The knee joint is surrounded by a fluid filled capsule called the synovial membrane. A plica is a fold in this membrane. Plica syndrome occurs when one of the plica becomes inflamed. This often occurs in the middle or medial plica.
Plica is a term used to describe a fold in the lining of the knee joint. The lining of the knee joint is made up of synovial tissue. This tissue allows for the bones of the knee joint to move freely with minimal friction. These plicae form during fetal development and often are absorbed before birth. It is common for people to have remnants of these plicae in the knee joint. The medial plica he medial plica attaches to the lower end of the patella (kneecap) and runs sideways to attach to the lower end of the thigh bone (femur).
Although most with medial plica never experience any issues. It can become inflamed, typically causing pain along the inside or medial side of the knee near the patella. This usually caused through overuse or stress on the knee. Activities such as frequent running, biking, stair climbing, or direct injury to the knee can cause this plica to become inflamed.
Pain related to plica syndrome is often on the medial side of the knee. It can occur with activities such as squatting, running, even walking. You may also notice pain with sitting for long periods of time. Additional symptoms including popping, a sensation of weakness, or instability especially slopes and inclines.
Diagnosis and Treatment
Diagnosis is made through a thorough history and physical exam. Xrays may be taken to rule out any abnormalities or conditions related to the bones of the knee such as arthritis. Occasionally, MRI may be used to further evaluate the soft tissue structures of the knee.
Most cases of plica syndrome resolve with rest and activity modification. Physical therapy to strengthen the muscles around the knee joint and anti inflammatory medications to reduce pain and inflammation are also helpful and effective treatment strategies.
Occasionally, if symptoms continue a knee arthroscopy may be necessary to remove the inflamed tissue.