Causes

  1. 1.Patellofemoral Pain Syndrome

    The kneecap (patella) is located directly in front of the thigh bone (femur), and should normally glide freely up and down. In this condition, called patellofemoral pain syndrome, the kneecap may rub against the thigh bone instead of gliding smoothly, causing damage and pain.

    You should visit your primary care physician. While you can safely take steps to treat this condition at home (avoiding strenuous use of the knee and taking over-the-counter pain medication), your doctor may coordinate care with a physical therapist to help manage your pain and function of the knee.

    Rarity:
    Common
    Top Symptoms:
    knee pain, pain in one knee, knee pain that gets worse when going up stairs, dull, achy knee pain, knee pain that gets worse when squatting
    Symptoms that always occur with patellofemoral pain syndrome:
    knee pain
    Urgency:
    Primary care doctor
  2. 2.Repeated Kneecap Dislocation (Patellar Subluxation)

    Recurrent patellar subluxation is the continued instability of the kneecap, which causes anterior knee pain and usually occurs laterally. It occurs unpredictably with varying durations.

    Your doctor will be able to make a diagnosis regarding the severity of your recurrent patellar subluxation using X-ray and/or MRI. Basic rehabilitation is the preferred conservative treatment, but in certain cases surgery may be necessary to stabilize the recurring dislocations.

    Rarity:
    Uncommon
    Top Symptoms:
    pain in one knee, dull, achy knee pain, pain in the front of the knee, pain in the inside of the knee, swollen knee
    Symptoms that always occur with repeated kneecap dislocation (patellar subluxation):
    kneecap dislocation
    Urgency:
    Primary care doctor
  3. 3.Dislocated Kneecap

    The kneecap connects the muscles in the front of the thigh to the shinbone (tibia). When the kneecap slips out of the groove, problems and pain often result.

    You should visit your primary care physician within the next 24 hours. The first step is to return the kneecap to its proper place, a process called reduction.

    Rarity:
    Uncommon
    Top Symptoms:
    pain in one knee, knee injury, knee pain from an injury, swollen knee, pain in the inside of the knee
    Symptoms that always occur with dislocated kneecap:
    kneecap sliding out to the side, knee pain from an injury
    Urgency:
    In-person visit

    Pop in the Knee Checker

    Take a quiz to find out why you’re having pop in the knee.

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  4. 4.Acl Injury

    The ACL (anterior cruciate ligament) is a super-important tendon that connects the femur (thigh bone) to the tibia (shin), keeping the tibia from flying forward every time a step is taken. Tearing happens in a lot of accidents and sports, unfortunately.

    You should seek immediate medical care at an ER. An ACL tear is very painful and requires surgery, and the sooner that happens, the better the outcome.

    Rarity:
    Rare
    Top Symptoms:
    knee pain, pain in one knee, knee instability, knee pain from an injury, swollen knee
    Symptoms that always occur with acl injury:
    knee pain
    Symptoms that never occur with acl injury:
    mild knee pain
    Urgency:
    Hospital emergency room
  5. 5.Osteochondritis Dissecans

    At joints where bones meet, bones are covered with a layer of cartilage which provides shock absorbance and lubrication. Osteochondritis dissecans is a condition where a piece of cartilage with a thin layer of bone detach from the larger bone, causing pain.

    You should visit your primary care physician. Conservative therapy is first considered, such as resting the joint, and physical therapy. Surgery is performed if the conservative treatment fails.

    Rarity:
    Rare
    Top Symptoms:
    pain in one knee, knee pain that gets worse during a run, knee stiffness, knee instability, spontaneous knee pain
    Urgency:
    Primary care doctor
  6. 6.Pigmented Villonodular Synovitis

    The synovium is a thin layer of tissue that surrounds joints, providing a small amount of fluid to lubricate the joint and aid in movement. In pigmented villonodular synovitis (PVNS), the synovium thickens and overgrows. This mass typically only affects one joint, is not cancerous, and does not spread to other parts of the body.

    You should visit your primary care physician who will likely coordinate care with a muscle and bone specialist (orthopedic surgeon). The treatment for PVNS is surgery and radiation therapy.

    Rarity:
    Rare
    Top Symptoms:
    pain in one knee, spontaneous knee pain, swollen knee, joint pain, pain in the inside of the knee
    Symptoms that never occur with pigmented villonodular synovitis:
    knee instability
    Urgency:
    Primary care doctor

Questions Your Doctor May Ask About Pop in the Knee

  • Q.Which of the following describes your physical fitness:
  • Q.While you are standing, take a look at your knees. Do they appear to bend towards each other, rather than follow a straight line along your legs? (Knock-kneed)
  • Q.Is your knee pain:
  • Q.Is the knee pain affecting one or both knees?

If you've answered yes to one or more of these questions, check our pop in the knee symptom checker.

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Pop in the Knee Symptom Checker Statistics

  • People who have experienced pop in the knee have also experienced:

    • 20% Knee That Clicks During Movement
    • 13% Knee Pain
    • 11% Knee Locking
  • People who have experienced pop in the knee were most often matched with:

    • 60% Patellofemoral Pain Syndrome
    • 8% Repeated Kneecap Dislocation (Patellar Subluxation)
    • 1% Dislocated Kneecap

Pop in the Knee Checker

Take a quiz to find out why you’re having pop in the knee.

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