Fig. 17.1
A simple fracture with a complex associated soft tissue injury.The fracture was stabilized initially with an external fixator (a) to diminish the risk of prolonged surgery and implant-related infection. The muscular injury, however (b), resulted in extensive necrosis and the decision was made to amputate by both the patient and the surgeon.A successful transtibial amputation was performed, but soft coverage presented a technical challenge.
Often an amputation is presented as a definitive treatment option that will help avoid ongoing surgeries and hospitalizations in the interest of letting a patient “get on with his life.” In obtaining informed consent, however, the caregiver would be wise to counsel patients that amputations may require subsequent surgical procedures and may still result in debilitating challenges related to pain and potential residual dysfunction. Commonly, wound debridement with skin grafting or flap revision and excision of heterotopic bone growth or painful neuromas may be necessary. Salvage, on the other hand, may require prolonged efforts and significant costs and may ultimately prove futile. With traumatic injuries of the extremities, even in the setting of technically “successful” limb salvage, the functional result may be unsatisfactory. In Lin’s study of functional outcomes of lower-extremity fractures with vascular injury, even with salvage, every patient needed subsequent reconstructive surgery to achieve an acceptable functional result. Not surprisingly, the more severely injured limbs had poorer functional results [1].
Various factors will play important roles in the decision to choose a treatment course. These factors will include the pathologic process, the patient’s general condition and goals or expectations, the treating team available, and the individual caregivers’ expertise at all levels of care. Efforts have been made to help the treating team decide the predictability of salvaging a severely traumatized limb. Several amputation index scoring and rating systems were developed in attempts to try to assist the physician teams caring for severely mangled extremity injuries in deciding whether to attempt salvage or carry out primary amputations immediately after injury. These indexes were often based on the initial presentation of the extremity and often did not take into account unsuccessful salvaged limbs or functionally limiting salvaged limbs, which required a secondary amputation. There are several objective criteria which have been evaluated over the years and used to predict failure of limb salvage/high probabilities of limb amputation following lower-extremity trauma [2]. Some of the commonly utilized injury severity scoring systems include the Mangled Extremity Severity Score (MESS); the Limb Salvage Index (LSI) [3]; the Predictive Salvage Index (PSI) [4]; the Nerve Injury, Ischemia, Soft-Tissue Injury, Shock, and Age of Patient Score (NISSSA) [5]; and the Hannover Fracture Scale-98 (HFS-98) [6, 7].
Unfortunately, limb salvage scores were not shown to be successful at predicting the viability of a leg [8]. Additionally, lower-extremity scoring systems are not accurately predictive of the functional outcome of successfully salvaged limbs [9]. Ultimately, the advantages of a skilled and experienced set of caregivers produce the best option for the patient. Patients should be counseled regarding the risks and advantages associated with various treatment options.
Team management is preferable to disjointed care. Each team member should know his or her role and have a means of communication with other team members. An effective team will coordinate care in a way that involves and educates the other team members. Optimally, the team involves plastic, orthopedic, trauma, vascular, and podiatric surgeons as needed acutely. PM&R specialists, neurologists and pain management specialists, psychologists and psychiatrists, prosthetists and wound care specialists may play important roles that outlast surgical needs. Experienced nurses are invaluable. Physical therapists play a major role in optimizing the outcome. Quality care at each step is crucial, as an excellent prosthetist may be unable to compensate for suboptimal surgery, and vice versa. Outcomes and complications may be difficult to predict, and the accurate identification and treatment of secondary problems may be important in the patient’s achievement of a satisfactory lifestyle. The outcomes reported from the LEAP study were similar between salvage and amputation groups [8].
There are general principles in salvage and in amputation that help guide the decisions and treatment, irrespective of the etiology. Honesty and transparency help patients make appropriate informed decisions and allow them to play an active role in achieving their goals. Acknowledgments, where appropriate, of clinical uncertainty and the explanation of realistic expectations at all times help prevent subsequent misgivings and questioning of motives. Appreciation on the part of patients and caregivers alike of the psychological and emotional impact of a life-altering situation can be helpful. The practitioner can most certainly be a crucial contributor to the psyche of the patient and will, in less optimal circumstances, contribute to potentially preventable and predictable emotional challenges.
