M65: Synovitis and tenosynovitis

M65.1: Other infective (teno)synovitis

M65.1, or Other infective (teno)synovitis, refers to a specific inflammation of the sheath that surrounds a tendon (tenosynovitis) caused by an underlying infection. This condition typically occurs when bacteria or other infectious agents penetrate the protective layers of the skin, perhaps due to an injury or wound, and subsequently invade the tendon sheath. Common symptoms may include pain, tenderness, and swelling in the affected area, often accompanied by a reduction in mobility or function. Disease progression can cause thickening of the tendon sheath and eventually may lead to significant muscle weakness or even the inability to move the affected joint.