Pain Behind the Knee

Written By: Chloe Wilson, BSc(Hons) Physiotherapy
Reviewed by: KPE Medical Review Board

Find out about the most common causes of pain behind the knee and how to treat them

Pain behind the knee is a common problem. Not only can it affect your ability to walk and carry out your usual activities, back of knee pain can also really affect your sleep.

Also known as posterior knee pain, pain behind the knee may develop gradually over time, or suddenly with an injury. 

There may be a general ache, leg movements may be restricted by swelling or there may be a sharp pain at the back of the knee. The pain may be fairly localised to the back of the knee or may extend downwards resulting in calf pain.

What Causes Pain Behind The Knee?

Common causes of pain behind the knee are:

  • Bakers Cyst: swelling at the back of the knee
  • Ligament Sprain: overstretching one of the knee ligaments
  • Cartilage Tear: damage to the joint lining
  • Calf Tear: overstretching of one of the calf muscles
  • Knee Arthritis: wear and tear of the bones and cartilage
  • Hyperextended Knee: where the knee bends back too far
  • Hamstring Injuries: overstretching or overloading of the hamstrings
  • DVT: blood clot

Here we look at the most common causes of pain behind the knee, how and why they develop, will help you work out what is causing your posterior knee pain and how best to treat it.

1. Bakers Cyst

A Bakers cyst is the most common cause of back of knee pain. Find out about the causes, symptoms, diagnosis and treatment

The most common cause of pain behind the knee is a Bakers Cyst.

A Bakers Cyst develops when excess fluid in the knee joint seeps out into the popliteal bursa causing it to swell.

The main symptoms of a Bakers Cyst are tightness and pain behind the knee that gets worse when walking, kneeling, or bending the knee.

Treatment for a popliteal cyst focuses initially on reducing the swelling and pain behind the knee, and in severe cases the fluid may need to be drained by your doctor.

You can find out loads more about the causes, symptoms and treatment options in the Bakers Cyst Knee section.

2. Ligament Sprain

A knee sprain can cause pain behind the knee

Another common cause of pain behind the knee is a ligament sprain where one of the knee ligaments gets overstretched and tears.

Knee ligament tears are usually caused by a large force through the knee or sudden twisting movements e.g. quick pivoting when running in cleats/studs.

Common symptoms of a ligament sprain include knee instability, swelling and bruising and the associated pain behind the knee can lead to knee stiffness and difficulty walking. 

You can find out loads more about the causes, symptoms, treatment and recovery in the Knee Ligament Injuries section.

3. Posterior Cartilage Tear

A meniscus tear is a common cause of back of knee pain. Image source Orthoinfo AAOS http://bit.ly/2zWK60P

Another common cause of pain behind the knee is a tear in the cartilage at the back of the knee.

Cartilage damage may develop suddenly with an injury or gradually from wear and tear.

Cartilage injuries are usually accompanied by swelling, instability and difficulty straightening the leg and in some cases the knee may lock up.

Pain behind the knee from a cartilage tear typically gets worse when walking, running, climbing stairs and squatting. 

You can find out loads more about the causes, treatment and recovery process in the Knee Cartilage Injury section.

4. Calf Tear

A Calf Tear is a common cause of pain behind the knee. Learn about the causes, symptoms, diagnosis and treatment of calf muscle injuries

Pain behind the knee that is lower down in the calf region may be due to damage and tearing of one of the calf muscles.

Calf strains typically happened during activity, such as quickly changing speed or direction when running. If the calf muscles get over stretched and tear it can lead to swelling and pain behind the knee. 

The symptoms of calf tears typically get worse when walking or running, especially on tip toes.

You can find out loads more about the common causes, symptoms and best treatment options in the Calf Tear section.

5. Knee Arthritis

Arthritis is a common cause of posterior knee pain. Image source OrthoInfo AAOS http://bit.ly/2zVbjRN

A common cause of pain behind the knee in the over 50's is arthritis. With knee arthritis, there is gradual wear and tear of the knee bones and cartilage.

Knee arthritis may affect one or both sides of the joint and can result in bone rubbing on bone. 

Common symptoms of knee arthritis include knee stiffness (particularly in the morning), clicking or grinding noises and restricted knee mobility. Symptoms often fluctuate and may get worse during cold, wet weather.

You can find out loads more about arthritis including the common causes, stages, treatment and surgical options in the dedicated Knee Arthritis section.

6. Hyperextended Knee

A hyperextended knee is where the knee is bent back too far causing damage and back of knee pain

A hyperextended knee is an injury where the knee bends back too far. This damages the structures at the back of the knee, resulting in pain behind the knee.

Knee hyperextension is a common sporting injury that causes a sharp or aching pain behind the knee, swelling and instability. Symptoms usually get worse when standing, walking or going down stairs.

You can find out all about the common causes, symptoms and treatment options in the Hyperextended Knee section.



