Patients with sudden pain in the ankle cannot walk for the following common reasons: First, acute attack of gout, gout crystals enter the ankle joint in large quantities, which will induce acute synovitis in the ankle joint, with severe effusion, swelling and severe pain in the joint. Patients dare not bear weight or walk, and even rest does not bring complete relief to the symptoms. The serum uric acid test will reveal a significantly high value, and the patient usually has a previous history of gout. Secondly, ankle fracture and dislocation. Acute trauma such as ankle sprain can lead to fracture and dislocation of the ankle joint, and the patient will have severe pain and cannot walk with weight. Patients with this type of injury usually have a clear history of trauma and localized swelling and restriction of movement.