Symptoms A-Z

Knee Pain Symptoms, Causes & Common Questions

Understand your knee pain symptoms with Buoy, including 10 causes and common questions concerning your knee pain.

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10 Possible Knee Pain Causes

The list below shows results from the use of our quiz by Buoy users who experienced knee pain. This list does not constitute medical advice and may not accurately represent what you have.

Patellofemoral pain syndrome

Patellofemoral pain syndrome (PFPS) is also called runner's knee, jumper's knee, anterior knee pain, chondromalacia patella, and patellofemoral joint syndrome.

Overuse through training for sports is a common cause, especially if there is a misalignment in the knee joint or a previous knee injury. This wears away the cartilage beneath the kneecap and causes pain on exercising.

It is most common in females and in young adults who are active in sports, but can affect anyone.

Symptoms include dull pain at the front of the knee and around the kneecap (patella) while running, squatting, or climbing stairs, or after prolonged sitting with knees bent.

Diagnosis is made through physical examination and through x-rays, CT scan, and/or MRI.

Treatment most often involves rest; over-the-counter pain relievers; low-impact exercise such as swimming or bicycling; physical therapy to strengthen and stabilize the knee; and orthotics (shoe inserts) to help correct a misaligned stride.

Surgery is needed only for severe cases, and is done through arthroscopy to remove any fragments of damaged cartilage.

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

Meniscal injury

The menisci are the two pieces of cartilage serving as shock absorbers in the knee, between the lower end of the thighbone and the top of the shinbone. A torn meniscus is commonly referred to as "torn cartilage" in the knee.

Damage to a meniscus often happens along with another injury to the knee, especially when there is any forceful, twisting movement or a direct hit such as a tackle.

Older people may tear a meniscus through normal activity if the cartilage has become thin and worn due to aging.

Symptoms include pain, stiffness, and swelling. The knee will simply not work correctly and may catch, lock up, or give way.

Diagnosis is made through patient history, physical examination, simple motion tests, and imaging such as x-ray or MRI.

Depending on the exact form of the injury, the tear may be allowed to heal on its own with supportive care such as rest, ice, and nonsteroidal anti-inflammatory pain medication. In other cases, arthroscopic surgery followed by rehabilitation may be needed.

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

Infrapatellar bursitis

Infrapatellar bursitis is an inflammation of the bursa, or small cushioning sacs, beneath the patella, or kneecap. The condition may affect either the superficial bursa or the deep bursa.

Superficial infrapatellar bursitis is found in those whose work requires them to kneel on hard surfaces, and so it is known as housemaid's knee, clergyman's knee, parson's knee, or vicar's knee.

Deep infrapatellar bursitis can occur from chronic overuse, as with sports training and other hard physical work.

Either form of the condition can also be caused by hemorrhage, infection, traumatic injury, or inflammatory diseases such as arthropathy. Some cases may be idiopathic, meaning they occur in a particular individual for no clear reason.

Symptoms include swelling of the knee and pain below the kneecap.

Diagnosis is made through patient history and physical examination as well as x-ray, CT scan, or MRI.

Treatment involves rest; heat; nonsteroidal anti-inflammatory drugs to reduce pain and swelling; a knee brace; and sometimes corticosteroid injections into the knee.

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

Jumper's knee (patellar tendonitis)

Jumper's knee is also called patellar tendinitis or patellar tendinopathy. It is an inflammation of the patellar tendon, which runs from the bottom of the patella – or kneecap – to the top of the shinbone.

It is most often an overuse injury seen in athletes, especially those in sports involving jumping, but it can affect anyone. Strenuous physical activity without warming up first, or tightness and inflexibility in the muscles of the thighs, can put additional strain on the patellar tendon.

Symptoms include pain just below the kneecap. At first it may only appear during exercise, but later becomes chronic as the tendon becomes more damaged and inflamed. Eventually the pain interferes with normal movement.

It is important to get treatment, as the condition will not heal on its own and will only get worse through forced movement.

Diagnosis is made through patient history, physical examination, and imaging such as ultrasound or x-ray.

Treatment involves rest; pain relievers; physical therapy to return flexibility to the tendon; and sometimes corticosteroid injections or surgery.

