Hip Disarticulation and Hemipelvectomy in Children: Surgical and Prosthetic Management

Joseph Ivan Krajbich MD, FRCS(C)

Todd DeWees MHA, CPO

Dr. Krajbich or an immediate family member serves as a board member, owner, officer, or committee member of Scoliosis Research Society. Neither Todd DeWees nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

ABSTRACT

Hip disarticulation and hemipelvectomy (transpelvic amputation) are uncommon in pediatric patients. However, in acute situations, it is helpful to be familiar with the surgical approaches and prosthetic options for children undergoing high-level lower limb amputations. Classification based on etiology may affect overall patient management. The components available for prosthetic fitting may be limited based on the age of the patient.

Introduction

Pediatric amputees represent between 10.3% and 11.7% of the overall amputee population.¹^,² Patients with hip disarticulations and hemipelvectomies (transpelvic amputations) represent approximately 2% of the amputee population.¹ Therefore, pediatric patients with high-level lower limb amputations represent only 0.2% of the overall amputee population. Because of the very small number of children with hip disarticulation or hemipelvectomy, surgeons and prosthetists often have limited experience in treating these patients, who have special needs and require special considerations. It is likely that only tertiary referral centers for pediatric limb deficiency treat enough of these children to collect adequate objective data to establish both surgical and prosthetic treatment principles. Besides congenital absence of the lower extremity (amelia) or rare instance of other complex congenital abnormality, the traumatic injury, sepsis, malignant neoplasm, and vascular malformation are among the main etiologic causes of these high-level amputations. Consequently, virtually any practicing orthopaedic surgeon can face an acute situation where hip disarticulation or hemipelvectomy is necessary to save the life of a child. It is therefore important to be familiar with the basic management principles that guide treatment and prosthetic fitting to provide these children with optimal care.

Surgical Management: Anatomic Considerations

In most instances of acquired highlevel amputation, the surgical treatment is likely to be dictated by the type of injury or the condition leading to the amputation. Therefore, the surgeon should be well versed in the anatomy and the surgical exposures around the hip and pelvis and be able to adapt the approach to the individual circumstances.

Children usually have a healthy proximal blood supply, resilient tissues, and good healing potential. All three main blood supplies to the proximal part of the limb can be used as dictated by the circumstance. A posterior gluteal flap based on gluteal vessels, an anterior flap based on external iliac/femoral vessels, and a medial flap based on the obturator vessels can all be used. It is important to be aware that the bony pelvis and the proximal femur serve as attachments to a host of central skeleton muscles. Their loss or loss of their anchorage can lead to secondary issues related to pelvic floor support, abdominal wall integrity, and spinal balance.

The pelvis is also the site of several internal organs whose preservation or removal will depend on the existing pathology and surgeon’s skill. Because a procedure of this magnitude will have a substantial effect on the patient’s quality of life and future health, an intimate knowledge of the underlying pathology and pelvic anatomy is imperative. Not infrequently, a multidisciplinary team consisting of an orthopaedic surgeon, pediatric general surgeon, urologist, vascular surgeon, and even a plastic surgeon is called on to maximize safety of the procedure and preservation of organs and tissue. The goal is to optimize recovery potential with the maximum residual function attainable under the circumstances. In rare circumstances when neurovascular supply to the distal part of the extremity is preservable and the distal part of the extremity
itself is relatively uninvolved by the pathologic process, more complex reconstructive procedures can be attempted (rotationplasty, tibia to pelvis fusion, or articulation).

Terminology and Classification

Hip Disarticulation

In general, in hip disarticulation, it is assumed that there is loss of the bony structures distal to the pelvic side of the hip joint. That is, all of the femur is absent, but the pelvis, including the acetabulum, is intact and present. The integrity of the soft tissues can vary with etiology. A special case is the presence of a very short femoral segment that cannot serve as a functional proximal femur for the purpose of prosthetic fitting. In such instances, the child will likely require a hip disarticulation-like prosthetic fitting. This is a relatively important point. In a very young child facing transfemoral amputation, the loss of the distal femoral epiphyseal plate will lead to insufficient growth in the remaining femur and may preclude a functional transfemoral prosthetic fitting when the child becomes older. Such a child may eventually require a hip disarticulation-like prosthesis (Figure 1). In some congenital deficiencies, such as phocomelia, a hip disarticulation-like prosthesis may be required if the vestigial limb cannot provide enough function to support transfemoral amputation-like prosthesis. Despite this, every effort should be made to preserve as much length of the proximal femur as possible. Even relatively small fragment can potentially be lengthened in the future as long as there is an adequate soft-tissue envelope. Even modest proximal femoral lengthening may lead to a better anchor for a prosthesis.

