Synovial plica syndrome of the knee

The synovial plica of the knee joint is mainly composed of loose connective tissue; as the knee joint moves, it can change shape accordingly to adapt to the spatial shape of different postures, and the plica does not produce friction as it glides over the femoral condyles. However, due to the following reasons, the plica often develops chronic inflammation and causes symptoms. A series of intra-articular lesions of the knee, such as knee instability, snapping and pain, caused by repeated injury or stimulation leading to degeneration and hyperplasia of the synovial plica, is called knee synovial plica syndrome. Because its signs are similar to meniscal injury and chondromalacia patellae, and routine examinations are difficult to confirm the diagnosis, it is often overlooked clinically; without targeted treatment early on it becomes persistent and unhealed, eventually requiring surgery. If diagnosed early, comprehensive treatment mainly with acupotomy can achieve good results. Knee pain may present as whole-knee pain, anterosuperior knee pain, or anteromedial knee pain, but it is mainly pain in the superomedial patellofemoral joint space, mostly dull pain. Some have only intra-articular aching, with obvious knee pain and restricted extension and flexion after standing up from sitting for a long time; some patients have locking (a catching sensation) when extending and flexing the knee. Most patients have transient patellar tremor when moving the knee, accompanied by a faint snapping sound that improves after a little movement. Pain worsens when jumping, climbing stairs, or suddenly standing up from a squat, and some cannot even stand up after squatting. With a long course, disuse atrophy of the muscles and ligaments around the knee may appear, the knee feels weak, some patients have a friction sensation when moving the knee, and a few have intra-articular effusion.

Common Symptoms

Knee pain; snapping and pain in the knee joint space; Yi Yupin; inability to fully extend the knee

Causes

Violent impact on the knee, repeated heavy knee movement, and intra-articular lesions such as meniscal injury and synovitis stimulate the synovial plica, causing inflammation, edema, hyperplasia, thickening and adhesion, so that it loses elasticity and cannot stretch and deform with joint flexion and extension; as it glides over the femoral condylar surface it compresses and rubs the articular cartilage, causing acute and chronic inflammation of the superomedial synovium, and even leading to erosion of the femoral-patellar cartilage surface; hypertrophy and swelling of the medial wall, squeezed between bony tissues, causes symptoms. 1. Direct blunt injury to the synovial plica. 2. High-volume activity of the knee joint. 3. Traumatic synovitis caused by intra-articular knee lesions. After repeated injury the plica markedly thickens, becomes ischemic and pale, and gradually fibrozes; microscopy shows thickened synovial walls, subsynovial tissue replaced by fibrous tissue, with scant mononuclear cell infiltration.

Treatment

Surgical treatment, supportive treatment, rehabilitation therapy

Prevention

1). The most important thing is to prevent joint injury and to do warm-up exercises before sports. 2). In addition, because the synovium gradually thickens during long-term chronic inflammation, affecting the normal metabolism of synovial fluid, serous effusion may occur, and fibrosis may cause joint adhesion, affecting normal movement. 3). Appropriately perform knee extension and flexion exercises, do more static muscle-tension exercises for the lower-limb muscles, and strengthen quadriceps training; in general, knee mobility disorders will not occur. Especially in young patients, most can recover after stopping exercise and treating as synovitis; for those with a long course and a thickened, non-elastic plica, complete surgical resection is required. After surgery the knee is not immobilized, and active extension and flexion can be performed 5 days postoperatively.

Recommended Department

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Warm reminder: The above information is provided for health education reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek care at a regular hospital in time.