Introduction

Extremity injuries involving significant trauma to bone, soft tissue, and major vessels are relatively uncommon outside of the wartime setting. This constellation of injuries may also be referred to as the mangled extremity. Much of the difficulty encountered in managing patients with a mangled extremity is due to the fact that few surgeons gain much experience in dealing with this challenging injury pattern. In order to meet this challenge, such injuries are best dealt with by a multidisciplinary team that combines the subject-matter expertise of vascular, plastic, and orthopedic specialists. The purpose of this chapter is to consider the nature of the extravascular component of severe limb trauma, the priorities in reconstruction, and the sequencing of interventions in order to furnish the vascular surgeon with the key imperatives of soft-tissue and skeletal management as understood by their orthopedic and plastic surgical colleagues.

Epidemiological Factors

The likelihood of fracture-associated extremity vascular trauma depends on the nature of the associated orthopedic injury; in a recent review the overall incidence was estimated to be less than 1%. However, certain orthopedic injury patterns, such as posterior knee dislocation, mandate a higher index of suspicion. Vascular injuries may be more commonly associated with fractures in the high-energy ballistic and blast environments of military trauma. From a database of 679 patients with military extremity trauma, Brown et al identified 34 patients and 37 limbs with vascular injury. In only 9 of these limbs was the vascular trauma not associated with a corresponding fracture. The authors of this study noted that outcome was worse in patients with combined orthopedic and vascular injury, and this was attributed to the unfavorable soft-tissue sequelae of energy transfers sufficiently large to cause bone fracture. This finding is also consistent with examples of high-energy extremity wounds reported in the civilian literature. In an Israeli report of 35 casualties, both military and civilian, Romanoff revealed that of 35 combined orthopedic and vascular injuries, 14 (40%) involved the femoral vessels, 9 (26%) compromised the popliteal vessels, and 8 (23%) involved the brachial artery. Upper limb injury complexes were often related to gunshot wounds compared to lower limb injuries. In Brown’s series (reporting experience from the British military), 11 injuries (30.5% of all cases) involved the upper limb, with 7 involving the brachial artery, and 4 involving the radial and/or ulnar arteries.

The orthopedic injury most commonly associated with a vascular injury is dislocation of the knee, particularly when the dislocation is posterior in nature. The orthopedic injury is of relatively low priority in the initial management of the patient as the knee will usually be easy to reduce and, in some cases, may have been reduced before the vascular injury is appreciated. In general, the majority of these will be closed injuries. In a literature review totaling 245 knee dislocations with a 32% incidence of vascular injuries, time to revascularization was the most important factor in determining outcome. The authors described a salvage rate of 89% when this was carried out in less than 8 hours, compared to an amputation rate of 86% when the delay was greater than 8 hours. A more-recent prospective report, undertaken as part of a multicenter study depicting the outcome of severe lower limb injuries described 18 patients, of whom 4 (22%) required amputation (a figure that is relatively consistent in the literature). Despite successful salvage, patients still had a moderate to high level of disability 2 years after the injury; the knees were stiffer and weaker; and only 2 were stable in all directions.

Grading of Orthopedic Fractures

Open fractures represent a heterogeneous group of injuries, but the relationship between extent of tissue damage and likelihood of limb salvage and functional recovery has been recognized for decades. As such, a formal system for grading the severity of open fractures was introduced by Gustilo and Anderson in 1976 ( Table 22-1 ). This remains a universally accepted classification of the wound associated with an open fracture, relating especially well to the risk of infection. For Gustilo type I fractures, an infection rate of 1% or less can be expected; and for type II fractures, a rate of approximately 3% has been reported. Since the original description, it has been recognized that those with type III fractures are a large and heterogeneous group; and, to reflect this, a modification to the original grading was made with subdivision of type III fractures as follows:

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  Type IIIA—Adequate soft-tissue cover of the bone despite extensive laceration

  
  
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  Type IIIB—Extensive soft-tissue loss, with periosteal stripping and exposed bone. Usually associated with massive contamination

  
  
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  Type IIIC—Open fracture with vascular injury that needs repair

For type IIIA fractures, an infection rate of 17% has been reported, and for type IIIB 26%. Type IIIC fractures have a variable infection rate, depending on the soft-tissue injury and the time to revascularization. A proportion of IIIC injuries require amputation due to lack of reconstructive options, and late infection is of less relevance as an outcome measure in this group. In a report of 546 tibial fractures, 7 of 9 IIIC injuries required amputation. The relative rarity of these injuries, combined with their heterogeneous nature means that meaningful comparison of outcomes (either between different papers or even between patients reported in the same paper) is difficult, if not impossible.

Salvage Versus Amputation

In essence only the following three decisions are available to the surgeon managing an extremity injury where limb ischemia is present: perform primary amputation, defer primary amputation to a later date, or attempt surgical intervention with a view to limb salvage. The latter may involve a lengthy or complex revascularization procedure, definitive fracture fixation, and soft-tissue coverage extending to microvascular tissue transfer. There are inherent risks of attempted limb salvage as the procedures may be costly in terms of patient reserve and risk of mortality, need for multiple operative procedures, and prolonged rehabilitation.