FIGURE 1 AP radiograph of the pelvis of a child with right-sided phocomelia. The patient will be fitted with a functional hip disarticulation prosthesis.

Hemipelvectomy

Partial or complete hemipelvectomy is also called transpelvic or hindquarter amputation. The limb loss involves not only the whole limb but also a portion of the central skeleton (the pelvis and potentially pelvic organs). Congenital deficiency of this magnitude is not unheard of but clearly very rare (Figure 2). Even acquired deficiency is quite uncommon. Malignant tumor, acute trauma, or rarely surgical separation of pygopagus conjoined twins are among the causes of this radical intervention. The complexity of the surgical approach, if needed, and prosthetic fitting depend on the presence and integrity of the remaining bony pelvis, the soft-tissue structures, and the underlying pathologic process. The extent of amputation can vary from a limb removal, including only a portion of the bony pelvis, to complete hemipelvectomy, including part of the sacrum and part or all of several pelvic organs (gastrointestinal tract, lower urinary tract, and reproductive organs) (Figure 3). In such a situation, it is mandatory that a well-coordinated team of several surgical subspecialists is assembled to achieve an optimal outcome. When possible, careful planning of the procedure should be undertaken to optimize the achievement of the primary goal of the surgical procedure, which is complete control of the disease process (adequate surgical margins in the case of malignant tumor resection) yet allowing for an optimal anatomic and functional result. Especially in very young children, future additional surgical intervention(s) and potential prosthetic fitting will very much depend on the presence of any preserved skeletal and soft-tissue elements.

FIGURE 2 Congenital deficiency of the hemipelvis. (Courtesy of Joseph Ivan Krajbich MD, FRCS(C), Portland, Oregon.)

Classification According to Etiology

Similar to other limb deficiencies in children, high-level lower limb loss can be either acquired (trauma, neoplasm, or sepsis) or congenital (amelia), phocomelia (intercalary deficiency), or another type of loss (conjoined twins).

Trauma

Trauma likely accounts for most high-level amputations in the lower limbs. Motor vehicle crashes (the child is usually a pedestrian), lawnmower injuries, and injuries sustained in a war zone are high-energy injuries that devastate the proximal soft tissues. Frequently, these injuries are complicated by massive wound contamination and loss of bony integrity. Because these are serious, life-threatening injuries, resuscitation of the child by establishing cardiopulmonary stability is the first priority. Stopping major blood loss is an integral part of this effort. Initially, simple manual pressure and packing is all that can be done. After the patient’s condition has stabilized and adequate ventilatory support and fluid resuscitation have been accomplished, careful assessment of the extent of the injuries is necessary for a rational approach.

Surgical control of major bleeding and débridement of contaminated tissue is the next mandatory step. At this point, the treatment
team must decide if any emergent limb salvage procedure can be used. Revascularization is an important consideration because a relatively short window of a few hours exists in which an avascular limb can be saved. Attempts should be made to preserve and use any relatively intact and viable tissue to increase the length of the limb and diminish functional loss. As already mentioned, the ability to preserve the distal femoral physis can be of major importance in the functional outcomes of very young children. A major impediment of instituting such reconstructive procedures in the setting of acute trauma is the absence of an onsite specialized surgical team. Transfer of the child to an institution with these capabilities should be considered if feasible.

FIGURE 3 Pelvic anatomy. Any of these structures can be involved in as significant pelvic trauma or pelvic neoplasm. (Reproduced with permission from Anatomical Chart Company © Wolters Kluwer. All right reserved.)

Additional interventions can be instituted after the patient is stabilized. Treatment by experienced surgeons in an operating room setting may lead to more judicial débridement and may optimize the survival of remaining tissues. A number of débridements with the wound remaining temporarily open or managed with vacuum suction dressing may be necessary before final wound closure. Any needed bone or soft-tissue reconstruction can be part of this process.³^,⁴^,⁵

Additional techniques can be used to obtain optimal functional results for each patient. Bone transport, rotationplasty, free flaps, rotational flaps, and composite vascularized graft all can be used.⁶^,⁷^,⁸^,⁹

Neoplasms

In children, Ewing sarcoma is the most common neoplasm found in the proximal femur or pelvis; however,
osteogenic sarcoma and some soft-tissue sarcomas also occur at these sites. Among the soft-tissue sarcomas in children with neurofibromatosis type 1 (von Recklinghausen disease), peripheral nerve sheath sarcoma is the most frequently encountered neoplasm.

