M65.8: Other synovitis and tenosynovitis

Synovitis and tenosynovitis are medical conditions affecting the tissues around the joints and tendons. Specifically, synovitis refers to the inflammation of the synovial membrane, a soft tissue that lines the non-cartilaginous surfaces within the joints, providing lubrication to reduce friction. On the other hand, tenosynovitis involves inflammation of the synovial sheath, which houses a tendon that links muscle to bone. Both conditions can present similar symptoms, which commonly include pain, swelling, and sometimes a feeling of warmth at the affected area. Movement can often intensify the discomfort and impede flexibility and function. The inflammation may be caused by various factors, such as injuries, overuse or strain, infection, or an autoimmune response where the body's immune system mistakenly attacks its own tissues. Both conditions, if not managed appropriately, can lead to complications such as joint damage and loss of mobility.