7. Hamstring Injuries

Hamstring injuries are a common cause of pain behind the knee and thigh

Pain behind the knee or in the back of the thigh may be caused by tendonitis or a tear in one of the hamstring muscles.

Hamstring tendonitis is an overuse injury where there is irritation and inflammation of the hamstring tendons at the back of the knee. It often affects athletes and runners.

Hamstring tears develop when one of the muscles is overstretched, beyond their elastic limit, causing some or all of the muscle fibers to tear. This typically happens during sporting activities with sudden, fast movements e.g. sprinting, lunging and jumping. 

Common symptoms of hamstring injuries include sharp pain behind the knee or in the thigh at the time of injury which is usually followed by a dull aching sensation. The pain tends to get worse when bending the knee or with sudden acceleration or deceleration. 

It is important to avoid any aggravating activities with hamstring injuries to allow time to heal - if you put too much strain through the injured muscle/tendon, it is likely to re-injure.

Gentle hamstring strengthening exercises can be started after a couple of days, as long as they don't aggravate symptoms. Once you can confidently do these without any pain, then it is really important to do hamstring stretches to regain flexibility in the muscle and ensure that the fibres heal in the right position.

You can find out everything you need to know about this cause of pain behind the knee, including causes, diagnosis, treatment and prevention in the hamstring tendonitis or hamstring strain sections.

8. Deep Vein Thrombosis (DVT)

A deep vein thrombosis (DVT) is a potentially life-threatening cause of pain behind the knee and in the calf

Another possible cause of pain behind the knee is  Deep Vein Thrombosis. A DVT is a blood clot found in one of the deep leg veins. If it breaks off it can lead to a heart attack or stroke. 

The symptoms to watch out for that indicate a possible DVT include pain behind the knee or in the calf region associated with swelling, redness and warmth in the area. Symptoms are usually only felt in one leg, not both. 

People are at higher risk of developing a DVT after prolonged inactivity e.g. long-haul plane journey or after surgery. Pregnancy, obesity, genetics and certain medical conditions also increase the risk.

Self-Test: Pull your toes up towards you (your foot doing the work, not your hands) - an increase in the pain behind the knee/calf indicates possible DVT

Safety Warning: A DVT is a potentially life-threatening condition. If you are showing symptoms of a DVT seek immediate medical attention, even if the self-test is negative.

Treating Back Of Knee Pain

So what's the best back of knee pain treatment? The best treatment for pain behind the knee will partly depend on what's causing the pain.

Generally, the first step is to reduce any swelling through a combination of RICE (rest, ice, compression and elevation) and medication, then work on knee exercises to improve the strength and stability of the knee to reduce the force that goes through the knee joint.

You can find out loads more about how to treat the different causes of pain behind the knee:

But be aware, just because there is back of knee pain, it doesn’t necessarily mean the problem is there. Pain can refer to different places so a problem around the front of the knee can produce a feeling of posterior knee pain. For more help, visit the knee symptoms diagnosis guide.

Remember, the best way to accurately diagnose the cause of your pain behind the knee is to see your doctor. 

Pain Behind The Knee Summary

The most common causes of pain behind the knee are a bakers cyst, meniscus tear, ligament sprain and hamstring injuries.

Pain behind the kneecap is usually caused by Runners Knee (problem with how the kneecap glides) or Chondromalacia Patella (thinning of the kneecap cartilage.

Tightness behind the knee is usually caused by hamstring injuries or posterior knee swelling

The most common cause of swelling behind the knee is Bakers Cyst where fluid collects at the back of the knee. Other possibilities include a calf tear, popliteal aneurysm or synovial sarcoma.

A sharp pain behind the knee, particularly after an injury is often caused by a meniscus tear. Sharp pain behind the knee in runners is often from a pulled hamstring or hamstring tendonitis, whereas in cyclists is often caused by a calf tear.

Pain behind the knee when bending the knee usually occurs when there is swelling in the knee, typically a bakers cyst.

The most common cause of pain behind the knee when straightening the leg is a meniscus tear, particularly if you've been siting down or squatting. A pulled hamstring can also cause pain and limit how far you can straighten the knee.

While in most cases pain behind the knee does not indicate a serious problem, any new incidence of posterior knee pain should be reviewed by your doctor as soon as possible.

Treatment for pain behind the knee will depend on the underlying cause but may involve a combination or RICE, exercises, a knee brace, medication and physical therapy.

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Page Last Updated: 27/02/24
Next Review Due: 27/02/26


Medical & Scientific References

Posterior Knee Pain by S. English & D. Perret. Journal of Current Reviews in Musculoskeletal Medicine, Oct 2010
Pain Behind Knee? Injury vs. Disease-Related Causes from University Health News, March 2018
Bakers Cyst - NHS UK June 2018
Meniscus Tears - OrthoInfo. American Academy of Orthopedic Surgeons