Actually, the crucial aspect in the case of this patient with blue eyes is that the surgical operation needs to be gentle.
Because brittle bone disease has led to severe osteoporosis, if the surgical skills are not proficient, and the movements are not gentle during the drilling on the femur or tibia, rough operations can easily lead to fractures.
Proficiency is the basis for gentleness. Without sufficient surgical proficiency, we cannot talk about gentle movements.
Given Director Tang's situation, a simple partial resection and reshaping of a knee meniscus would take him five hours. He hasn't mastered the procedure for the anterior cruciate ligament reconstruction surgery at all. So, how could he possibly achieve a gentle operation?
However, Director Tang has been lost in his persona as an expert for so long, forgetting his own limits and overestimating his abilities, which led to the botched surgery.
