There are several reasons due to which you can have leg pain such as conditions that affect joints, nerves, ligaments, bones, nerves, muscles, blood vessels, skin or tendons. One can have leg pain in the ankle, foot, behind the knee, knee, down the back, thigh or in any other part of the leg.

One can experience the pain during the night while lying or while exercising or running. The pain can be in either of the legs or in both as per the cause.

• Weakness
• Throbbing
• Numbness
• Cramps
• Tingling sensation
• Aching

Causes of leg pain behind the knee
Leg pain behind the knee or posterior knee pain can come in varied forms from slight to sharp pain which can occur while bending the legs. The causes are varied as well. The most common ones are listed below.

Popliteal Cysts or Baker’s Cyst
It is a common cause for leg pain behind the knee. In this, a fluid-filled cyst is developed at the back of the leg because of arthritis or any other cartilage damage. It creates a feeling of stiffness, swelling, and pain behind the knee and calf. Mostly these cysts heal without any treatment. But in case it’s not healing, you need to find out the reason behind it. It is also important that you prevent any further occurrence of the cysts in future. You can use ice, crutches, compression and other physical therapies to treat the cyst. Professionals might suggest using corticosteroid medication, fluid drainage or surgery (in rare cases).

A tear in the cartilage
The meniscus can also lead to pain in the back of the knee and the intensity will depend on the sort of tear. You will have pain as well as swelling with this condition. The pain intensifies in this condition, if the leg is bent or while getting up after sitting. Physical therapy is the best treatment for treating meniscus and other tear injuries. One can also go for meniscus bracing or in rare cases surgery.

CPPD
Calcium Pyrophosphate Dihydrate disease (CPPD) can be a cause of your leg pain behind the knee. The risk of developing this disease increases with age. People who are over 85 years of age experience CPPD. Some other risk factors involved with CPPD are mineral imbalances, joint trauma, certain medical conditions like underactive thyroid, etc. One having CPPD will experience sharp pain behind the knee and witness swelling along with warmth and redness. This happens because of the formation of crystal depositions on one’s joints. Few things can be done to reduce the pain and to provide full joint movement and muscle strengthening. Use of ice and rest along with physical therapy can help a lot in this condition. You can also consult with your doctor to get medication prescription or can consult for draining excess fluid from knee to reduce the inflammation as well as swelling. In rare cases, one can undergo surgery as well.

Athletic Hamstring
The cause of your pain could be past injuries that you must have suffered from. For example, one can pull a hamstring muscle via a sudden stretch of the muscle fibers of the hamstring. It can happen in case you are exercising without doing a warm-up, wearing inadequate footwear, tired or imbalanced muscles or prior injury.  The symptoms of this condition include bruising, swelling, knee flexion, muscle spasm, and limited range of motion. In the case of major pull, you might also hear a sound (pop). Its treatment depends on the extent of the damage. You need to follow the steps of RICE which mean rest, use ice, compression and elevation. Along with it, you will be prescribed some medications and crutches. Sometimes physical therapy is also recommended to improve the motion, strength, and flexibility of the muscles. Rarely surgery is required to repair the damaged muscles.

Tumor
Another cause of pain at the back of the knee can be a tumor that is growing in the soft tissue or bone of the knee. It usually causes discomfort, pain, and looks like a palpable mass and will also cause difficulty in bending the knee. The treatment depends on the grade and stage of the tumor and might need chemotherapy, radiation, amputation or resection. There are other reasons as well which can lead to leg pain behind the knee and need specific treatments. Therefore, it is important to know the root cause first and then undergo the treatment. Consult your doctor as soon as you start feeling the pain.