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

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.

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

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Iliotibial (it) band syndrome ('runner's knee')

Iliotibial band syndrome is also called ITBS or IT syndrome. The iliotibial band is a long, thick piece of connective tissue that begins at the top of the hip bone, runs down the outside of the leg, and attaches at the side of the knee.

ITBS is an overuse syndrome. Athletes in heavy training are susceptible to it, especially runners and cyclists. Pain and inflammation result if the far end of the iliotibial band constantly rubs against the outside of the knee joint.

Symptoms include pain on the outside of the knee, especially while running or while sitting with the knee flexed.

Diagnosis is made through patient history and physical examination, with simple stretching tests to identify the exact location of the pain. An MRI is sometimes ordered.

Treatment involves rest; ice; over-the-counter nonsteroidal anti-inflammatory drugs; stretching exercises for the iliotibial band; strengthening of the upper leg muscles; and, if needed, changes in the way the person strides or trains. Corticosteroid injections can be helpful and surgery may be tried in some cases.

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

Osteochondritis dissecans

Osteochondritis dissecans, also called OCD, is a joint condition. It occurs when there is not enough blood flow within the end of a bone, under the protective cartilage. These bone layers begin to die and separate from the main bone, taking the cartilage with them.

The exact cause is not known. It may be due to overtraining a young person before the bone is entirely mature, which can interfere with blood supply.

Most susceptible are children and teenagers. The condition is found most often in only one joint, usually the ankle, knee, or elbow. However, any joint can be affected and there may be more than one.

Symptoms include swelling and pain in the joint during exercise, and sometimes "locking" of the joint. Osteochondritis dissecans may lead to osteoarthritis if not treated.

Diagnosis is made through patient history, physical examination, and imaging.

Treatment first involves rest because in children who are still growing, the bone and cartilage may heal spontaneously. If there are loose pieces of bone within a joint, surgery may be necessary.

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

Knee bursitis (pes anserine bursitis)

Pes anserinus means "goose's foot. In this case it refers to the appearance of the three pes anserinus tendons which lie together at the inside of the knee, about two inches below the level of the kneecap.

Pes anserine bursae are small cushion-like structures which lie between the tibia, or shinbone, and the pes anserinus tendons. Inflammation of these bursae is called pes anserine bursitis.

Bursitis is most often caused by overuse. Pes anserine bursitis is found in runners, especially when training without sufficient warmup. It can also occur where there is osteoarthritis of the knee; a knee that turns outward; or obesity.

Symptoms include pain, tenderness, and swelling of the bursa, especially with climbing stairs or other exercise.

Diagnosis is made through physical examination and x-ray.

Treatment involves rest; ice; nonsteroidal anti-inflammatory drugs for pain and swelling; physical therapy; and sometimes corticosteroid injections into the injured bursa. Surgery may be done if conservative measures do not help.

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

Prepatellar bursitis

Prepatellar bursitis is an inflammation of a fluid-filled sac (bursa) located in front of the knee (prepatellar) that normally acts as a cushion to help reduce friction. It can be caused by prolonged kneeling, such as for work, or due to injury or infection, and can either be ...

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.

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 Knee Pain

To diagnose this condition, your doctor would likely ask the following questions:

  • Is the knee pain affecting one or both knees?
  • Where is your knee pain?
  • Do you often feel your knees buckling?
  • 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)

The above questions are also covered by our A.I. Health Assistant.

If you've answered yes to one or more of these questions

Take a quiz to find out what might be causing your knee pain

Knee Pain Symptom Checker Statistics

People who have experienced knee pain have also experienced:

  • 8% Hip Pain
  • 8% Upper Leg Pain
  • 8% Lower Leg Pain

People who have experienced knee pain were most often matched with:

  • 50% Meniscal Injury
  • 37% Patellofemoral Pain Syndrome
  • 12% Infrapatellar Bursitis

People who have experienced knee pain had symptoms persist for:

  • 40% Over a month
  • 20% Less than a day
  • 19% Less than a week

Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

Knee Pain Symptom Checker

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Disclaimer: The article does not replace an evaluation by a physician. Information on this page is provided as an information resource only, and is not to be used or relied on for any diagnostic or treatment purposes.