Why is there diabetic foot instead of diabetic hand?

In the wonderful world of medicine, there are always some phenomena that make people think deeply. For example, we often hear about "diabetic foot" but rarely hear about "diabetic hand". Behind this, there are actually profound mysteries of biomechanics, anatomy and our daily living habits.

1. The hand's "clever escape" and the foot's "unfortunate hit"

If our hands and feet could talk, they might have a conversation like this:

Hand (smug): "Hey, brother Foot, I heard you're being targeted by diabetes again? Everything is fine here."

Foot (with grievance): "Hey, brother hand, you are talking without any pain. Although we are all limbs, why are our destinies so different?"

This conversation, although purely fictional, cleverly leads to our topic: Why does diabetes prefer feet rather than hands?

2. The “unequal treaty” of anatomy

First, we need to look for the answer from anatomy. Although both hands and feet are end organs of the human body, they have significant differences in structure and function.

Hands, as one of the most flexible organs in our daily life, have many delicate bones, muscles, nerves and blood vessels. These complex structures enable hands to perform various delicate operations, such as writing, drawing, typing, sewing, squeezing acne, picking toes, etc. And it is this delicacy and flexibility that allows hands to "escape" the clutches of diabetes to some extent. Because when the nerves or blood vessels in the hands are slightly damaged, we usually notice it immediately and take measures (such as rest, massage, medical treatment, etc.) to prevent the condition from getting worse.

In contrast, the structure of the feet is relatively simple and bears a large amount of weight. They are mainly responsible for supporting our body weight and bearing huge impact forces during activities such as walking and running. This high-load working state makes the nerves, blood vessels and muscles of the feet more vulnerable to damage.

Under the magic of diabetes, the nerves in the feet become dull, just like a bad cell phone signal, where you always miss important text messages like "pain", "hot" or "cold". Imagine if you walked for a day in your new leather shoes, and then you didn't find out that your feet were rubbed until the evening because the nerves in your feet were "lost". Wouldn't you feel a bit awkward?

Now let's talk about muscles. Due to the influence of diabetes, many small muscles decide to "retire" early and enjoy a leisurely old age. Now, the muscle "support team" of the foot shrinks instantly, and the whole team is in chaos. The balance between muscles is broken, resulting in the foot not being able to respond as flexibly as before when stressed. As a result, some "pressure hot spots" (stress concentration in mechanics) are formed, which are particularly prone to ulcers.

Next, blood vessels join in the fun. Due to the disruption caused by diabetes, blood vessels become narrow and tortuous, just like a one-way street in a city with countless traffic lights. Blood, the hardworking courier, carries a lot of oxygen and nutrients, but can only crawl slowly in the blood vessels, and has to stop from time to time to wait for the "green light". As a result, the tissues in the feet can only watch helplessly and complain: "Hey, brother blood, can you hurry up? We are starving!" As a result, the tissues in the feet begin to become fragile due to the "absence" of nutrients and oxygen, and the slightest disturbance can cause big problems.

Moreover, because the feet are located at the end of the body, their blood circulation is relatively poor. Once affected by diabetes, they are more likely to suffer from ischemia and hypoxia, which in turn lead to serious consequences such as ulcers and infections (Figure 1). Diabetic foot is one of the common complications of diabetes, and severe foot lesions are an important cause of death and disability for patients.

Figure 1 Diabetic foot (the image has been processed to reduce the reader's discomfort)

3. The pressure on feet is huge

You have a pair of hardworking feet that carry you everywhere every day, and endure the torture of high heels and hard leather shoes. But the worst thing is to become a "special care object" of diabetes. Why? Because diabetes likes to play a prank on your feet by putting a lot of pressure on them.

Next, we will explore this issue from the perspective of biomechanics. Biomechanics is a discipline that studies the mechanical properties and laws of organisms in terms of movement and force. In the case of diabetic foot, biomechanics plays a vital role.

When you walk on an uneven road, your feet need to constantly adjust their posture and strength to maintain balance and stability. In this process, the feet will be subjected to various impact forces and friction from the ground. Due to factors such as neuropathy and vascular disease, diabetic patients (referred to as "diabetics") will have reduced perception and adjustment abilities of their feet. This makes them more likely to have abnormal gait and uneven force when walking.

