Synovial plica syndrome of the knee joint

　　Due to violent impacts on the knee joint, repeated and extensive movement of the knee joint, as well as meniscal injury, synovitis, and other joint intralesional lesions, the synovial plica is stimulated to become inflamed and swollen, proliferate, thicken, and adhere, losing elasticity. It cannot elongate and deform with the flexion and extension of the joint, and when sliding over the femoral condyle, it compresses and rubs the articular cartilage surface, causing acute and chronic inflammation of the synovium on the superior medial aspect of the joint, and even leading to erosion of the cartilage surface of the femoral patella, with the medial wall expanding and swelling, squeezing between the bony tissue, causing symptoms.

　　After continuous injury of the plica, it becomes明显 thicker, pale due to ischemia, gradually fibrotic, and under the microscope, the synovial wall becomes thickened, and the tissue beneath the synovium is replaced by fibrous tissue, with rare mononuclear cell infiltration.

　　It can cause progressive organic damage to the joint, and in severe cases, the synovium may become adherent, leading to the loss of joint function. Severe cases not only limit the movement of the knee joint but may also result in varying degrees of atrophy of the quadriceps femoris muscle, often accompanied by varying degrees of arthritis.

　　Pain in the knee may manifest as whole knee pain, pain in the front superior aspect of the knee, or pain in the anterior medial aspect of the knee, but mainly pain in the superior medial compartment of the patellofemoral joint, which is mostly dull pain. Some people may have simple knee joint cavity ache, and the pain in the knee joint becomes obvious after sitting for a long time and standing up, with limited extension and flexion. Some patients may experience locking phenomenon (a feeling of being stuck) when extending and flexing the knee joint. Most patients have transient tremors of the patella when moving the knee joint, accompanied by weak popping sounds, which improve slightly after a little movement. Jumping, climbing stairs, and suddenly standing up from a squatting position can worsen the pain, even to the point where they cannot stand up after squatting. With prolonged illness, the muscles and ligaments around the knee may atrophy due to disuse, resulting in weakness and softness of the knee joint. Some patients may have a sensation of friction when moving the knee joint, and a few patients may have effusion in the joint cavity.

　　1. The most important thing is to prevent joint injury, and attention should be paid to sufficient warm-up exercises before exercise.

　　2. Additionally, due to the gradual thickening of the synovium during the long-term chronic inflammatory process, it can affect the normal metabolism of synovial fluid, leading to serous effusion, and it can also cause fibrosis and joint adhesions, affecting normal activity.

　　3. Do appropriate extension and flexion exercises of the knee joint, do more static muscle tension exercises of the lower limb muscles, strengthen the quadriceps exercises, and generally there will be no knee joint activity dysfunction.

　　Early treatment, especially for young patients, stopping exercise and following the treatment for synovitis, most can recover completely. For those with a longer course of disease, where the synovial plica has thickened and lost elasticity, a complete surgical excision is required. The knee joint is not fixed after surgery, and active extension and flexion can be performed 5 days after surgery.

　　In the diagnosis of knee synovial plica syndrome, in addition to relying on its clinical manifestations, auxiliary examinations are also needed. X-ray films show no obvious abnormalities, arthrography shows abnormal plica, and arthroscopy can confirm the diagnosis. However, arthroscopy causes more damage than needle knife treatment, so it is not done too much.

　　The diet of patients with knee synovial plica syndrome should be light and easy to digest, with an emphasis on fruits and vegetables, a reasonable diet, and attention to adequate nutrition. In addition, patients should avoid spicy, greasy, and cold foods.

　　Early treatment, especially for young patients, stopping exercise and following the treatment for synovitis, most can recover completely. For those with a longer course of disease, where the synovial plica has thickened and lost elasticity, a complete surgical excision is required. The knee joint is not fixed after surgery, and active extension and flexion can be performed 5 days after surgery.