The Pathologic Process
The disease course that leads to a limb at risk, in need of treatment and optimization, can be quite remarkably varied. The two most common causes of amputation or need for reconstructive salvage efforts are traumatic and vascular in nature. Congenital and neoplastic causes remain less common. The incidence of infection leading to the need for intervention is less well established, because it may be a secondary outcome of trauma or a multifactorial host disease, such as diabetic peripheral vascular disease, making it difficult to tease out the etiology.
There will be fundamental similarities and differences in management in these different settings. In all circumstances, the goals of eliminating disease, minimizing pain, and maximizing function must be met. Socioeconomic factors and resource availability must be taken into consideration. The speed of recovery may be more crucial in certain patient populations, such as laborers, whereas maximal tissue preservation may be a priority in younger populations at the expense of more prolonged hospital course. Upper-extremity salvage for cosmetic reasons may be preferable to some patients, even where function is limited.
Vascular Etiologies
Nontraumatic vascular pathology is usually a progressive condition that affects an older population, often with concomitant comorbidities such as diabetes mellitus. The prevention of limb loss is focused on early disease identification and correction of reversible conditions, such as smoking and control of glucose levels. Less-invasive interventions, such as stenting, have proven effective, whereas arterial bypass has become less commonly performed.
The natural history of the disease process, however, tends to be unfavorable. Twenty five percent of patients with an amputation will undergo a contralateral amputation within 3 years. Mortality rates after amputation remain high. Nonambulators undergoing amputation may be indicated for transfemoral amputations for more distal disease to avoid the need for subsequent higher-level amputation surgery. On the other hand, most transtibial amputations have the capacity to heal, and a common error is to perform amputation more proximally than necessary in ambulators.
Various diagnostic modalities related to blood flow and oxygen delivery may contribute to the surgeon’s assessment of the proper level for an amputation and of the healing capacity, but none have demonstrated the ability to be independently predictive to the point of removing surgical experience and judgment. Amputations in vasculopaths are generally performed without tourniquet inflation, and postoperative compressive dressings in this patient population run the risk of causing further ischemia and catastrophic pressure necrosis.
Traumatic Etiologies
When one is considering the initial evaluation of traumatic injuries including the extremities, it is important to remember to adhere to the guidelines provided by the Advanced Trauma Life Support (ATLS) and as proposed by the American College of Surgeons (ACS), which emphasize “life over limb” by focusing on the ABC(DE)’s of care first. Other general principles with regard to the overall management of extremity injuries and salvage attempts include the general initial presentation of the patient and the extremity of concern.
Hypovolemic shock is a common occurrence with severely mangled extremities or polytrauma. This hypovolemia may compromise perfusion of the limb, whether from general global hypoperfusion or extremity-specific hypoperfusion. In the setting of extremity-specific hypoperfusion, general temporizing maneuvers to restore blood flow are used (i.e., temporary arterial shunts or definitive bypasses) depending on the estimated duration of ischemia [10]. Generally, it has been well established that after 4–8 h of “warm ischemia,” efforts at limb salvage are not feasible [11–13].
Where significant limb ischemia is not a concern, skeletal fixation may be desirable to provide limb stability, allowing for the vascular and soft tissue reconstruction efforts. Any question related to injury of an extremity warrants, at a minimum, radiologic evaluation with X-rays. Likewise, any question of compromise to an extremity requires evaluation with angiography if the initial or serial physical examination or Doppler examination shows compromise. Ankle-brachial comparative pressure measurements may be predictive of a possible need for revascularization.
A few basic definitions and concepts need to be established prior to tackling the problems of traumatic extremity pathology. A mangled extremity is commonly understood to be a limb that has at least three out of the four tissue groups damaged: the soft tissue, nerves, vasculature, and bone [14]. There are several grading systems used to categorize a mangled extremity, and these grading systems have various correlations with overall outcomes with and without reconstruction and have even been used in the decision-making tree for deciding limb salvage potential versus amputation, without mandating or predicting which if either should be performed. Earlier debridement of mangled extremities is the goal for potential salvage of the best functional outcomes and limb salvage.
The general teaching of timing and sequence of acute limb salvage as taught during training is as follows: thorough debridement (as early as possible), bony stabilization and revascularization, tendon and nerve repair, and soft tissue repair and coverage [15]. There is inconclusive evidence that bony repair and fracture stabilization should precede definitive vascular reconstruction for fear of damage to the newly established vascular anastomoses. It is often preferable to perform final nerve reconstructions and transfers as well as tendon and bone grafting once wounds are clean and ready for final flap/muscle coverage.