Imagine that the nerves in your feet decide to have a "pretend not to feel" party. They turn off the "pain alarm", lower the "temperature sensor", and even turn the "tactile radar" to silent mode. So when you go out wearing your new pair of hard-as-brick shoes, your feet are like saying, "Hey, master, don't worry, it's just a game!" It's not until you take off your shoes at night and see the redness, swelling, and trauma that you suddenly realize: "Oh, so you are playing this!"

From the perspective of the gait of diabetic patients, scientists have discovered through biomechanical tests that the feet of diabetic patients often present an "outward-facing" or "inward-facing" gait when walking (Figure 2).

Figure 2 Normal and abnormal gait

This gait not only increases the force area and strength of the foot, but also causes certain areas of the foot (such as the heel, toes, etc.) to bear excessive pressure. The pressure distribution in the feet of diabetic patients is uneven, and the local pressure can be several times higher than that of normal people! The nerve reaction time is also significantly prolonged, and some even take several seconds to feel pain. Over time, these areas are prone to serious consequences such as ulcers and necrosis.

The hands are much luckier. Since the hands do not need to bear the huge impact and friction like the feet, the force they bear is relatively stable. Therefore, even if the hands are affected by diabetes, the condition is often not as serious as the feet.

4. “Preference” and “Neglect” in Daily Life

In addition to anatomical and biomechanical reasons, our daily living habits are also one of the important factors that lead to diabetic foot rather than diabetic hand.

In our daily life, hands are our main tool for communicating with the outside world. Whether it is work, study or entertainment, we need to use our hands frequently. Therefore, we usually pay more attention to the health of our hands, and once we find any discomfort or abnormality in our hands, we will take immediate measures to deal with it.

In contrast, our feet are often neglected. Apart from necessary activities such as walking and running, we rarely take the initiative to pay attention to the health of our feet. Even if there are some minor problems with our feet (such as pain, numbness, itching, etc.), we often choose to tolerate or ignore them. This imbalance between "preference" and "neglect" makes the feet more vulnerable to diseases such as diabetes.

5. The serious science behind the interesting data

In order to more intuitively demonstrate the difference between diabetic foot and diabetic hand, let's take a look at some interesting research data.

According to a large epidemiological survey, the incidence of foot ulcers in diabetic patients is much higher than that of hand ulcers. Specifically, the annual incidence of foot ulcers in diabetic patients can be as high as over 15%, while the annual incidence of hand ulcers is less than 1%. This data fully demonstrates the huge threat that diabetes poses to foot health.

In addition, scientists have discovered some interesting phenomena through biomechanical tests. They found that the plantar pressure distribution of diabetic patients' feet when walking often shows a "hot spot" phenomenon, that is, the pressure in some areas is significantly higher than in other areas (Figure 3). These "hot spot" areas are often prone to ulcers and injuries. In contrast, the pressure on the hands during daily activities is relatively uniform and of lower intensity, so similar problems are not likely to occur.

Figure 3 Plantar pressure cloud map. The red area represents the high pressure area

6. Plantar pressure measurement to "check" your feet

In order to "check the feet", biomechanics have invented a variety of plantar pressure measurement methods and devices. According to the development process and application technology of plantar pressure measurement, it can be divided into foot print method, plantar pressure scanner, pressure plate and pressure insole (Figure 4).

Figure 4 Plantar pressure test method

Pressure plates, force platforms, pressure shoes and insoles are foot pressure testing systems developed on the basis of transducers and sensors. Pressure shoes and insoles place sensors in shoes and insoles, overcoming the inconvenience of carrying and adjusting force plates and force platforms. Sensors can be placed at the part that needs to be measured. Since shoes and insoles fit the sole of the foot, they can continuously measure parameters such as sole pressure and time, and can provide real-time monitoring and feedback.

The plantar detection system has a wide range of uses. The system environment can be indoors or outdoors, and can be used for standing, walking or running. For the diagnosis and treatment of foot deformities, the correction effect can be immediately determined, and the patient's foot morphology can be evaluated before and after surgery. Clinically, it can be used to observe whether the patient's gait is abnormal, screen diabetic patients and other neuropathy patients, and monitor degenerative foot diseases. The plantar detection system is suitable for a wide range of people, from children to adults to the elderly. As long as the subject is able to walk or stand, the system can be used on the subject's sole to evaluate the condition of the foot.

