Chapter 56

The agonizingly slow afternoon finally reached three o’clock.

Director Han didn’t come back, Directors Ouyang and Bai went out for emergency surgeries, and Director Ding has always been elusive.

Director Tian and Dr. Jin both arrived. Such small study sessions were usually dominated by young doctors.

The high-resolution screen repeatedly played Professor Zhang’s surgical video.

Since quite a few people showed up, Yao Ling quickly arranged for two nurses to add some folding chairs to the room.

Zhang Lin sat at the most exterior desk in the front row, spread out a notebook, and everyone signed it one by one.

“Don’t forget to sign in, brothers,” he shouted. Anyone who had forgotten hurried over to make up for it.

Professor Zhang didn’t arrive just yet; he’d asked Yang Ping to inform him when the session was nearing the end, as he wanted to say a few words.

He said that if he were present, the youngsters wouldn’t dare speak, so he didn’t want to create chaos.

“Professor Zhang, you seem to be in high spirits today,” someone greeted Zhang Lin.

Everyone was taken aback. Damn, isn’t ‘Professor Zhang’ thrown around too casually?

“Hurry up, there are no seats left.”

“In the elevator.”

They urged each other in the WeChat group.

Almost everyone had arrived, Zhang Lin ‘Little Five’ maintained order, Director Tian checked the time, and told Song Zimo, “Start at exactly three o’clock.”

The highest-ranking attendee was Director Tian, so naturally, he presided over the meeting. He was also curious about the lecture and particularly keen to discuss Professor Zhang’s surgery. He was intrigued by the bold decision to commence weight-bearing walks so rapidly.

The room was packed with supplemental folding chairs scattered around, but it was still not enough, and some people had to stand.

Usually, for small lectures, some would find various reasons to slip away.

Except for those who were assisting with emergency surgeries at the hospital, everyone showed up today. All the interns were present, and people from other departments also came over. There’s no harm in flocking to a bustling event.

The lecture began promptly at three.

Song Zimo stepped onto the podium, characteristically sporting an open white lab coat.

He was a natural-born star with an outstanding appearance and confident demeanor. His electrifying ‘raytheon’ eyes had once captivated countless young girls.

But today, the vast majority of the attendees were males, and it seemed that, no matter how electrifying he was, it was a wasted effort.

“Biomechanics Analysis of Hip Fractures”

Biomechanics were familiar to the orthopedic doctors as it is a compulsory course in postgraduate studies.

Everyone saw these words. It felt familiar yet alien. When it came to biomechanics, barely any concepts sprung to mind besides these words.

“Everyone is very concerned about why Professor Zhang Zongshun’s patient began walking so soon post-surgery, and why the patient was bearing full weight. Today, Doctor Yang and I will use this lecture time to study and discuss this with everyone,” said Song Zimo at a moderate pace, with clear pronunciation.

“Fractures in the femoral intertrochanteric region are familiar to everyone as we regularly encounter this surgery. What doubts everyone is how can a patient with such a fracture, even a comminuted one, walk just 24 hours after surgery? And bear full weight? Is this reckless or scientifically backed? I’ll explain this now, please direct your attention to the animation displayed on the screen.”

Animation of the hip joint appeared on the screen. Based on a 3D reconstruction from the CT scans, it fully simulated Professor Zhang’s fracture at the time.

“See, Professor Zhang’s intertrochanteric fracture was comminuted, and it was comminution on the medial side. The stability of this kind of fracture completely depends on the support of the medial cortical bone. This medial cortical bone is the bearing wall. Now that the medial side is comminuted, everyone thinks that the patient can’t bear weight early post-operatively,” Song Zimo quickly delved into the focal point of the problem.

The animation continued to demonstrate, now with a simulation of the post-surgery fracture. The transmission of gravity was marked out with red lines and arrows.

A few students who were sitting close to a table laden with refreshments stealthily reached out to grab a few candies but retracted their hands promptly, lest they missed out on the key points of the lecture.

Song Zimo leaned on the podium with both hands, “This involves mechanical knowledge in orthopedics, that is, biomechanics. Most of us only have a fragmented understanding of biomechanics. If it were not for the profound impact of this surgery, I wouldn’t have realized the importance of biomechanics for orthopedic surgery. But Doctor Yang realized it and made active use of it in the surgery.”

Song Zimo came down from the podium and walked back and forth between the rows. Yang Ping was reminded of when he first arrived at the hospital; during the interview, this guy behaved in an extraordinarily arrogant manner, strutting around just like now.

“In order to achieve early weight-bearing walking with this type of fracture, two conditions must be met: anatomical reduction, to establish the condition for osseous support; and stress distribution, to relieve the load for osseous support. Look!” Song Zimo turned around to face the screen.

“I won’t go into anatomical reduction, the bone fragments are completely reset, and you don’t have any doubts. I’ll only talk about the second one, stress distribution. This is the focus today, the application of biomechanics!” Song Zimo spoke so eloquently that he turned the lecture into an impressive presentation.

Yang Ping murmured to himself: I’m working hard on surgery, and this guy is having a good time on the stage.