“Successful limb salvage” is a subjective phrase; outcomes can be variably defined according to patient factors such as pain, function, return to work, and satisfaction. Expectation of recovery varies according to the individual. Younger patients tend to have higher levels of preinjury activity, and rehabilitation will be concordantly longer in order to ensure recovery to previous functional capability. In contrast, the older, less-mobile population may have lower expectations. Expectation management forms a key part of the duty of the multidisciplinary team in cases of limb salvage or amputation, with regular and consistent counseling of the patient and their relatives in order to allow realistic but positive interpretations of recovery potential.

Studies have reported the long-term outcomes and quality of life in limb-salvage patients with open tibial shaft fractures and severe soft-tissue loss compared to amputees. Limb-salvage patients took longer to achieve full weight-bearing status, were less willing or able to work, and had a significant loss in range of movement at the ankle. Fairhurst et al demonstrated that early amputees had higher functional scores, fewer operations and returned to work and sporting activities within 6 months. They concluded that early amputation was better when confronted with a borderline salvageable tibial injury. However, recent reports from a prospective multicenter trial of 556 patients (the Lower Extremity Assessment Project [LEAP]), reported no difference in functional outcomes between patients who either underwent limb-salvage surgery or early amputation at 2-year and 7-year follow-up points. The level of amputation was a further predictor of outcome. Further analysis of the difference in cost analysis of limb salvage, and amputation has shown that the latter is significantly more expensive if the ongoing maintenance and replacement costs of the prostheses are included.

Several scoring systems have been developed to help guide the decision as to whether or not to amputate after severe lower limb trauma, and they have been designed to augment subjective clinical impression with objective assessment based on specific criteria. In their retrospective review of 58 severely injured limbs, Bonanni et al showed low sensitivities of Mangled Extremity Severity Score (MESS) (22%), limb-salvage index (61%), and predictive salvage index (33%). The LEAP study assessed MESS, predictive salvage index, limb-salvage index, nerve injury; ischemia/soft tissue contamination; skeletal; shock; age (NISSA), and Hannover Fracture Scale (HFS)-97. The authors reported a high specificity but much lower sensitivities for the scores than those reported by the developing authors. The performance decreased further when immediate amputations were excluded. A further study from the same group suggested that lower limb extremity scores do not predict the short- or longer-term functional outcome.

Strategies in Managing the Severely Injured Limb

Sequencing of Interventions

Considerable debate has centered on the sequencing of operative steps in the management of the mangled extremity. The following elements of treatment are necessary for most limbs that exhibit an open fracture associated with major vascular injury:

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  The extent of soft-tissue damage, vascular compromise, and skeletal instability must be systematically assessed.

  
  
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  The wound should be débrided so that all unviable tissue is removed.

  
  
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  Vascular repair/reconstruction should be performed.

  
  
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  Skeletal stabilization must be performed.

  
  
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  Mitigation of complications—such as infection or compartment syndrome—must be undertaken proactively.

Determining the optimal sequence of reperfusion versus stabilization of the limb may be difficult because the following two competing imperatives have to be reconciled: the period of warm ischemia must be as limited as possible (and should never extend beyond 6 hours from time of injury), yet skeletal stability must be achieved in a timely fashion without compromising any vascular repair. Deciding on the best sequence has attracted much debate over the past 4 decades. A meta-analysis of the data concluded that amputation rates are not affected by the sequencing of revascularization, whether undertaken before or after fracture stabilization. The authors acknowledged the retrospective nature of the cohort studies analyzed, and outcomes other than amputation were not considered in their review.

McHenry in 2002 retrospectively studied a cohort of 27 limbs with orthovascular injury secondary to gunshot wounds and concluded that revascularization (whether definitive or via a shunt) should be carried out before skeletal stabilization, on the basis of a nonsignificant trend toward higher fasciotomy rates in 5 cases where stabilization was prioritized. The cohort included brachial, femoral, and popliteal injuries; but the authors did not include patients with crural vessel injury. Furthermore, 13 of the 14 internal fixations were carried out in the group that had initial revascularization, suggesting possible selection bias. Initial revascularization followed by skeletal fixation was not associated with damage of the vascular repair, contradicting an often-quoted rationale that orthopedic manipulation and fracture fixation in the setting of a freshly repaired vessel carries a major risk of disruption.

The debate around sequencing has been blunted by the development of temporary vascular shunting as a means of ensuring early restoration of flow and facilitation of a window of opportunity for orthopedic intervention. Extensive experience with the use of vascular shunts during the wars in Afghanistan and Iraq includes clinical data suggesting that this damage control adjunct extends the window of limb salvage in the most severely injured extremities. Translational large animal data, also stemming from investigation during the wars, has shown improved extremity neuromuscular recovery and function with shorter ischemic times (less than 3 hours). Whichever strategy is chosen, it is worth reiterating that these injuries are infrequently seen and often require individualized solutions. Some cases merit early stabilization, others shunting, and some early definitive vascular repair.

