The Role and Principles of External Fixation Orthopedic Splint in Fracture Treatment
Looking at the history of fracture treatment both domestically and internationally, the oldest method of fixation, regardless of whether it's Chinese or Western, involved binding several wooden boards or bamboo strips to the injured limb ends. This shows that initial understanding and methods regarding fracture fixation were consistent. However, in modern times, due to Western development and breakthroughs, the widespread application of plaster casts and open internal fixation after the 19th century led to significant differences in the choice of fixation methods and viewpoints between Chinese and Western medicine.
The views of "extensive fixation" and "complete rest" held a dominant guiding position abroad for a long time. However, this ultimately violated the physiological functions of the limb and the biomechanical properties of bones and soft tissues, resulting in an increasing number of complications such as "fracture disease." Therefore, in the last thirty years, Western scholars have also begun to question this approach, advocating for early functional activities alongside fixation. Although the essential understanding of fracture healing is still lacking, the key lies in properly handling the dialectical relationship between fixation and activity. Based on this understanding, and following the holistic view of combining movement and stillness, Chinese and Western medicine orthopedic practitioners have developed a new set of fracture treatments characterized by novel small splint fixation using modern sciences such as physiology, pathology, and biomechanics. This has improved upon the original fracture treatments in traditional Chinese medicine.
Regarding the combination of movement and stillness in fracture treatment, modern research shows that small splint fixation can: ① effectively control fracture displacement (stillness), allowing muscle groups to contract more physiologically (movement); ③ reduce internal or external rotational or angular forces to the point where they no longer hinder or break callus formation and healing (stillness); ④ promote the dissipation of hematoma, absorption of edema, and early functional recovery (movement); ⑤ ensure the mutual promotion between neurons and muscles closely related to fracture repair (movement). [5] These arguments not only scientifically clarify the original understanding of traditional Chinese medicine but also further enrich and improve modern histological views on fracture healing.
The mechanical principle of small splint fixation for fractures is to use external fixation forces of equal magnitude and opposite direction to correspond to the tendency force of fracture re-displacement. The principle is as follows: ① The restraining force of the fabric band on the splint; ② The stress of the pressure pad on the fracture ends; ③ The necessary pulling force to counteract the muscle tension caused by overlapping and displacement of the fracture; ④ Fully utilizing the intrinsic muscle contraction power of the limb to restore the internal dynamic imbalance caused by the fracture to a state of equilibrium.
Regarding the promotion of fracture healing, it is currently believed that after fixation with a small splint, when the joints above and below the fracture site flex and extend, and the muscles along the bone shaft contract and relax, the opposing compressive forces formed at the fracture ends vary in magnitude. This counter-cyclic physiological effect can generate an electrical effect, promoting callus formation. Furthermore, activity accelerates blood circulation and promotes metabolism, creating favorable nutritional conditions for the local area, which is conducive to calcium deposition and the active growth of new cells. However, effective local fixation must be ensured during activity; otherwise, fracture healing will be hindered.
Recently, some scholars have used electrical testing methods to test the mechanism of local external fixation with splints, and have preliminarily demonstrated its biomechanical effects.