In clinical biomechanics, gait analysis has become an important means of diagnosing diseases and evaluating rehabilitation, and it helps to diagnose the cause and degree of deformity (Figure 5).

Figure 5 Plantar pressure measurement and gait analysis

7. Plantar biomechanical correctors protect your feet

Plantar decompression is of great significance in the occurrence, development and healing of diabetic foot ulcers. According to the International Diabetic Foot Working Group, in the prevention of diabetic foot, patients with high-risk factors should be encouraged to use decompression insoles or shoes to prevent the occurrence of ulcers.

Biomechanical orthotics are of great significance in the prevention and treatment of diabetic foot. The structural design of biomechanical orthotics can reduce abnormal pressure, stress and plantar soft tissue damage. The most common biomechanical orthosis is the diabetic foot corrective insole (Figure 6). Corrective insoles can reduce plantar pressure, improve local blood circulation, relieve pain, and have a significant effect on preventing diabetic foot ulcers and reducing amputations (Figure 6).

Figure 6 Biomechanical correction insole

During the treatment process, reducing local pressure can also shorten the wound healing time. However, since each person's weight, walking posture, and joint structure are different, the decompression measures are also different, and the production of biomechanical correctors must be completely personalized.

Design principles of biomechanical orthotics: ① Design and customize according to plantar pressure and biomechanical plasticity of the arch; ② Ensure uniform distribution of plantar pressure; ③ Consider the coordination between shoes and biomechanical orthotics in terms of materials and shapes; ④ The inside of the shoe is deepened to accommodate the biomechanical orthosis to ensure optimal comfort; ⑤ The forefoot area is widened and deepened to ensure sufficient space for the toes to avoid vertical and horizontal squeezing.

8. Give your feet “special care” in daily life

Now that we understand the differences between diabetic foot and diabetic hand and the reasons behind them, let’s talk about how to give your feet more love!

First of all, regularly checking the health of your feet is one of the important measures to prevent diabetic foot. We should regularly observe the skin color, temperature, humidity, and whether there is damage, infection, etc. of the feet. If any abnormality is found, you should immediately seek medical attention and take appropriate treatment measures.

Secondly, choosing the right shoes and socks is also the key to protecting the health of your feet. We should choose shoes and socks that are breathable, soft, comfortable, and of the right size to give our feet a comfortable "home" and avoid wearing shoes that are too tight or too hard to avoid unnecessary friction and squeezing of the feet.

In addition, it is also very important to keep your feet clean. We should wash our feet with warm water every day and wipe them dry to avoid bacterial growth and infection. At the same time, we can also promote blood circulation and nerve recovery in the feet through massage and hot compress to relieve foot fatigue and discomfort. Giving your feet a break is like letting them enjoy a beautiful dream of "sleeping until you wake up naturally", which is comfortable and stress-relieving.

Finally, I would like to remind everyone to maintain a good living habit and mentality. We should actively control blood sugar levels, avoid bad habits such as smoking and drinking, maintain adequate sleep and proper exercise to enhance the body's immunity and resistance. At the same time, we should also maintain an optimistic attitude and actively face the challenges and difficulties brought by chronic diseases such as diabetes.

IX. Conclusion: Harmonious coexistence of hands and feet

The more common causes of diabetic foot than diabetic hand are mainly related to the combined effects of lower limb weight bearing and pressure distribution, neuropathy and sensory loss, muscle and joint dysfunction, vascular disease and blood circulation disorders, and biomechanical abnormalities. These factors interact with each other and jointly lead to the high incidence and severity of diabetic foot.

From the above introduction, we not only appreciate the unique charm of biomechanics, but also deeply understand the important influence of anatomy, daily living habits and other factors on foot health. By understanding this knowledge, we can better care for our foot health and prevent the occurrence of serious complications such as diabetic foot. At the same time, we should also realize that hands and feet are important parts of our body, and they each have different roles and tasks. Only when we give them enough care and love can they live in harmony and create a better life for us together with "deep love between brothers".