The main causes of joint stiffness are as follows: 1, arthritis: arthritis patients mostly have morning stiffness, which is related to inflammatory exudate in the synovial membrane and peri-articular tissues; sleep or prolonged inactivity can easily lead to the accumulation of inflammatory exudate, resulting in exudate or congestion and edema in the tissues around the affected joint, causing tension in the muscle tissue around the joint, making the joint swollen and painful or stiff; muscle contraction movement after activity, tissue fluid is absorbed by the lymphatic vessels and small veins The morning stiffness is then relieved; 2. Joint adhesions: such as local edema, repeated injury, passive pulling, infection, or foreign body irritation, long-term plaster fixation, incorrect steel pin internal fixation, and plate internal fixation, injury, not timely treatment, surgical trauma, swelling does not subside, fracture healing without timely exercise, etc. Such conditions can lead to the occurrence of joint stiffness.