Synovitis

The synovium is a membranous tissue that surrounds the joint. It secretes synovial fluid, which reduces friction between joint surfaces, prevents adhesion, provides nutrients to articular cartilage, and removes waste products. Synovitis is a joint disease characterized by an imbalance in fluid secretion and absorption, leading to effusion, after the synovium becomes inflamed due to irritation. It can occur in various joints throughout the body, but is most common in the knee joint. Acute synovitis is more prevalent in young athletes and individuals with a history of significant trauma, while chronic synovitis is more common in middle-aged and elderly individuals, those with excessive knee joint burden, and obese individuals. Key symptoms include joint swelling and pain, weakness, localized tenderness, difficulty with extension and flexion, and impaired mobility.