Because knees absorb the impact of stress on the body during many physical activities, they're often the site of pain and injury. While knee pain and injury most often occurs at the front of the knee, the back of the knee can also be a source of discomfort. A number of problems can cause pain and disability that originates at the back of the knee.
Baker's Cyst
Baker's cysts, also called popliteal cysts, are fluid-filled cysts that affect the back of the knee, usually as a result of knee problems such as arthritis or a tear in the cartilage. Fluid accumulates in the politeal space, making it hard to bend the knee and causing a feeling of fullness in the joint. Arthritis and meniscal tears can lead to Baker's cysts, according to March 2004 issue of "The Physician and Sportsmedicine." If the cyst ruptures, symptoms that resemble a blood clot in the leg may occur, including sharp pain and swelling that extend down the lower leg and redness in the calf, warns MayoClinic.com. Treatments for Baker's cysts include drainage of the cyst through needle aspiration; corticosteroid injections to reduce inflammation and swelling; or compression wrapping, icing and use of crutches to reduce swelling and allow healing.
Hamstring Injuries
Hamstrings muscles and tendons travel down the back of the thigh to the lower leg. Most hamstring injuries occur where the muscle and tendons join together and normally occur when a sudden strain is placed on the muscle. Pain at the back of the thigh and knee with swelling, bruising and weakness in the leg indicate hamstring injury. Immobilization, ice, rest, compression and elevation help the hamstring to heal, but complete tears usually require surgery. Recovery may take as long as three to six months after surgery, depending on the location of the repair, according to the American Academy of Orthopaedic Surgeons.
Meniscus Tear
Tears in the posterior horn of the medial meniscus cause pain in the back of the knee with knee bending or squatting. Popping or clicking sounds or sensations may also occur. Surgical repair for meniscal tears is the treatment of choice, notes The Athletic Advisor website. Bioabsorbable tacks used to repair the tear can cause pain in the back of the knee for up to six months after surgery, The Athletic Advisor states.
Tumors
Bone and soft-tissue tumors, whether benign or malignant, can cause pain at the back of the knee, according to "The Physician and Sportsmedicine." Tumors can cause the knee to lock and may cause pain that occurs even without weight bearing. The knee may not bend easily and a palpable mass may be felt.
