There are 41 joints in the foot, accounting for 84% of the number of joints in both lower limbs. It has a three-dimensional anatomical structure and complex and subtle motor functions. The various movements and balance of the human body on the earth are all related to the landing and force areas of the foot. Therefore, the anatomical axis, biomechanics and functional reconstruction of the foot and ankle involve more problems than those of the hip and knee joints.
In the past hundred years, modern science has obtained many results on the anatomy and physiology of the foot and ankle, biomechanics and the research, prevention and treatment of foot and ankle diseases, but there is still a lack of clear research conclusions on the occurrence, development process, physiological function and stress changes of the foot and ankle, the relationship between lower limb movement and blood circulation, and the relationship between walking style and human personality characteristics. The treatment of various foot and ankle diseases also lacks normative guidelines with international authority. Based on the experience of implementing nearly 10,000 foot and ankle deformity corrections, the authors propose a modern concept of foot and ankle deformity correction.
1.Explore the causes of foot and ankle deformities with the holistic view of human upright walking
From the hind claws of the primate great apes with multifunctional functions such as grasping, to the evolution of the foot and ankle deformity, we have developed a new concept of ankle deformity. The human foot with arch-like osteoarticular structure formed by the inward retraction of the female fingers, the enlargement of the heel and the arch of the foot, thus laying the foundation for the hominid body to walk upright and with only two feet to carry weight. The foot is characterized by “flexibility in stability”. The ankle-joint-based locomotion includes the three-dimensional movement of other micro-movement joints in the foot, thus forming the natural oscillating movement and “gait beauty” in human standing, walking and running.
However, there are still evolutionary weaknesses in the human foot, such as the inversion muscle group is significantly stronger than the valgus muscle group, the strength of the ankle joint ligaments is not suitable for the human body to stand for a long period of time,? deformities such as maternal ectropion, flatfoot syndrome, and horseshoe clubfoot are only seen in the human foot.
From the perspective of individual development process, infants are born with flat feet, learn to walk when the foot ligaments and tendons strengthen, so that the middle of the foot bones bulge to form the arch, this process is usually completed by the age of 16. This process is usually completed by the age of 16. It can be seen that the arch, which has a spring effect, is a product of the developmental and walking process.
Upright walking is the fundamental characteristic that distinguishes humans from all mammals, and all other characteristics, including brain intelligence, were developed on the basis of upright walking. The change from a quadrupedal walking animal to a bipedal walking animal increases the stress on the ankle-foot joint, thus becoming the main cause of numerous foot and ankle deformities and diseases in humans.
The incidence of foot deformities, degenerative joint diseases and blood circulation disorders has increased significantly compared to that of the upper limbs. Using the natural view of biological evolution, the study of the structure, physiology and movement of the human foot, the macroscopic causes of foot and ankle disorders and the impact of functional changes of the foot on the functions of the whole body will provide clinicians with a new perspective for observation and research.
2.To correct foot and ankle deformity, we should pay attention to the patient’s physique and the line of holding gravity of the lower limbs
The human body’s balance function of standing and walking is the result of the unified and coordinated movement of the trunk, all starting from the foot. Congenital physical characteristics (e.g. height, obesity, joint laxity) and the type of living and working area can affect the occurrence and development of certain foot and ankle disorders. Any change in the overall line of gravity and anatomical axis of the lower extremity and a mild imbalance in the strength of the muscles of the foot and ankle joint can affect the landing of the foot, the site of force and stress changes, which can lead to or influence the development of foot and ankle deformities.
Therefore, when correcting foot and ankle deformities, the influence of the patient’s physical type and life pattern on the foot and ankle deformity should not be ignored, and attention should be paid to the X-ray examination of the overall force lines of the lower limbs and the determination of muscle strength. A seemingly simple deformity, such as inversion or valgus deformity of the foot, often has multiple skeletal deformity changes and tension changes of the internal and external, anterior and posterior tendons and ligaments of the ankle-foot joint at the same time.
If correction of ? If the deformity is due to inversion or valgus of the lower extremity, the relationship between the gravity line of the lower extremity and the anatomical axis of the knee and ankle joint can be accurately measured to correctly understand the cause of the dynamic deformity of the foot and accurately grasp the method and scale of the deformity correction. If the foot deformity is secondary to the change of knee or calf axis, while correcting the foot and ankle deformity, the knee or tibia deformity must be corrected to restore the normal gravity line of the lower limb.
