Pain Behind Knee: Injury vs. Disease-Related Causes

We examine the potential causes of pain behind knee. They can range from injury issues to diseases to a combination.

back of knee pain

The most common tendon behind knee pain is the biceps femoris tendon, which can become injured in activities such as kick-boxing, downhill running, or sprinting.

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Pain behind knee can be caused by a variety of conditions, the vast majority of which are injury-related. Some systemic diseases, however, can cause pain-behind-knee symptoms, and some life-threatening diseases also can be a source.

Here, we take a closer look at injuries as well as diseases that might lead to back-of-knee pain.

Injury-Related Causes of Pain Behind Knee

1. Hamstring injury

Inflammation or tearing of one of the tendons of the hamstring muscles can cause pain behind the knee cap. The most common tendon behind knee pain is the biceps femoris tendon, which can become injured in activities such as kick-boxing, downhill running, or sprinting. The pain is usually sudden in onset and localized to the back of the knee, where the tendon attaches to the bone. After the initial injury, the pain may become a dull ache that quickly intensifies with sudden movements. Some mild swelling behind the knee also may be present. Treatment involves the combination referred to as “RICE”:

  • Resting the knee
  • Icing the back of the knee
  • Compression knee bandages or braces
  • Elevation of the knee, particularly after the initial injury

Nonsteroidal anti-inflammatory drugs (NSAIDs) may be helpful for pain control. Some people may benefit from physical therapy exercises to strengthen leg muscles. (See also Knee Pain Remedies: Start with Classic “RICE” Advice and Knee Joint Pain Solutions, from Strengthening Exercises to Surgery to Alternative Treatments.)

2. Meniscus tear

Both a sudden twisting of the knee and long-term overuse can cause tears in either of the menisci, two crescent-shaped pieces of cartilage in the knee. These tears can cause pain, a “locking” sensation in the knee, swelling, and difficulty with knee extension. Treatment is similar to that of a hamstring injury (RICE and NSAIDs), although some individuals may require surgical repair of the meniscus.

3. Posterior Cruciate Ligament (PCL) injury

The PCL is one of the strongest ligaments in the knee and helps provide stability to the back of the knee. Injury causing a sprain or tear of the PCL is not as common as injuries of other knee ligaments but can occur when the knee is overextended or if there is a forceful blow to the front of a bent knee (such as might occur in a car accident). Pain and swelling behind the knee may result as well as joint instability. Because the PCL often heals well on its own, treatment is usually nonsurgical and includes a RICE regimen, NSAIDs for pain relief, and immobilization of the knee with bandages or braces. Surgery is usually only indicated if there is a concomitant injury such as a knee dislocation.

Disease-Related Causes of Pain Behind Knee

1. Osteoarthritis

Osteoarthritis (OA) is a disease characterized by degeneration of the cartilage that provides cushioning between the bones of our joints. It commonly affects the weight-bearing joints of the body like the knee, causing pain (often worse at night), stiffness, and swelling. OA can cause knee joint pain, including pain behind knee cap. Treatment includes NSAIDs and cyclooxygenase 2 inhibitor drugs (COX 2 inhibitors) to reduce inflammation and provide pain control, physical therapy to strengthen the supporting muscles of the leg, and sometimes steroid injections into the knee joint. For severe OA, total knee replacement may be indicated.

2. Rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease in which the body’s immune system attacks the synovial lining of joints causing inflammation and often distortion and destruction of the affected joints. As with OA, RA can cause pain in any aspect of the knee including the back of the knee, but, unlike OA which may only affect one knee, RA most often involves both knees. Symptoms include pain (usually worse in the morning), swelling, and stiffness. Treatment can include NSAIDs, COX 2 inhibitors, steroids, or disease-modifying antirheumatic drugs (DMARDs).

3. Gout

Gout is a disease characterized by the build-up of the waste product uric acid in the blood of affected individuals. The uric acid can form crystals that deposit in joints causing a painful “attack” or flare. When the crystals deposit in the knee, the knee can become swollen, red, and warm. Pain can occur behind the knee but also in any other part of the knee. Treatment involves pain control with NSAIDs or the drug colchicine and the use of uric acid-lowering medications as well as the adoption of a gout diet low in purine-rich foods which can contribute to uric acid levels.