Orthopedic Care
The management of complex limb injuries or limbs at risk for amputation requires restoration of stability and recovery of function. This can necessitate fracture fixation or stabilization after excision of compromised bone. Loss of stability can cause deformity and limb shortening under the effects of muscle contraction, which occur involuntarily. Also, an ongoing injury to the soft tissue envelope can compromise neurovascular structures, and muscle and skin necrosis can result as well. At times, reconstructive efforts may necessitate the treatment of these specific complications.
Maintaining the length of a destabilized bone or joint can be achieved in a variety of ways. Splinting and casting may be inadequate to maintain length and alignment and prohibit early range of motion following an amputation, often making internal methods preferable. Implants are selected for their ability to provide effective stability and to optimize the mechanical and biological environment. In long bones, such as the tibia or femur, the midshaft fractures can be effectively managed with intramedullary fixation. The advantages of intramedullary fixation include aligning the implant with the anatomic axis of the bone, thus diminishing forces due to bending moments. Furthermore, the surrounding soft tissues are not in contact with the implants, resulting in less potential irritation of the surrounding muscles, fascia, and skin. Periarticular fractures, on the other hand, are typically treated with plates and screws. Current implant designs are geared toward optimizing the implant fit with regard to the contour of the bone, thus minimizing irritation.
In an extremity with an elevated risk of infection, the application of metal stabilization implants may complicate matters. It is well established that infections compromise fracture stabilization implants such as plates and screws as well as prosthetic joint implants. The bacteria in this setting are able to establish a protective “biofilm” or glycocalyx barrier that is protective to the effects of systemic antibiotics, diminishing the efficacy of the antibiotic by a factor of 1000 [16]. In this setting, the eradication of infection often necessitates the removal of the implant, again destabilizing the extremity. Thus, introducing “permanent” implants in the setting of a compromised wound or host is highly risky.
The recommended management of a fracture or bony defect at high risk, therefore, often includes temporary or definitive external fixation. In this approach, percutaneous rigid pins and transosseous wires anchor the bone proximal to and distal to the involved region (Fig. 17.1). External to the soft tissue envelope, these pins and wires are connected by longitudinal bars and clamps. This modality commonly leaves implants more remote from the zone of injury, and if the component of the device (i.e., a pin or wire) becomes locally infected, it is easily removed or replaced. The local infection rate of the individual pins and wires can be quite high in more prolonged applications. Optimally, temporary stabilization is achieved, and the region is treated with appropriate bone and soft tissue care to optimize the local biology, allowing conversion to definitive internal fixation.
Bone defects can often be treated with bone autograft (Fig. 17.2), allograft, or, bone graft substitutes (typically osteoconductive and/or osteoinductive materials that stimulate bone growth), with various options to augment healing, such as bone marrow osteogenic cell transfer or bone morphogenetic proteins [17].
Fig. 17.2
A 26-year-old male motorcyclist sustained an open distal femur fracture dislocation with significant bone loss (a). External fixation (b) with soft tissue healing was succeeded by plate fixation and bone autografting (c). The patient went onto fracture union (d) with no additional complications
Presently, a vast industry has developed in the field of bone products and bone void filler products [18]. The user of these products should be aware of the advantages and disadvantages of the various products available and of how financial factors in this marketplace can influence decisions and cause additional confusion [19].
Vascularized bone grafts may be appropriate in certain settings, where nonvascularized grafts have failed or are more susceptible to infection (Fig. 17.3). Further, vascularized bone grafts may be a component of a tissue transfer procedure that includes soft tissue coverage. Vascularized bone grafting is a technically challenging microsurgical procedure that requires expert judgment and skills and involves additional surgical risks to the patient at the donor site, typically remote from the bone defect site. This may temporarily confer additional debility to the patient (Fig. 17.3).
