Pain in the back of the knee may be caused by an injury, cyst, or arthritis. More rarely, it can be an indicator of a serious health condition like a blood clot.

The knee is your body’s biggest joint and one of its most injury-prone areas. It’s made up of bones that can fracture or move out of joint, as well as cartilage, ligaments, and tendons that can strain or tear.

Some knee injuries can heal on their own with rest and care. Nonoperative treatments like physical therapy may also help solve many knee pains.

However, pain in the back of your knee could be a sign of a health condition that may require medical intervention.

Keep reading to learn more about some of the conditions that can cause pain in the back of your knee, and what to expect if you have one of them.

A cramp is a tightening of a muscle. Muscles in the calves are most likely to cramp. However, other leg muscles can also cramp up, including those in the back of the thigh near the knee.

You’re more likely to have leg cramps when you exercise or during pregnancy. Other possible causes include:

When you have a cramp, you’ll suddenly feel your muscle contract or spasm. The pain may last anywhere from a few seconds to 10 minutes. After the cramp passes, the muscle may be sore for a few hours.

Click here to learn how to stop leg cramps.

Jumper’s knee is a term used for patellar tendonitis. This condition is an injury to the patellar tendon, which connects your kneecap (patella) to your shinbone.

Jumper’s knee is caused by overloading or overusing the patellar tendon. For example, repetitive movements like jumping or changing direction may cause tiny tears in the tendon. Eventually, the tendon swells up and weakens.

Jumper’s knee causes pain in the kneecap. The pain gets worse over time. Other symptoms may include:

  • weakness
  • stiffness
  • trouble bending and straightening your knee

The hamstring consists of three muscles that run down the back of your thigh:

  • semitendinosus muscle
  • semimembranosus muscle
  • biceps femoris muscle

These muscles allow you to bend your knee.

Injuring one of these muscles is called a pulled hamstring or a hamstring strain. A hamstring strain happens when the muscle is stretched too far. In some cases, the muscle can completely tear. This may require surgery and can take months to heal.

When you injure your hamstring muscle, you’ll feel a sudden pain. Injuries to the biceps femoris, called biceps femoris tendinopathy, cause pain in the back of the knee.

Other symptoms include:

  • swelling
  • bruising
  • weakness in the back of your leg

This type of injury is common in athletes who play sports like soccer, basketball, tennis, or hockey. Hamstring stretches and exercises could help provide pain relief and injury prevention.

A Baker’s cyst is a term used to describe a popliteal cyst. This is a fluid-filled sac that forms behind the knee.

The fluid inside the cyst is synovial fluid. Normally, this fluid acts as a lubricant for your knee joint. However, if you have arthritis or a knee injury, your knee may produce too much synovial fluid. The extra fluid can build up and form a cyst.

Symptoms of a Baker’s cyst may include:

  • pain in and behind your knee
  • stiffness and trouble flexing your knee
  • experiencing a “locking” or “clicking” sensation
  • swelling behind your knee

These symptoms can get worse when you’re active. If the cyst bursts, you’ll feel a sharp pain in your knee.

Baker’s cysts sometimes go away on their own. However, speak with a healthcare professional if your cyst impacts your daily activities, gets bigger, or suddenly starts to hurt.

Treatment may include steroid injections, physical therapy, or having the cyst drained. Treating the underlying cause may also help clear up the Baker’s cyst.

The gastrocnemius muscle and the soleus muscle make up your calf, which is the back of your lower leg. These muscles help you bend your knee and point your toes.

Sports like tennis and squash that require you to quickly go from a standing position to a run may strain or tear the gastrocnemius muscle. You’ll know that you’ve strained this muscle by the sudden pain it causes in the back of your leg.

Other symptoms of a calf strain include:

  • pain and swelling in the calf
  • bruising and tenderness in the calf
  • trouble standing on tiptoe

Calf strain treatment will depend on the severity of the strain. For example, your treatment plan for a mild sprain may include rest, physiotherapy, and over-the-counter (OTC) pain relievers. This could take up to 8 weeks to treat.

On the other hand, a ruptured Achilles tendon may require surgery and can take up to 6 months to heal.

The meniscus is a wedge-shaped piece of cartilage that cushions and stabilizes your knee joint. Each of your knees has two menisci, one on either side of the knee.

Athletes sometimes tear the meniscus when they squat and twist the knee. As you get older, your meniscus weakens and degenerates. This makes it more likely to tear with any twisting motion.

When you tear a meniscus, you might hear a “popping” sound. At first, the injury might not hurt. But after you walk on it for a few days, the knee can become more painful.

Other symptoms of a meniscus tear include:

  • stiffness in the knee
  • swelling
  • weakness
  • tenderness
  • locking or giving way of the knee

Treatment for a meniscus tear may include:

The anterior cruciate ligament (ACL) is a band of tissue that runs through the front of your knee joint. It connects your thighbone to your shinbone, provides stability, and helps with the front and back movements of your knee.