3.Foot deformity correction by joint fusion towards the direction of retaining joint function
The fusion of three joints used to be the gold standard for the correction of all bony deformities of the tarsus, but long-term follow-up revealed that the inward and outward motion of the foot was limited or lost, the elasticity of the foot decreased during walking, the stress of the ankle joint was concentrated, and most patients developed early degenerative joint degeneration secondary to the adjacent joints. Due to the emergence of minimally invasive and natural reconstruction concept, it is possible to correct the deformity of the foot with less or no fusion of the intertarsal joint through multiple osteotomies of the heel and tarsal bones without transarticularization and postoperative application of adjustable bone external fixation techniques, thus preserving the three-dimensional multi-level micro-motion of the foot.
The development of foot and ankle arthroscopy and artificial joint has gradually brought the treatment mode of certain diseases of foot and ankle joint into a new stage of minimally invasive, limited and alternative. It is obviously a common goal for patients and doctors to turn painful joints into painless joints and dead joints into living joints. If the ankle joint is seriously damaged, artificial joint replacement should be considered first, and ankle joint fusion should be chosen as a last resort.
4.The correction of foot deformity is a combination of aesthetic repair
The civilization process of society and people’s demand for beauty promote “foot and ankle surgery orthopedic technology must be combined with the concept of aesthetics, and some people even implement orthopedic surgery for the aesthetic requirements of the foot.” This requires modern orthopedic surgeons to improve their artistic cultivation and aesthetic awareness, and use aesthetic vision to guide and evaluate the operation process and treatment results.
For example, the application of lumpectomy technology, small incision surgery or other minimally invasive technology, so that the correction of foot deformity and functional reconstruction without or less incision scar and retain the flexibility of the foot, is obviously the trend of surgical development. For example, our hospital carries out small incision foot deformity orthopedic surgery, bipedal and other large surgery, short foot lengthening, metatarsal lengthening beauty toe surgery, etc., to meet the young people’s pursuit of foot aesthetics.
5.Minimally invasive distraction technology brings the correction of foot and ankle deformity into the biological era
The tension-stress law discovered by Ilizarov and the three-dimensional external fixator pulling orthopaedic technology have revolutionized the correction of foot and ankle deformity, and soft tissue deformity correction can be achieved satisfactorily through slow pulling by only installing Ilizarov external fixator. In case of severe or complex bony deformity, rigid ankle deformity which failed or recurred in previous surgeries, 3D foot and ankle retraction orthosis can be installed after limited osteotomy, and the deformity can be satisfactorily corrected by slow retraction according to the requirements of deformity correction without significant pain to the patient after surgery, and serious complications can be avoided.
All soft tissues including tendons and ligaments are not loosened or severed, and good anatomical structure and function can still be retained after deformity correction. Ankle joints that have degenerated, narrowed and stiffened are fitted with retractors with hinge joints, so that joint activities can be performed with the ankle joint gap in a mildly separated state, which can restore some joint functions and avoid or delay the Ankle joint replacement or joint fusion is performed. Ilizarov technique meets the biological requirements and natural reconstruction concept.
6. The use of modern foot and ankle orthoses has delayed or reduced the scope of surgery
Due to the continuous development of new materials and processes, the structure and function of modern foot and ankle orthoses can achieve three roles: stabilizing the loosened joint, changing the weight-bearing stress and orthopaedics. Foot and ankle surgeons should pay attention to understanding and mastering the materials and functions, indications and new conformational features of foot and ankle orthoses. Some foot and ankle diseases and minor foot deformities can be improved significantly and the development of deformity can be prevented by fitting foot and ankle orthoses, thus avoiding surgery or delaying its implementation.
7.Conclusion
The changes in human bones and joints follow the basic law of stress and strain. The vast majority of acquired foot and ankle disorders, in addition to trauma and disease, come directly or indirectly from the unreasonable or cumulative stresses of upright walking. When did humans enter the stage of wearing shoes? What kind of shoes do adolescents and children wear and what kind of exercise pattern is conducive to the normal development of the foot? As the average life expectancy of human beings increases, how can the elderly take care of their feet and ankles in order to live a healthy life? How to evaluate the principles of correction of previous foot and ankle deformities by using evidence-based medicine?
Affluence and changes in lifestyle patterns have increased the incidence of foot and ankle disorders. From the perspective of biological evolution, social evolution and new body culture, we should explore the relationship between foot development, maturity and lifestyle, the occurrence, formation and transformation of foot and ankle injuries, deformities and diseases, reasonably evaluate and correctly apply various high-tech and natural reconstruction concepts, so as to study the correct anatomical values of foot and ankle bones and joints of 1.3 billion Chinese people, the evaluation criteria of deformity correction and the prevention and treatment guidelines of common foot and ankle deformities. It is the great responsibility of Chinese orthopedic surgeons, especially foot and ankle surgeons.