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Pain in The Back of The Knee Symptom, Causes & Questions

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Last updated August 27, 2020

Back of the knee pain questionnaire

Use our free symptom checker to find out what's causing your pain.

Understand your pain in the back of the knee symptoms, including 8 causes & common questions.

Back of the knee pain questionnaire

Use our free symptom checker to find out what's causing your pain.

Back of the knee pain symptom checker

Symptoms of pain in the back of the knee

As the body ages, new aches and pains begin to arise. It is often difficult to differentiate symptoms of normal aging from symptoms of injury — especially in the joints. Pain in the back of the knee is one such elusive symptom. The knee is such a large, complex and consistently utilized joint that it is susceptible to various degrees of injury.

Common accompanying symptoms related to age are

Symptoms related to pain in the back of the knee that are more likely to be associated with age-related changes include:

Common accompanying symptoms of more serious injury are

Symptoms associated with more serious injuries include:

  • Inability to bear weight on the knee
  • Inability to fully straighten or flex the knee
  • Fever: In addition to redness, pain, and swelling
  • Obvious deformities in the knee or leg

Being able to differentiate these symptoms associated with pain in the back of the knee is important for preventing future injury and getting appropriate care.

Causes of pain in the back of the knee

The back of the knee is composed of various muscles, bones, ligaments, nerves and arteries. See this image to get a visual representation of the knee and all of its parts. The knee also contains fluid (synovial fluid) that lubricates and protects the joint. Many different processes can result in damage or injury to these components and cause pain in the back of the knee.

Inflammatory causes

Inflammatory causes of pain in the back of the knee may include the following.

  • Arthritis: Arthritis is a general term for multiple conditions that cause painful inflammation and stiffness of the bones and joints. Arthritic processes can affect many parts of the knee and cause irritation that often leads to pain and injury.
  • Infection: The fluid in the knee can also be infected by bacteria that causes inflammation, pain, redness and swelling.
  • Fluid excess: Inflammation and injury can cause too much synovial fluid to be produced in the knee. This extra fluid can build up and form cysts, especially in the back of the knee that cause pain.

Trauma-related causes:

Causes of pain in the back of the knee related to trauma may include the following.

  • Micro: Small injuries such as tears, strains and gradual wear and tear that affect the muscles, ligaments and bones of the knee over long period of time can result in chronic knee pain both in the front and back of the knee.
  • Macro: Large traumatic injuries can cause damage to the major ligaments and fractures to the bones of the knee. These injuries will certainly result in pain symptoms in the back of the knee.

Mechanical causes

Knee pain can also be caused by problems in alignment and orientation of the knee and other parts of the body such as the hip and foot. Lack of flexibility and strength in the muscles of the area can also affect alignment. These mechanical causes may affect how you walk and change the pressure exerted on the knee resulting in pain.

This list does not constitute medical advice and may not accurately represent what you have.

Baker's cyst (popliteal cyst)

A Baker's cyst, also called as Popliteal cyst, is a fluid-filled mass that causes a bulge and a feeling of tightness behind the knee. The pain can get worse when the knee is fully flexed or extended.

Rarity: Uncommon

Top Symptoms: calf pain, swollen knee, knee pain that gets worse when squatting, knee instability, dull, achy knee pain

Symptoms that always occur with baker's cyst (popliteal cyst): lump on the back of the knee, constant knee lump

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

Back of the knee pain questionnaire

Use our free symptom checker to find out what's causing your pain.

Back of the knee pain symptom checker

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

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

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

Hamstring strain

A strain, commonly called a "pulled muscle," is when a muscle becomes overstretched and tears. A hamstring strain happens when one of the muscles on the back of the upper leg (thigh) is pulled.

Rarity: Uncommon

Top Symptoms: spontaneous back pain, pain in the back of the knee, hamstring tightness, sports injury, hamstring pain

Symptoms that always occur with hamstring strain: hamstring pain

Symptoms that never occur with hamstring strain: groin pain, hip pain, pain in the outside of the hip, difficulty moving the hip

Urgency: Self-treatment

Rheumatoid arthritis

Arthritis is a general term for multiple conditions that cause painful inflammation and stiffness throughout the body. Rheumatoid arthritis (RA) is a chronic condition that is autoimmune in nature, meaning that the body's immune system which normally protects the body by att...

Deep vein thrombosis

Deep vein thrombosis (DVT) is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or thigh.

Rarity: Uncommon

Top Symptoms: fever, thigh pain, upper leg swelling, calf pain, butt pain

Urgency: Hospital emergency room

Pain in the back of the knee treatments and relief

At-home treatment and prevention

There are many strategies you can take to prevent knee pain and lessen your knee's susceptibility to injury.