Fig. 17.3
A 29-year-old male with a history of leukemia and hip osteonecrosis following radiation. Subsequent to hip replacement for the osteonecrosis, he was assaulted and sustained a periprosthetic femoral fracture (a). Following plate fixation (b), he developed a nonunion. Upon surgical exploration, it was noted that he had dysvascular bone at the fracture site, which precluded healing. The bone was resected, the plate was revised, and a temporary cement bone spacer was placed (c). A vascularized fibula graft was inserted into the defect and this incorporated, enabling successful bony union (d)
Finally, “bone transport” is a modality that can be very effective in bridging bony voids. This is a technique that typically uses a specially designed external fixator (although internal fixation options have been designed) to slowly move a healthy segment of the bone across a defect and grow new regenerative bone in the void. This technique can be very effective even in a compromised host or in compromised local biology but is time-consuming and labor intensive for the surgeon. Typically, the bone is moved up to 1 mm/day, and the new bone growth often takes three times as long as the “transport” of the bone takes.
This modality is very time intensive for the practitioner and may be fraught with challenges for both the surgeon and the patient. Complication rates are high, including risks of infection, neurologic injury, and joint stiffness, but success rates can be excellent when technique and judgment are good. In contrast with most temporary external fixators, the constructs assembled with definitive external fixation and bone transport are designed to last longer and may often be sturdy enough to bear weight during the process (Fig. 17.4).
Fig. 17.4
A 54-year-old male with a history of smoking fell from a ladder with a resultant open distal tibia “pilon” fracture (a). He underwent initial irrigation and debridement with external fixation, but developed a deep infection with the skin and bone loss due to extensive local necrosis. This required resection of the tissue, muscle flap coverage, a cement spacer with antibiotics (b), and systemic antibiotics. The residual bone loss and tissue compromise were treated with a circular external fixator and bone transport. In (c), the external fixator components reveal the extensive nature of the device. The proximal osteotomy can be seen. Following bone transport (d), the proximal regenerative bone at the osteotomy site is seen, and the distal defect is eliminated with bone healing (e)
A limb length discrepancy (LLD) may be treated nonsurgically, with a customized in-shoe orthosis or with shoe modification. Surgical management of LLD is usually reserved for discrepancies greater than 1 inch. In growing, skeletally immature patients, the opportunity to match limb length through surgically treating the contralateral limb exists. This is done by arresting the growth in a predictable manner on the contralateral limb through a process termed epiphysiodesis. This involves the surgical ablation of a growth plate or physis. In mature patients, this option does not exist, but selective limb shortening of bones may be an option. The amount of shortening a limb can tolerate may be 2–3 inches, depending on the bone and the size of the patient. Muscle weakness may complicate this technique due to a loss of tension generated in affected muscle groups. Limb lengthening can be performed in adults in a manner similar to the process of bone transport. To lengthen a shortened limb, the bone can be osteotomized and lengthened via a progressive distraction at the osteotomy site. This technique is known as distraction osteogenesis.
Any fracture or osteotomy site will require bony union. The amount of time a bone requires to unite is a function of many variables. Host factors, such as patient age, nutrition, prior and current medical conditions, medications, and tobacco use, often have an influence on fracture healing. Anatomic site will also be relevant. Distal tibia fractures heal notoriously slowly, whereas midshaft humeral fractures commonly heal in half the time on average. Fixation methods may also play an important role in bone growth and healing. Excessively rigid fracture fixation, for example, may inhibit the growth of the bone across any gaps. Insufficient stability, by contrast, will promote bone growth but may still result in nonunion, and alignment control may be sacrificed as well. The ideal stabilization environment may thus be an elusive concept, even for experts in the field of fracture fixation with extensive knowledge of bone biology and biomechanics.
In addition to bony sites of injury or instability, joints may develop laxity or excessive pathologic motion through traumatic, inflammatory, degenerative, or other pathologic processes. Stability is conferred through joint articular congruency and soft tissue constraints that may include the joint capsule, labral tissue, ligaments, and musculotendinous dynamic compressive forces. Our appreciation of factors affecting joint stability is continuing to evolve. Although joint laxity alone is not a limb-threatening process in most patients, when combined with other pathologic elements, this may become a serious problem. Joint instability may preclude functional recovery and may put the patient at risk for other complications, such as recurrent or further injury, or compromise other structures through reinjury or additional falls. Management of joint laxity may include nonoperative modalities such as temporary or definitive immobilization or bracing. Operative options may include external fixation options (which include hinged external fixators that allow normal motion) and soft tissue repair or reconstruction.
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