Read below about pain in one knee, including causes and common questions. Or get a personalized analysis of your pain in one 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.

A.I. Health Assistant

Take a quiz to find out why you’re having pain in one knee

Take Quiz

A.I. Health Assistant Causes for Pain in One Knee

The list below shows results from the use of our A.I. Health Assistant by Buoy users who experienced pain in one knee. This list does not constitute medical advice.

  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.

    Most people get better within weeks to months of physical therapy.

    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.Meniscal Injury

    A torn meniscus is one of the most common knee injuries. Any activity that causes forceful twisting of the knee, especially when putting the pressure of one's full weight on it, can lead to a torn meniscus.

    6 to 8 weeks

    Rarity:
    Common
    Top Symptoms:
    pain in one knee, knee stiffness, knee instability, pain in the inside of the knee, swollen knee
    Urgency:
    Primary care doctor
  3. 3.Infrapatellar Bursitis

    Bursae are small fluid-filled sacks located around the body in strategic locations to provide a cushion and help reduce friction. There is a pair of bursae below each kneecap (patella). Infrapatellar bursitis is a condition where these bursae are inflamed. It is a common cause of knee pain in people whose work involves frequent kneeling on hard surfaces.

    Condition goes away on its own in a few weeks.

    Rarity:
    Uncommon
    Top Symptoms:
    pain in one knee, spontaneous knee pain, dull, achy knee pain, knee pain that gets worse when going up stairs, knee pain that gets worse when squatting
    Urgency:
    Self-treatment
  4. 4.Jumper's Knee (Patellar Tendonitis)

    Patellar tendonitis (Jumper's knee) is the inflammation of the patellar tendon, which attaches the knee cap to the shin bone (tibia). This condition is caused by frequently from sports and jumping.

    1 month with rest

    Rarity:
    Rare
    Top Symptoms:
    pain in one knee, spontaneous knee pain, knee pain that gets worse when going up stairs, knee stiffness, knee pain that gets worse when squatting
    Urgency:
    Primary care doctor
  5. 5.Knee Arthritis

    Arthritis is inflammation of one or more of the joints. Pain, swelling, and stiffness are the primary symptoms of arthritis. Any joint in the body may be affected by the disease, but it is particularly common in the knee.

    Knee arthritis is a chronic problem once it develops.

    Rarity:
    Common
    Top Symptoms:
    pain in both knees, knee stiffness, knee instability, swollen knee, morning joint stiffness
    Symptoms that always occur with knee arthritis:
    pain in both knees
    Urgency:
    Primary care doctor

    Pain in One Knee Checker

    Take a quiz to find out why you’re having pain in one knee.

    Take Quiz
  6. 6.Iliotibial (It) Band Syndrome ('Runner's Knee')

    Iliotibial band (ITB) syndrome is the lateral knee pain that results from overuse that occurs after repetitive motion. It is the most common cause of lateral knee pain in runners and cyclists.

    Within 6 to 8 weeks with conservative nonsurgical treatment

    Rarity:
    Common
    Top Symptoms:
    knee pain, pain in one knee, dull, achy knee pain, knee pain that gets worse when going down stairs, sharp knee pain
    Symptoms that always occur with iliotibial (it) band syndrome ('runner's knee'):
    knee pain
    Urgency:
    Primary care doctor
  7. 7.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.

    Conservative treatment should resolve the problem in 3-6 months.

    Rarity:
    Rare
    Top Symptoms:
    pain in one knee, knee stiffness, knee instability, knee pain that gets worse during a run, pop in the knee
    Urgency:
    Primary care doctor
  8. 8.Knee Bursitis (Pes Anserine Bursitis)

    Pes anserine bursitis is an inflammatory condition of the knee.

    Days to weeks (up to 8 weeks)

    Rarity:
    Common
    Top Symptoms:
    pain in one knee, knee pain that gets worse when going up stairs, spontaneous knee pain, knee pain that gets worse when going down stairs, knee pain that gets worse when standing up
    Symptoms that always occur with knee bursitis (pes anserine bursitis):
    pain in one knee
    Urgency:
    Self-treatment
  9. 9.Prepatellar Bursitis

    Prepatellar bursitis occurs when the bursa, a fluid-filled sac, around the knee becomes inflamed and painful.

    Recovery depends on extent of inflammation.

    Rarity:
    Common
    Top Symptoms:
    pain in the front of the knee, swollen knee, knee redness
    Symptoms that always occur with prepatellar bursitis:
    pain in the front of the knee
    Urgency:
    Primary care doctor
  10. 10.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.

    Full recovery may take months of physical therapy.

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

Questions Your Doctor May Ask About Pain in One Knee

  • Q.How would you explain the cause of your knee pain?
  • Q.Where is your knee pain?
  • Q.Do you feel like your knee is unstable, weak, or giving out?
  • Q.Did you feel a pop in your knee?

If you've answered yes to one or more of these questions, try our pain in one knee symptom checker to find out more.

Take Quiz

Pain in One Knee Symptom Checker Statistics

  • People who have experienced pain in one knee have also experienced:

    • 8% Pain in One Hip
    • 7% Lower Back Pain
    • 2% Swollen Knee
  • People who have experienced pain in one knee had symptoms persist for:

    • 40% Over a Month
    • 20% Less Than a Day
    • 19% Less Than a Week
  • People who have experienced pain in one knee were most often matched with:

    • 50% Meniscal Injury
    • 37% Patellofemoral Pain Syndrome
    • 12% Infrapatellar Bursitis
  • Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

A.I. Health Assistant

Take a quiz to find out why you’re having pain in one knee

Take Quiz