There may be the following reasons for having pain in the knee and ankle at the same time: 1. The most common reason for having this symptom is having osteoarthritis. Osteoarthritis is usually caused by ageing leading to osteophytes, but can also be triggered by genetic factors, joint damage, excessive joint use or excess weight. In particular, the simultaneous development of osteoarthritis in multiple joints is more likely to be genetic, as osteoarthritis caused by other factors tends to occur more often in a single joint, or in the same joint bilaterally. The degeneration of cartilage cells, which gradually calcifies and loses function, gradually leads to joint inflammation, and the degeneration of cartilage also causes the joint space to narrow, which eventually leads to abnormal joint function. 2. Pain in the knee and ankle at the same time may also be caused by gout. Gout is mostly caused by abnormal purine metabolism in the body due to dietary reasons, which causes joint inflammation in the joints, although gout is a medical disease, but it is also very common among patients seen in orthopedic surgery.