Meniscal Cyst

Between the bones of the knee joint are two shock absorbing pieces of tissue called menisci (outer meniscus and inner meniscus). Besides acting as a shock absorber, the menisci help the thigh bone (femur) and the shinbone (tibia) fit together better. They also help supply nutrition to the cartilage of the knee joint, and help stabilize the knee. As people age, the menisci become more vulnerable to tearing. A tear in one of the menisci may cause joint irritation, which results in fluid production. This excess fluid can push out the joint covering sac (capsule), through a one-way valve, forming a firm cyst.

SYMPTOMS

  • Sometimes, a painless bump.

  • Pain, especially with standing on the affected leg. Tenderness along the joint line of the knee.

  • Firm bump at the cyst, often at the outer side of the knee, that may be easier to see when the knee is straight.

  • Swelling within the knee joint.

  • Locking of the knee joint, causing inability to straighten or bend the knee completely.

  • Giving way or buckling of the knee.

CAUSES

A meniscal cyst often develops after a meniscal tear. Meniscal tears are often associated with aging, but may also occur from injury to the knee (pivoting or twisting injury). Kneeling or squatting may also cause the meniscus to tear.

RISK INCREASES WITH:

  • Contact sports (football, rugby, lacrosse). Sports that involve cleats and pivoting (soccer). Sports that require good shoe grip and sudden change in direction (squash, racquetball, basketball).

  • Previous knee injury.

  • Associated knee injury, especially ligament injuries.

  • Poor knee strength and flexibility.

PREVENTION

  • Warm up properly and stretch before activity.

  • Maintain physical fitness:

  • Thigh, knee, and leg strength.

  • Flexibility and endurance.

  • Learn and use proper technique for jumping and pivoting in sports.

  • For jumping or contact sports, protect vulnerable joints with supportive devices, such as wrapped elastic bandages, tape, or braces (these have not been proven effective).

  • Wear proper protective equipment and ensure correct fit, including proper length cleats for the surface.

PROGNOSIS

Meniscal cysts typically do not heal naturally. Many mensical cysts do not cause pain or disability and would not be treated. If symptoms occur, surgery is the definitive method of treatment. Healing occurs within 6 weeks after surgery.

RELATED COMPLICATIONS

  • Frequently recurring symptoms, resulting in a chronic problem.

  • Repeated knee injury, especially if sports are resumed too soon, after injury or surgery.

  • Tear gets larger(progression of the tear) or cyst size increases, if untreated.

  • Arthritis of the knee.

  • Complications of surgery, including infection, bleeding, injury to nerves (numbness, weakness, paralysis), continued pain, giving way, locking, nonhealing of meniscus (if repaired), need for further surgery, knee stiffness (loss of motion), and recurrence of cyst.

  • Erosion of bone and joint, due to pressure from the cyst.

  • Injury to nerves, due to pressure from the cyst.

TREATMENT

Treatment first involves ice and medicine, to reduce pain and inflammation. Sometimes, the cyst contains fluid, which is removed through a needle (aspirated). To reduce symptoms, surgery is often advised. Surgery is usually performed through an incision near the joint (arthroscopically) and the meniscal tear is removed. The cyst may also be removed. After surgery, it may be necessary to perform strengthening and stretching exercises, to regain strength and a full range of motion. Exercises may be done at home or with a therapist.

MEDICATION

  • If pain medicine is needed, nonsteroidal anti-inflammatory medicines (aspirin and ibuprofen), or other minor pain relievers (acetaminophen), are often advised.

  • Do not take pain medicine for 7 days before surgery.

  • Prescription pain relievers are usually prescribed only after surgery. Use only as directed and only as much as you need.

  • Corticosteroid injections are used in extreme cases, to reduce inflammation. These injections should be done only if necessary, because only a limited number of injections may be given.

COLD THERAPY

  • Cold treatment (icing) should be applied for 10 to 15 minutes every 2 to 3 hours for inflammation and pain, and immediately after activity that aggravates your symptoms. Use ice packs or an ice massage.

SEEK MEDICAL CARE IF:

  • Symptoms get worse or do not improve in 2 weeks, despite treatment.

  • New, unexplained symptoms develop. (Drugs used in treatment may produce side effects.)