For middle-aged and older people, joint pain is more common. Many people think it is a degenerative joint disease caused by aging, and even if they go to the hospital, they only take simple X-rays and treat it negatively, taking only anti-inflammatory and analgesic drugs to prevent pain. In fact, it is not known that there are many joint pain conditions that are caused by some joint lesions. These lesions can be clearly diagnosed through further tests (e.g. MRI) and then treated through minimally invasive arthroscopic surgery to eliminate joint pain, slow down joint degeneration, and repair and rebuild damaged structures to maximize the function of the joints. There are many joints in the human body, but joint pain tends to occur in the shoulder joint of the upper extremity and the knee joint of the lower extremity, which is related to the structure and function of the joint. The shoulder joint consists of the head of the humerus and the glenoid of the scapula, also known as the glenohumeral joint. The tendons and ligaments surrounding the joint play an important role in stability, and its joint structure facilitates the movement of the joint but reduces the stability of the joint. Its main role is to move, and it is the most flexible joint in the body; long-term movement of the joint, especially in some occupations that require repeated over-lifting, can easily bring about wear and tear of the joint, and once there is significant traumatic stimulation, this damage can be exacerbated and joint pain can occur. Injury is the most common cause of shoulder joint pain, so to speak. Injuries can be violent injuries caused by a definite violent action that can lead to bony damage to the shoulder joint or, more commonly, injuries to the soft tissues inside and outside the shoulder joint, such as the glenoid labrum, ligaments, tendon sleeves, cartilage, etc. These injuries invariably cause pain in the shoulder joint, while greatly limiting the function of joint movement. These middle-aged and elderly patients think that the shoulder joint pain is “frozen shoulder”; they think that if they increase the movement of the joint, they can eliminate the pain and restore the movement of the joint. In fact, this is a misconception. First of all, the diagnosis of “frozen shoulder” is not accurate. These degenerative disorders of the shoulder joint in the elderly are not “frozen shoulder”, but are mostly due to long-term repeated lifting of the shoulder joint, resulting in rotator cuff injury due to shoulder impingement, which leads to shoulder pain and limited joint movement. This pain increases with activity, especially at night, and often affects sleep or wakes you up with pain after sleeping. This is because during sleep, the joint loses the influence of gravity on the upper extremity, resulting in a narrowing of the joint space, and the shoulder capsule or other tissues around the shoulder joint are stimulated by pressure or pulling, resulting in pain. For pain arising from such degenerative disorders of the shoulder joint, careful examination can be performed to clarify the cause, and these lesions can be treated arthroscopically, while repairing the damaged structures; this can effectively eliminate joint pain and restore its function. As the largest joint in the human body, the knee joint has a complex composition and ensures the movement of the limb under weight. It is particularly vulnerable to injury and pain. Knee pain can be caused by the following conditions: (1) patellofemoral hypertension (chondromalacia patellae), the most common patellofemoral disorder, is also the main cause of knee pain in middle-aged and elderly people. The patella is associated with the femoral trochanter and is under constant pressure during up and down movements of the limb. If the patellofemoral development is disproportionate, the articular cartilage is more likely to wear away and cause pain. It occurs in people who walk, climb or squat frequently. Patients may feel pain in the knee joint, especially when squatting, but there is no restriction of joint movement. (2) Meniscal injury is a common sports injury that can occur even inadvertently. The injury occurs when the lower extremity is weight-bearing, the foot is immobilized, and the knee is slightly flexed. A meniscal tear may be caused by sudden excessive internal or external knee extension. A meniscal injury is characterized by a distinct tearing sensation in the knee, followed by joint pain, limited motion, and a walking limp. The joint exhibits swelling and slippage, and there is a popping sound when the joint is moved, occasionally causing joint locking. (3) Various types of knee synovitis. The synovial membrane of the knee is one of the main structures that make up the knee joint. Synovial cells secrete synovial fluid, which keeps the cartilage surfaces of the joint slippery and increases the range of motion of the joint. When the synovium becomes heavily proliferated due to trauma or other factors, a large amount of fluid is produced, which increases the pressure in the joint, causing pain and interfering with normal activities. Patients may feel pain, swelling, pressure and pain in the knee joint and have difficulty moving. (4) Osteoarthritis of the knee joint is a condition seen in middle-aged and elderly people, mostly women. Wear and tear of the joint load is the main cause of the disease. If cartilage defects lead to weight-bearing pain, accompanied by swelling of the knee joint; sometimes there are broken bone fragments in the joint causing joint locking and friction sounds in the moving joint. In addition various pain-causing factors of the joint fluid cause nocturnal pain in the joint. As the disease progresses, changes in joint stresses occur, leading to inversion deformity of the knee with medial pain. (5) Knee ligament injury. The ligaments that stabilize the knee are the anterior and posterior cruciate ligaments within the joint and the medial and lateral complex ligament structures, which ensure the stability of the joint in the anterior and posterior internal and external directions. Injury to any of these ligaments can result in poor knee stability. If these damaged ligaments are not repaired, the result is excessive wear and tear on the joint, despite the ability to perform daily activities. These patients have a clear history of trauma, knee pain, pressure, and significant instability on movement, as well as limited knee motion. These lesions that cause knee pain are not self-healing. If they are not treated immediately, degeneration of the joint will accelerate. Therefore, these joint pains should be diagnosed early so that the best time to treat them is not delayed. The vast majority of these conditions can be cleaned up and repaired arthroscopically, which will remove the cause of the joint pain and restore the function of the joint.