Most ACL injuries happen when you slow down, stop, or change direction suddenly while running. You can also strain or tear this ligament if you land a jump wrong, or you get hit in a contact sport like football.

You might feel a “pop” when the injury happens. Afterward, your knee will hurt and swell up. You might have trouble fully moving your knee and feel pain when you walk.

Treatment for an ACL injury will depend on its severity. Your treatment plan may include physical therapy, rest, or ACL reconstruction surgery.

The posterior cruciate ligament (PCL) is the ACL’s partner. It’s another band of tissue that connects your thighbone to your shinbone and supports your knee. However, the PCL isn’t as likely to get injured as the ACL.

You can injure the PCL if you take a hard blow to the front of your knee, such as in a car accident. Sometimes injuries occur from twisting the knee or missing a step while walking.

Stretching the ligament too far causes a strain. With enough pressure, the ligament can tear into two parts.

Along with pain, a PCL injury may cause:

  • swelling of the knee
  • stiffness
  • trouble walking
  • weakness of the knee

Rest, ice, and elevation can help a PCL injury heal faster. You might need surgery if you’ve injured more than one ligament in your knee, have symptoms of instability, or you also have cartilage damage.

Chondromalacia happens when the cartilage inside a joint breaks down. Cartilage is the rubbery material that cushions bones so they don’t scrape against one another when you move.

The most common site of cartilage breakdown is underneath the kneecap (patella). When the cartilage is gone, the knee bones scrape against each other and cause pain.

Injury to the knee, or gradual wearing down from age, arthritis, or overuse can cause chondromalacia.

The main symptom is a dull ache behind your kneecap. The pain may get worse when you climb stairs or after you’ve been sitting for a while. Other symptoms may include:

  • trouble moving your knee past a certain point
  • weakness or buckling of the knee
  • a cracking or grinding feeling when you bend and straighten your knee

Treatment may include ice, OTC nonsteroidal anti-inflammatory drugs (NSAIDs), and physical therapy.

It’s important to note that once the cartilage is damaged, chondromalacia won’t go away. Only surgery can fix the damaged cartilage.

Arthritis is a degenerative disease in which the cartilage that cushions and supports the knee joint gradually wears away. There are a few types of arthritis that can affect the knees:

  • Osteoarthritis is the most common type. It’s a gradual breakdown of cartilage that occurs as you age.
  • Rheumatoid arthritis is an autoimmune disease in which the immune system mistakenly attacks the joints.
  • Lupus is another autoimmune disease that causes inflammation in the knees and other joints.
  • Psoriatic arthritis causes joint pain and scaly patches on the skin.

Treatment for arthritis will depend on the type, severity of symptoms, and your overall health. Your treatment plan may include:

Deep vein thrombosis (DVT) is a blood clot that forms in a deep vein inside the leg. DVT typically affects one leg.

Symptoms of a blood clot in your leg include:

  • pain in the calf or thigh, especially when you stand up
  • swelling of the leg
  • swelling of the veins in your leg
  • warmth in the area
  • red skin

It’s important to get DVT treated as quickly as possible. A clot can break free and travel to the lungs. When a clot gets lodged in an artery of the lungs it’s called pulmonary embolism (PE). PE can be life threatening.

DVT is treated with blood thinners. These medicines prevent the clot from getting bigger and stop new clots from forming. Your body will eventually break up the clot.

If you have a big clot that’s dangerous, a doctor will prescribe medications called thrombolytics to break it up more quickly.

Here are some ways to help relieve pain behind your knee:

You may be able to treat pain from a minor injury or arthritis at home. However, get immediate medical attention if you experience any of the following symptoms:

  • fever
  • severe pain
  • sudden swelling or warmth in the leg
  • trouble breathing
  • a leg that can’t hold your weight
  • changes in the appearance of your knee joint

This is especially important if you have a history of blood clots. A doctor can help determine the root cause of your knee pain and help you find relief.

When should you not ignore knee pain?

Speak with a healthcare professional if the pain behind your knee worsens, doesn’t improve with at-home treatments, or affects your daily activities. If you experience symptoms of DVT, it’s important to get immediate medical attention.

Is it better to rest or walk with knee pain?

Whether it’s better to rest or walk with knee pain depends on several factors, such as the underlying cause and the current stage of your treatment. For example, if you recently experienced a knee injury, rest may help relieve inflammation and allow your muscles to heal. On the other hand, low-impact exercises like walking may be part of your long-term treatment plan if you’re living with arthritis.

Pain in the back of your knee may have several causes. These range from mild strains that could be treated at home to health conditions that require medical treatment.

Speak with a healthcare professional if the pain behind your knee impacts your daily activities or doesn’t improve. They can provide a proper diagnosis and develop a treatment plan that’s right for you.