The synovial membrane is a connective tissue that covers the joint capsule, a bubble-like structure that surrounds joints such as the knee, hip, ankle, wrist or shoulder. It is composed of the stratum fibrosus, a tough outer layer, and the synovium, a soft inner layer. Within both layers is synovial fluid, a viscous liquid very rich in hyaluronic acid that lubricates the joint to reduce friction on the articular cartilage during movement.
The synovial tissue, fibrous stratum or synovial layer becomes inflamed, usually due to an arthritic disease, synovitis occurs.
The most common cause of synovitis, in a healthy person, is excessive impact on the joints. It usually occurs in athletes or people with repetitive physical work. It can also occur due to trauma, infection, crystal deposits, or autoimmune diseases such as lupus, psoriasis, or rheumatoid arthritis.
Synovitis can be chronic if it lasts at least six months or acute if it lasts a few days or several weeks.
Toxic synovitis, especially in children before puberty, causes pain in the hip and causes lameness. It is of unknown cause.
The main symptom of synovitis is arthralgia, pain in the joints, which can be in one point or generalized. There may also be visible swelling and hypersensitivity to touch.
The rheumatologist will first rule out, in a physical examination, that it may be tendonitis, an inflammation of the tendons. To confirm the diagnosis of synovitis, a magnetic resonance imaging (MRI) or musculoskeletal ultrasound will be ordered.
The standard treatment for synovitis is rest and taking anti-inflammatory drugs. In some cases steroid injections may be necessary. If there is no response, surgery may be considered to remove the synovial fluid.
Taking care of the joints, doing regular exercise, having a healthy and balanced diet and reinforcing them with chondroprotectors if indicated by the doctor.