Injury or Disease-Related Back of Knee Pain Causes

1. Popliteal Cyst

A popliteal cyst, also called a Baker’s cyst, is a localized swelling behind the knee that occurs secondary to an injury or an inflammatory disease. As fluid builds up in the knee joint, it can bulge out into a ball-shaped protrusion behind the knee. While it can be painless in some people, it may cause back of the knee pain in others and often causes a decrease in range of motion, particularly with knee flexion. Specific treatment of the cyst is usually not needed. Treating the underlying injury or disease is more often indicated. Rarely, the cyst is drained or surgically removed if it is particularly large.

Life-Threatening Causes of Pain Behind the Knee

1. Deep vein thrombosis

A deep vein thrombosis (DVT) is a blood clot that develops in a vein. They most often occur in the large veins of the thigh or calf and, therefore, can cause pain behind knee cap. A variety of factors can put someone at increased risk of a DVT including trauma, prolonged sitting, cardiovascular disease, or family history of DVT. DVTs behind the knee will often cause localized pain, swelling, tenderness, redness, and warmth. Because the clot can break free and travel to the lung, where it can cause a life-threatening blockage in a lung artery (pulmonary embolus or PE), DVTs represent a medical emergency. Treatment involves the use of blood thinners such as warfarin or surgical removal.

2. Tumor

Tumors are a rare cause of pain behind the knee but should be considered as a cause if other conditions have been ruled out. Liposarcomas (malignant tumors of fat tissue), synovial sarcomas (malignant tumors of synovial tissue), and osteosarcomas (malignant bone tumors) are tumors that can be found behind the knee. Benign (non-malignant) tumors such as osteochondroma can also occur in the knee. A bulging mass in the knee that may be accompanied by systemic symptoms of weight loss, night sweats, or fever can be signs and symptoms of malignant tumors in the knee. Treatment varies depending on the specific tumor but may include chemotherapy, radiation, or surgery.


Originally published in 2016, this post is regularly updated.

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Helen Boehm Johnson, MD

Helen Boehm Johnson, MD, is a medical writer who brings the experience of a residency-trained physician to her writing. She has written Massachusetts General Hospital’s Combating Memory Loss report (2019, 2020, … Read More

View all posts by Helen Boehm Johnson, MD

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  • Glad to receive your mail in my yahoo mail id. My problem is that now 70 years, active, doing water exercise, etc. Pain just behind knee while standing for long time The pain on right leg, left side of knee. Calf muscle of right leg sometime in the midnight after 2 am, catches like muscle catch, suffer for 1 to 2 minutes. I immediately stand and tap my right leg for 3 to 4 minutes, blood circulation makes the condition better and no more pain. So far no doctors could analyse and find out reasons for this. As a woman, always busy in my house work etc, walking shopping mall to purchase goods etc. Kindly guide me and what to do to improve this condition. No medication recommended by doctor but I am applying Tiger Balm etc. I tried physio therapy, acupuncture but no avail. await your guidance Thanks hare krishna money

  • I have had arthritic knees for a few years but it doesn’t stop me from playing golf, but just recently I’ve been getting pain behind my right knee. Sometimes in a stabbing censation and it it travels up the back of the leg up to the thigh and down to the ankle. Helps a bit if I try and sleep on my back with straight legs. Notice it only comes on after I’ve played a round of golf and when I’m in bed. Have you any advice on what it might be. Regards. Averil Howitt

  • My knee and calf are incredibly painful it is swollen at front and a big bulge of fluid behind and all day and especially at night it shoots dull pain constantly I am in tears every night even with a few pain killers it is that painful and has now creeped up to my lower dip in back I am 47 and feel I can’t walk far now as too much to deal with pain it makes me cross as its been nearly a year and Mri showed up fluid and nothing done I feel it may be tissue or some ligament torn as X I did fall off a motorbike in April n banged this knee, I cannot explain the pain it’s just taking my breath away too as hurts I hope u can help and advise please thk u

  • Hi,
    For a couple days I have been experiencing pain as well as slight bruising and swelling on the back of my knee. Also about a week ago, I fell while playing sports and felt a tight sharp pain in my hamstring as I fell. I was in pain and uncomfortable for the next few days. Even with that discomfort, I played a lot of soccer and basketball since I am very committed to s couple teams. After the hamstring pain subsided (I still feel it a little bit), I felt it in the back of my knee. Any idea of what is wrong?

