Osteoarthritis, also known as degenerative arthritis, is one of the most common diseases worldwide and the leading cause of disability. If osteoarthritis can be detected early and treated in a timely manner, it can reduce a lot of pain, so be alert when the following four major signals are detected. Signal 1 Joint pain starts as a mild to moderate intermittent dull pain, which occurs mostly during activity and can be relieved after rest. For example, pain in patients with knee osteoarthritis is more prominent when carrying weight or going up and down stairs, while patients with hand osteoarthritis have pain with excessive hand activity. The pain develops slowly and can be persistent in severe cases, or even tear-like or pinprick-like pain, which cannot be relieved even after rest, and often wakes up with pain during sleep at night. Rest pain or nocturnal pain is the most obvious feature of the inflammatory phase. Signal 2: Restriction of joint movement The early stage is often mild, only in the morning or after sitting for a long time to feel the joint movement is not convenient, after a little activity can be relieved, this phenomenon is called “morning stiffness”. Morning stiffness usually lasts for a few minutes, and rarely exceeds 30 minutes. As the disease progresses, the symptoms gradually worsen and the range of motion of the affected joint decreases until it is fixed in a certain position. In the case of arthritis of the upper extremities, the patient may have difficulty dressing, buttoning, combing hair, carrying dishes, holding a pencil, and performing household tasks. Arthritis in the lower extremities can make it difficult to get up from a chair, stand and walk. Signal 3: Swollen joints If you feel that you can’t make a fist, have difficulty squatting, can’t take off a ring, can’t put on a watch, can’t put on an old glove, can’t put on an old shoe, etc., these are all signs of significant joint swelling, and you should go to the hospital for an examination. Signal 4: Rattling sound when moving Osteoarthritis in the late stage of development, due to the degeneration and peeling of joint cartilage, the bone under the cartilage will be exposed. When the joint moves, the bones under the cartilage at both ends are exposed and make a sound when they touch each other. If you have any of the risk factors mentioned above and experience unexplained joint pain, go to the hospital as soon as possible for an examination. The easiest and most straightforward test is an x-ray, which not only clarifies the nature and extent of the lesion, but also excludes other causes of joint disease.