Sudden inability to bend the fingers is mostly due to stenosing tenosynovitis of the fingers. Stenosing tenosynovitis of the fingers is common in the thumb of the hand, but can also be seen in other fingers, which can cause pain in the fingers, often located in the metacarpophalangeal joints of the fingers, with significant pain and pressure pain on the palmar side. If the diagnosis of stenosing tenosynovitis is confirmed, early physical therapy such as heat and microwave physiotherapy, and oral pain medication may be required. If the condition is severe, closure therapy and surgical release therapy are also required.