  • Exercise correctly: Maintaining a healthy weight can reduce extra pressure and stress on the knees, but it is important to use correct form and technique during exercise as well.
  • Strengthen and stretch: Because weak muscles and mechanical issues are a leading cause of knee pain and injury, it is important to both strengthen the major muscles of the knee such as the hamstrings and quadriceps and stretch them in order to relieve tightness. Balance and stability are key in ensuring that your knee and muscles work together effectively.
  • Apply ice then heat: Putting ice on your knee will help reduce pain and relax sore or tight muscles. Limit application of ice or heat to 20 minutes at a time. You can do this every couple of hours for relief.

When to see a doctor

If you are experiencing chronic pain or pain more associated with serious injury, see your doctor promptly. Not addressing your pain properly can lead to increased pain, joint damage, and disability. Depending on the cause of your knee pain, your doctor may suggest the following treatments:

  • Medications: Your doctor may prescribe medications to help relieve pain in the back of the knee and swelling and treat underlying conditions like arthritis.
  • Physical therapy: Your doctor may prescribe stretching exercises or a physical therapy/rehabilitation program to help you restore range of motion, strength and stability to your knee.
  • Injections: In some situations, your doctor may suggest injecting medications and other substances directly into the knee joint in order to reduce inflammation, lubricate the knee and promote healing.
  • Surgery: If conservative measures do not provide relief, your doctor may recommend surgical options.

When it is an emergency

If the pain in the back of your knee becomes incredibly severe, it swells in a concerning manner, you are unable to walk, or you experience a fever, you should seek care immediately.

Back of the knee pain questionnaire

Use our free symptom checker to find out what's causing your pain.

Back of the knee pain symptom checker

FAQs about pain in the back of the knee

Here are some frequently asked questions about pain in the back of the knee.

How do you know if you have a blood clot behind your knee?

A blood clot in the veins of your lower leg is called a deep vein thrombosis or DVT. You may have a blood clot behind your knee if you have one-sided leg swelling, pain, warmth, and redness below the knee. Sometimes these clots can occur on both sides at once, but this is uncommon. Some blood clots in the legs, however, do not present with any symptoms. A DVT requires immediate treatment to reduce the risk of embolizing to the lungs.

Why does my knee hurt when I straighten it?

Your knee is made up of bones, cartilage, muscles and tendons. When you extend your knee, your quadriceps muscles (those on the front of your thigh) tighten, and your hamstrings (those on the back) relax. Pain on knee straightening is usually indicative of damage or overuse of the quadriceps muscles, leading to tiny tears in its tendon. Pain may also occur due to any damage to the joint itself. You may get pain specifically in the back of the knee due to cyst formation following injury of the joint.

Can dehydration cause pain in the back of the knee?

In general, dehydration does not cause pain in the back of the knee. However, if you are dehydrated, you may experience cramping of your muscles. This is due to electrolyte imbalances leading to muscle irritation. This can lead to pain in the back of your leg if those muscles cramp. Most commonly, dehydration leads to exhaustion, thirst, muscle cramps, and dizziness.

Can growing pains occur in just one leg?

Usually growing pains occur bilaterally or in both legs. These pains usually occur deep in the thigh or calf in school-aged children. They generally occur at night with resolution by morning. If your child is experiencing pains in just one leg, consider bringing them for medical evaluation. One-sided leg pain can be indicative of infection, musculoskeletal injury or deformity, or other serious conditions such as a tumor.

Is it possible for adults to have "growing pains"?

No one knows for certain what causes “growing pains.” They are defined as self-limited and recurrent pains in the extremities of children with no other explanation or clear musculoskeletal causes. These usually occur during sleep and may awaken the child. Some physicians believe they occur due to fatigue, overuse, and mild orthopedic abnormalities, but the cause is still unknown. No matter what causes growing pains, we know that adults do not have them — most growing pains occur between age 2 and 12. It is possible to have similar pains, however, due to very mild injuries or overuse of muscles.

Questions your doctor may ask about pain in the back of the knee

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

  • Is the knee pain affecting one or both knees?
  • Do you often feel your knees buckling?
  • Where is your knee pain?
  • How would you explain the cause of your knee pain?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

Pain in the back of the knee statistics

People who have experienced pain in the back of the knee have also experienced:

  • 7% Knee Pain
  • 6% Lower Back Pain
  • 4% Knee Stiffness

People who have experienced pain in the back of the knee were most often matched with:

  • 40% Meniscal Injury
  • 30% Baker'S Cyst (Popliteal Cyst)
  • 30% Patellofemoral Pain Syndrome

People who have experienced pain in the back of the knee had symptoms persist for:

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

Source: Aggregated and anonymized results from Buoy Assistant (a.k.a. the quiz).

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Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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