Major Limb Amputation for Trauma

Amputations undertaken for the acutely injured and unsalvageable extremity offer a set of challenges that differ from those regularly encountered by vascular surgeons managing patients with unreconstructible peripheral vascular disease. In particular, patients with limbs that have been rendered unsalvageable by blast have very specific requirements. In such circumstances, guidelines developed by UK Defence Medical Services may prove helpful (and are applicable to the patient with non–blast-mangled extremity) as set out in Box 22-1 .

In assessing the viability of the distal soft-tissue envelope (which will define the level of amputation), medial and lateral longitudinal incisions should be used to extend the wounds in order to allow adequate exposure if the preexisting wounds do not afford this assessment. At initial débridement, all viable tissue should be preserved even if bone length appears excessive or if excess soft tissue is present. This is to avoid compromising definitive closure, particularly if further skin or soft-tissue necrosis occurs. Definitive flaps should not be performed at the initial débridement. This may result in the excision of viable tissue, which could be required for definitive wound closure, particularly if further excision is required or if nonstandard flaps are necessary. Definitive flaps are created at the time of wound closure, usually 2 to 5 days later.

Essentially a trauma amputation should be considered an extension of débridement, rather than a definitive procedure in its own right. By adopting this attitude, the limb is removed as part of the débridement of nonviable tissue, the tissues are excised at the most distal point possible, and the temptation to fashion formal flaps is avoided.

Assessment of the Injured Extremity

The patient with a severely injured or mangled extremity should be managed within trauma protocols based around Advanced Trauma Life Support guidelines or their equivalent. The limb injury, no matter how severe, should not detract from or delay any lifesaving interventions that need to be undertaken to ensure that major hemorrhage is controlled and that the airway is secured. Bleeding from the limb should be controlled; direct pressure applied through sterile dressings, combined with elevation, is appropriate. If unsuccessful, the application of a tourniquet is indicated. Ideally this should be a pneumatic tourniquet but a military-style combat application mechanical tourniquet with a windlass mechanism will suffice.

Each tissue type, skin, muscle, and nerve should be considered and assessed separately. The zone of injury (i.e., the part of the limb that has received the energy transference from the wounding mechanism) should be determined. This zone can vary in size depending on how the injury was induced; but, irrespective of size, all tissues within the injury zone will have been affected to a lesser or greater extent. Certain tissues, such as skin, are more robust and can tolerate a degree of injury, whereas others (fat, muscle) are more likely to suffer irreparable damage.

For extremities, it is important to determine whether a degloving component is present. This is when the skin has been sheared off the deep fascia, leading to thrombosis or avulsion of the skin perforating vessels and subsequent skin death. Degloving occurs in traction or shearing injuries and is often observed if a limb has been run over by a vehicle. Degloving also occurs in blast injuries, where the blast mechanism strips the skin away from the underlying tissues. Detecting the presence of a degloving injury can be difficult; but it should always be considered given a suspicious mechanism of injury. Soft-tissue appraisal should occur in conjunction with the orthopedic assessment. This should include an assessment of limb-length discrepancy, abnormal bony contour, joint function, and axial stability according to the usual “look/feel/move” paradigm.

A full neurovascular examination should be performed, although a depressed level of consciousness will not permit a full assessment of motor and sensory functions. The peripheral nerves of the extremity should be examined ( Table 22-2 ). In the foot, these are saphenous nerve (instep) medial and lateral plantar nerves (sole), sural nerve (outer border), superficial peroneal nerve (dorsum), and deep peroneal nerve (first web-space dorsum). In the hand, these are the median nerve (index finger), the ulnar nerve (little finger), and the superficial branch of the radial nerve (first web space).

Table 22-2

Functional Motor and Sensory Assessment of the Extremities

Nerves	Motor	Sensory	Significance
Upper Limb
Musculocutaneous nerve	Elbow flexion	Radial border of forearm	Injury in axilla/upper arm; risk of axillary/brachial artery injury
Median nerve	Wrist flexion, abduction of thumb. (Thumb can be brought out at 90° from palm.)	Thumb	Consider flexor compartment syndrome.
Ulnar nerve	Abduction of fingers	Little finger	May also have ulnar artery injury
Radial nerve	Extension of elbow, wrist, and fingers at metacarpophalangeal joints	First web	Consider extensor compartment syndrome.
Lower Limb
Saphenous nerve (terminal branch of femoral nerve)		Medial border of foot	Thigh injury or anterior thigh compartment syndrome. Femoral artery/vein may be injured.
Tibial nerve (sensory medial and lateral plantar nerves)	Plantarflexion of the foot	Sole of foot	Posterior compartment of leg injury or compartment syndrome. Posterior tibial artery may also be injured.
Sural nerve (branch of common peroneal nerve)		Lateral border of foot	Popliteal fossa injury
Common peroneal nerve	Ankle eversion (lateral compartment)		Indicates injury before division into deep and superficial branches (sensory loss in both superficial and deep branches). Lateral compartment injury or compartment syndrome
Superficial branch peroneal nerve		Dorsum of foot	Lateral compartment injury or compartment syndrome
Deep branch peroneal nerve	Dorsiflexion of the foot	First web space	Anterior compartment injury or compartment syndrome. Anterior tibial artery may also be injured.

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