  • My name is Ann Lee, i was doing very great until one morning i woke up with painful joints all over couldn’t even move an inch, my mum called our family doctor for check-up and i was took to the hospital later did i found out that i was diagnosed with Rheumatoid Arthritis, i bought lots of medicine as told but nothing worked out a friend of mine told me to contact Standard Herbs Home for herbal remedy which a friend of his also contacted when he was diagnosed of Rheumatoid Arthritis and they really helped him, so i contacted Standard Herbs Home and i purchased the herbal remedy and after 4 months i went for check-up and i was cured from Rheumatoid Arthritis, God bless you Standard Herbs Home.

  • I cant walk or stand without severe right leg pain.I went to my doctor who has since dropped me as a patient with severe pain and he ask if i was short of breath when this pain hits he did a d-dimmer test which was high then sent me to a vascular office who did a ultra sound.After the ultra sound he told me to wait while he called my doctor to see what to do ,no blood clot was found but I was told to go to a ortho doctor because of a bakers cyst,I didnt go but in the report thy said suspected bakes cyst insignificant findings.I feel it is more serious than they are telling me because I have swollen lymph node in my neck the size of a goose egg.I feel its to late for any kind of medical treatment at this point.When I sit this growth behind my knee presses on my siatic nerve and I can hardly get up at all. when i dry to dry my hair I have to sit down four times or more before I can get it dry, even standing a sort amount of time causes great pain,bone pain and lots of tibia pain

  • I have severe pain behind my knee, my shin, and my calf. It started out mild then rapidly became severe. I can hardly walk at all now and I want to know what is wrong with me.

  • The last couple of days when l get out of bed l am sore in the back of legs higher up and at the back of hamstring l walk a little then it comes a bit better but l find when l walk now after a little while l have to sit it’s like the legs don’t want to go

  • Sudden pain in right leg behind knee. Pain and swelling down the front of leg down to ankle. X-Ray shows nothing. Have stage 3 kidney disease, can not take ibuprofen.

  • 6 Years ago I had pain behind my right knee; I was 46 years old. I thought it was an injury and over a 2 week period I put up with the pain. It got worse. I finally went to the doctor who ordered an ultrasound. It was a DVT! I am lucky to be alive! I walked miles on it, rubbed it, tried stretching it out, but pain got worse. DO NOT IGNORE PAIN BEHIND THE KNEE!

  • I was diagnosed of Lyme disease four years ago. I was so terribly sick. I think my worst complaint was the severe headache. I was taken doxycycline hyclate 100 mg as treatment for Lyme disease, twice a day for 21 days. and didn’t seem to be improving. I did not display a rash or any kind of bull’s eye. Diagnosis was from blood test. We tried every shots available but nothing worked. My Lyme Disease got significantly worse and unbearable because of her cognitive thinking. In 2015, our physician advised we go with natural treatment and was introduced to Organic Herbal Clinic natural organic Lyme Disease Herbal formula, I had a total decline of symptoms with this treatment, the fever, joint pain, weakness, shortness of breath, and anxiety. and others has subsided.

  • Three episodes of extreme pain behind left knee. Slight swelling. 75 year old female. Couple of TIA’s. Should I see doctor?

  • I have had R A since i was 23 years old i am now 60 and my knees are so bad that i am unable to walk without pain , i have discovered an egg size hard ball in the back of my right knee , i have had bakers syst and this is different.

  • My dad used to have pain in the back of his knee, he couldn’t straighten his leg out without pain. When he gets in his car he had to lift his leg up with his hand. It also hurts to go up and down stairs. I have done extensive online research until I found this natural remedy ( ) It has really helped my dad. He has been able to relieve his knee pain naturally and without the need of any treatment.

  • I recently had hip replacement done been doing thearpy I was walking with a limp on surgery side now walking with Kane but it hurts if I bend my knee hurts in back of it it on same side of surgery

  • Came down with pain behind left knee and slightly milder pain behind right. Suspect it is sciatica due to long-standing lower back problem, golf & recent hard yard pwork. Loosens up after getting out of chair. Aleve giving some relief. Plan to visit dr and am guessing I will need xray on back and knee to establish the perpetrator.

  • I am 57 years old. Have mild osteoarthritis with no stiffness or severe pain. MRI detected tear in posterior horn of medial meniscus. No locking. No limitations in extension. I get pain in the back of my right knee varying from burning to dull ache after walking through the day controlled with acetaminophen 500mg to 1gm and rest. I wake up with no pain in the morning

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