Very few subspecialties of orthopaedic surgery have experienced as marked an evolution as the field of limb-sparing surgery in the past 30 to 40 years. What used to be a routine amputation treatment for a variety of conditions can currently be, in many instances, treated by a limb-sparing surgery. Even when amputation is necessary, the current techniques frequently allow for the creation of more functional, more distally amputated residual limb. The advances in imaging (MRI, CT), surgical techniques such as microvascular surgery, external fixators’ techniques, nerve repair, increased sophistication of internal fixation and vacuum suction dressing for complex wounds, to name just the most important ones, have opened a field for innovative techniques of limb salvage and reconstruction.

In addition, a wide availability of allograft tissue, especially bone, the advent of commercially available biologic modifiers of bone healing such as bone morphogenetic proteins, and advances in the fields of anesthesia and resuscitation have further contributed to the evolution of limb-sparing surgery.

Although it was probably management of malignant tumors of the extremities that led the way in limbsparing surgery, these techniques are now widely used in any situation where the limb is at risk, such as trauma, infection, vascular abnormalities, and in children with congenital limb deficiencies.

Congenital limb deficiencies in children are more frequent and have less specialized care in developing countries.¹ These inequalities and imbalances are highlighted by epidemiologic data and surveillance records of the various countries, and have been reported and analyzed by the World Health Organization.^2,3 The monumental compendium Congenital Malformations by J. Warknay, dealing with the etiology and clinical manifestations of congenital diseases, is considered to be a milestone not only for the field of teratology but for the whole human biology.^4,5 Congenital limb deficiencies comprise most abnormalities requiring specialized care, to which will be added posttraumatic, vascular, and infectious conditions. Therefore, it is important to always refer to the history of teratology and to the current knowledge of embryo teratology and teratogenesis. Knowledge of the anatomy of congenital limb deficiencies, their classification systems,^6,7,8,9,10 and the embryo-teratogenic development^11,12 are important references to guide the choice of treatment and improve care.^13,14,15

Despite the aforementioned information, amputation remains the procedure of choice in many instances. Insensate, poorly perfused, functionally useless reconstructed limb is a poor alternative to properly selected and performed amputation and modern prosthetics fitting.

The best procedure for a given problem or situation depends on multiple factors, both objective and subjective. Age and skeletal maturity in children, etiology of the affliction, anatomic involvement, comorbidities, and overall life expectancy of the patient are objective criteria. Functional demands and
cultural and psychological acceptance of a given procedure are of a nature that is more subjective. The availability of specialized surgical expertise, modern medical technology, and specialized prosthetic and orthotic services will also play a significant role in a given procedure choice.

Even when amputation, either terminal or intercalary, is required, various limb salvage techniques can be used to make the residual limb more functional. In this sense, the anatomy of congenital limb deficiencies and the study of experimental models of such deficiencies are of fundamental help.^{6,7,8,9,10,16,17,18}

It is imperative to help the reader in the decision making regarding the best approach to a given problem, based on objective principles and published outcome studies.

The etiology of amputations is different between adult and pediatric patients (Table 1). In adults, most amputations are performed for complications of peripheral vascular disease, followed by trauma and tumors. The most frequent causes of amputation in children are congenital limb deformities, tumors, trauma, and infections. Other rare conditions are less common. In children as well as in adults, causes of amputations show regional variations and can vary with the type of socioeconomic conditions of each region.^{19,20,21,22,23,24,25,26,27,28,29,30,31,32,33} In this respect, a more up-to-date approach to the most frequent causes of amputation in children as congenital limb deficiencies, tumors, trauma, and infections must also consider the socioeconomic reality of the patient.¹

Skeletal growth and potential for remodeling have a significant effect on the outcome of both a pediatric amputation and a limb-sparing surgery, particularly in the younger child. For example, a very young child who undergoes an transfemoral amputation will have an extremely short residual limb at skeletal maturity because of the loss of the distal femoral physis, causing a loss of approximately 1.2 cm per year until the end of growth. Similarly, a 10-year-old child who has a successful total femur endoprosthesis will have a lower limb discrepancy at maturity because of the loss of both proximal and distal femoral physis of the affected leg and the continuing growth of the contralateral limb. Remaining growth must be taken into account when limb-sparing surgery or amputations are planned so as to provide the best esthetic and functional outcomes as children have higher functional demand compared with adults (who are more sedentary are often more overweight).

Stunted growth, painful overgrowth, and growth disturbances such as limb shortening and/or limb deviation can develop in children. Moreover, treatment can be lengthy with significant psychological consequences. In some cases, treatment can last several years, thus leading young amputees and their caretakers to face decades of potential pain, psychological consequences, and difficulties with daily life activities such as eating, playing, and doing schoolwork. In some other cases, when neoplasms are the cause of amputations, the emotional aspect is particularly important because of the evolution of the disease and the expectations of surgery.^{19,20,21,22,23,24,25,26,27,28,29,30,31,32,33} The context presented previously, and partly analyzed, is broad and difficult. However, it is an opportunity to consider and take note of the multiplicity and richness of the scientific achievements of recent decades, which have made it possible to face complex situations, solve difficult problems, and find methods and solutions that were judged to be at the limit of the possible, for example, the unthinkable rebirth of many amputees and the success of the Paralympic Games that has made everyone aware of the incredible lives of so many young amputees.

Vascular amputations are almost exclusively performed in adult patients. In the adult age group, major causes of amputation are diabetes and/or peripheral arterial disease resulting in painful limb, poor limb perfusion, untreatable ulcers, or gangrene (with or without infection). The prevalence of peripheral arterial disease in the general population ranges between 12% and 14%, affecting up to 20% of adults older than 70 years. In this situation, the emphasis is primarily on prevention of ischemia by medical and surgical means. Once a limb becomes nonviable, standard amputations such as transtibial and transfemoral are usually used.

Traumatic amputations are more frequent in adults compared with children.

In children, amputations secondary to trauma represent approximately 5% of all injuries. Every year, approximately one-third of traumatic amputation injuries occur among children younger than 18 years.^34,35 Approximately 80% of all
amputations affect the lower limb with the remainder in the upper limb,^36,37 and most cases of major amputations following trauma in children involve the lower extremity, in particular the tibia. More than 95% of amputations secondary to trauma in children equally affect the foot or toes and the hand or fingers.³⁸ Hostetler et al found most traumatic amputations involve fingers caught in closing doors in children (predominantly males) younger than 2 years. However, such amputations are often minor and, in most cases, do not compromise upper limb function. Older children, preadolescents, and adolescents experience a higher proportion of more serious amputation injuries, mostly related to high-energy trauma (lawn mower accidents, bike, motorbike, and road traffic accidents). In particular, studies have found that road traffic accidents are responsible for approximately two-thirds of amputations in older children.^36,37,38 Those percentages are significantly higher in adults. In children, skeletal immaturity predisposes to higher rate of complications such as terminal overgrowth.^39,40 However, such complications are less severe in the pediatric populations compared with adult patients.