When the old doctor received Cheng Tang's invitation, he happened to be performing an emergency surgery for a patient. As the patient's condition was critical, this surgery took twelve hours. He did not even rest after the surgery and rushed to the Kang family without stopping.
As the surgery was done overseas and it took a lot of time to reach Beijing, Lin Yuan's broken limbs were left there for too long.
The old doctor did have the ability to reattach the broken limbs, but he was really not confident that he could reattach it to Lin Yuan after more than twelve hours. The broken limbs were sealed in a special medicine and it could preserve the activity of the nerves and muscles when they were in the medicine. However, once they were taken out, regardless of whether the broken limbs could be reattached, the part that was soaked in the medicine would immediately be contaminated by the various gasses in the air when it came into contact with oxygen. By then, it would be too late.