The teaching room was quiet, with everyone intently capturing the information presented.

“For this surgery to achieve stress distribution, the principles of tension band and barrel hoop were used.”

Everyone is familiar with tension bands, often used in fractures of the radial styloid process and the patella, where tensile stress is converted into compressive stress. But the barrel hoop principle was something they were hearing for the first time.

Some people began to scratch their heads and necks in confusion.

“The lateral steel cable here is the tension band, and the three steel cable hoops that fix the fracture are the barrel hoops.” Song Zimo returned to the stage, his mouse cursor moving on the screen.

“Pay attention to the animation. When a person walks upright, the normal gravity line goes from the spine to the second sacral vertebra, then to the hip joint, and from the head of the femur down along the lower limb gravity plumb line.”

The animation was incredibly detailed and intuitive, with a red line of gravity flowing like water along the described path.

“In a simple intertrochanteric fracture, osseous support can bear the body weight, so after anatomical reduction of a simple intertrochanteric fracture, fixation with a PFNA is completely safe for weight-bearing walking within 24 hours. But what about comminuted intertrochanteric fractures, where osseous support can’t bear the body weight? What do we do?”

What to do? A cold salad? I’m here to listen to a lecture, not to answer questions. Song Zimo got everyone thinking.

“Stress distribution is the best solution. Look at this animation.”

It was previously an animation of normal human weight transfer, but now it is an animation of a postoperative fracture model by Professor Zhang.

“The gravity starts from the femoral head and is divided into four routes: a part is transmitted downwards through the osseous support, a part is transmitted downwards through the intra-medullary nail, a part is converted into tension by the lateral tension band steel cable, and another part becomes the expansive force of the three steel cable hoops. This way, the load reducing for the osseous support prevents fracture displacement, and the load reducing for the intra-medullary nail prevents fatigue fracture.”

The animation was simple and easy to understand. There was the red line of weight distribution, one along the femoral shaft and one along the intra-medullary nail, both finally converging; two red arrows along the external steel cable showed an upward and downward pulling force; the three steel cable hoops were surrounded by arrows, as if they were about to expand and explode in all directions.

Everyone understood, while some people still did not understand, there began whispering amongst the crowd.

Dr. Jin and Director Tian sat together: “This is really clever,” said Dr. Jin. “I have used steel cables frequently in my work but never with this level of understanding. You need to be really familiar with the parameters of the bone fragment, the steel cable, and the intra-medullary nail to dare to combine them like this. And the positioning and sizing of the three steel cable hoops must be very important, especially when locking them in place, isn’t the tightness of each hoop different?”

Director Tian leaned in and said, “You’re right, the tightness and thickness of these three hoops are all different. This ensures that when weight is put on the bone, the sharp end of the main bone fragment on the inside always leans slightly toward the medullary cavity, reaching the gap. Otherwise, if it tilts outside of the medullary cavity, it wouldn’t take long for it to slide out, and the barrel hoops would become ineffective. The mechanical knowledge involved in this surgery has exceeded the common knowledge of an orthopedist, Old Jin. I’ve learnt something new today, steel cables can indeed be used in this way.”

“This guy is tricky,” said Dr. Jin. “Director Han has a keen eye for talent; I heard he was picked up from a batch of new hires.”

Director Tian laughed and said, “Do you remember? On his first day at work, he called me out on my mistake. Thanks to him, I was able to avoid falling into a big pit.”

Dr. Jin remembered, “You’re talking about that case of the concealed femoral neck fracture, right? That day I went out for a meeting and heard about it from my subordinates when I came back.”

Privately, Director Tian and Dr. Jin got along well. Despite being much older than Director Tian, Dr. Jin was highly respectful of him and did not treat him like a subordinate.

The crowd was buzzing with discussion. Everyone’s ideas were shaken up quite a bit.

Everyone here is a professional, with specialized education. These explanations, combined with animated demonstrations, helped clear almost all doubts.

Given these many mechanical principles in orthopedic surgery, was Newton actually a medical student? They wondered if he came upon his theory of gravity not because of an apple, but because of bone fracture.

Song Zimo rapped on the podium, and slowly the room quieted down: “I want to emphasize one point, if you use the same method for the next similar surgery, you will fail!”

This statement confused everyone again, they had just gained some understanding.

Song Zimo explained, “Why? Because if you don’t master the principles of biomechanics, you won’t achieve satisfactory results. The number, thickness, positioning, tension, and cross-linking structure of the steel cables are not chosen arbitrarily. Otherwise, you’d just produce a regular fixation loop, incapable of changing the direction of the force, or maintaining stability of the fracture.”

Who knew applying a loop could be so complicated?

That tension band, everyone knew about that — it’s often used in fractures of the radial styloid process and patella, but nobody thought it could be used in this ingenious way.

And the steel cable hoop too. Isn’t it usually just tied around to fix a fracture? What’s this about converting stress?

It really made their heads hurt!

Song Zimo quieted everyone down again: “Now, let’s take a ten-minute break to have something to eat. We will then continue with the discussion.”