Because modern management of these tumors has shifted toward chemotherapy and limb salvage, a primary amputation is performed only in a situation in which limb salvage is not possible because of the involvement of vital structures and inability to otherwise obtain clear resection margins.¹⁰^,¹¹^,¹²^,¹³^,¹⁴^,¹⁵ Primary amputation is a relatively rare treatment in a modern pediatric oncology surgical practice. In the experience of one of this chapter’s authors (JIK), primary amputation is most likely in a patient with pelvic neurofibrosarcoma. This neoplasm is resistant to chemotherapy and radiation therapy and frequently involves several vital structures in the pelvis; a complete hemipelvectomy is often the only chance for a cure. Failure of a primary limb salvage procedure, such as endoprosthetic or allograft replacement in the femur or internal hemipelvectomy on the pelvic side, is another situation where hip disarticulation or formal hemipelvectomy may be required. Substantial postoperative complications are possible.¹⁵^,¹⁶^,¹⁷

Sepsis

Purpura fulminans septicemia, necrotizing fasciitis, and other causes of infected gangrenous limbs may necessitate proximal limb amputation as a lifesaving measure.¹⁸ The surgical principles used to manage septic shock will apply. Cardiopulmonary resuscitation, fluid resuscitation, the administration of massive doses of antibiotics, and débridement of any obvious necrotic contaminated tissue are also critical to the patient’s survival. However, the need for an emergent proximal amputation usually does not apply in patients with purpura fulminans. Associated systemic sepsis generally leads to ischemia of various body parts, which quite commonly includes the limbs. In this situation, limbs or parts of a limb can become ischemic but are not contaminated by infection (dry gangrene). In such a situation, it is necessary to wait until the final demarcation of necrotic and viable tissue occurs before deciding on the level of amputations. This final demarcation may take several days or even weeks and is usually quite distal to what may initially appear. Very proximal amputation is rarely necessary.

In any of these situations, the usual course of treatment involves multiple débridements and delayed wound closure until a healthy, uninfected wound is obtained. Modern, complex wound care techniques, such as vacuum-assisted dressings, flaps, and skin grafts, are usually used to achieve wound closure.⁴

Congenital Defects

Unilateral Congenital Absence of the Whole Limb

Unilateral congenital absence of the whole limb, also known as amelia, is a rare condition (Figure 2). The treatment mainstay is prosthetic fitting determined by the extent of the pelvic involvement. Surgical intervention is limited to the treatment of secondary effects of such a limb deficiency.

Phocomelia

Lower limb phocomelia is not technically a hip disarticulation. Quite frequently, however, a small deficient, minimally functional foot contributes little to limb function other than perhaps acting as an improved anchor for a prosthetic socket. Children with lower limb phocomelia frequently require hip disarticulation-like prostheses. Surgical intervention is rarely indicated unless the position or alignment of the affected limb at the pelvis interferes with prosthetic fitting. In such patients, a realignment procedure may be indicated. Many of these children have other limb deficiencies and warrant an individualized approach to maximize their function.

Separated Conjoined Twins

Pygopagus conjoined twins (Siamese twins) may be candidates for a separation procedure. After separation, either one or usually both children will have a hemipelvectomy-like situation. Separation is a very complex surgical procedure performed by a multidisciplinary surgical team, and it usually requires double teams of general pediatric surgeons, pediatric urologists, pediatric orthopaedic surgeons, and pediatric plastic surgeons. The soft-tissue defects can be quite large and may require prolonged treatment before the child is ready for prosthetic fitting.

Hemipelvectomy in Very Young Children

The absence of a hemipelvis has a substantial influence on the development of a child’s spine and contralateral hip. The loss of abdominal wall integrity, paraspinal muscle integrity, and iliopsoas integrity all lead to early paralytic-like lumbar scoliosis convex to the side of the absent hemipelvis. The remaining hemipelvis is at the caudal end of the scoliotic curve and tilts into abduction. Consequently, the remaining hip is forced into an adducted position with respect to its acetabulum. This leads to uncovering of the femoral head and, in a young child, the development of further hip dysplasia and eventually hip subluxation. Both surgical and prosthetic techniques are needed to treat these patients (Figure 4).

Initially, prosthetic treatment incorporates a spinal brace into the prosthetic design (Figure 5). However, a progressive worsening of the deformity may require surgical management. Surgical management of scoliosis and/or osteotomies around the hip, on the femoral as well as the pelvic side, may be required. In some of these children, other organ deficiencies and their management (eg, colostomies and other enterostomies) can make treatment even more challenging. A child with a colostomy or enterostomy on the prosthetic side may be more functional without a prosthesis; a walker or crutches and a swing-through gait may provide more effective locomotion.

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