Swollen legs in dogs are generally caused by arthritis, soft tissue contusions, sprains, etc. It is best to take the dog to the pet hospital for examination to find out what is causing the leg swelling, and then carry out targeted treatment. Avoid delaying the condition. During the treatment, you need to pay attention to keeping the dog warm, and then adjust the dog's diet, feed it some relatively light and nutritious food, and strengthen calcium supplementation; let the dog move appropriately, but do not exercise strenuously.