Open Fractures. Gunshot Fractures. Crush Syndrome. Amputations.

Introduction

Open fractures, gunshot injuries, crushing injuries, and the management of severely mangled limbs constitute the most demanding fracture-related conditions encountered in orthopedic practice. The principles of management have evolved through extensive military and civilian trauma experience and emphasize early systematic care that addresses both the bone injury and the often more consequential soft-tissue and systemic components. This chapter synthesizes content from AO Principles of Fracture Management, Rockwood and Green’s, Apley & Solomon’s, and Miller’s Review.

Open Fractures

Definition and Epidemiology An open fracture is one in which the fracture site communicates with the external environment through a break in the skin and soft tissues. The terminology “compound fracture” is largely historical and has been replaced by “open fracture.” The principal complications of open fractures arise from the contamination of the wound and the underlying tissues — infection (acute and chronic osteomyelitis), delayed healing, non- union, and limb loss. Open fractures range in severity from a tiny puncture wound communicating with an underlying simple transverse fracture to a massive contaminated wound with extensive soft-tissue loss, bone loss, and vascular injury. The principal classifications and management principles reflect this enormous range of severity. Gustilo-Anderson Classification The Gustilo-Anderson classification, originally described in 1976 and refined in 1984, is the universal standard for open fracture classification: Type I: Wound less than 1 cm, clean, simple fracture pattern, minimal soft-tissue damage. Infection rate approximately 0-2%. Type II: Wound 1-10 cm, moderate soft-tissue damage, no extensive contamination, no flaps or avulsions. Infection rate approximately 2-7%. Type III: Wound greater than 10 cm OR extensive soft-tissue damage OR high-energy mechanism OR significant contamination OR specific injury patterns (gunshot, farm injury, segmental fracture) regardless of wound size. Infection rate approximately 7-25%. The Type III injuries are further subdivided: Type IIIA: Adequate soft-tissue coverage of the fracture despite extensive damage. Bone is covered without need for free flap or rotational flap.

Type IIIB: Extensive soft-tissue damage requiring free flap or rotational flap reconstruction. Bone is exposed and requires soft-tissue coverage. Type IIIC: Vascular injury requiring repair, regardless of other features. The injuries with vascular involvement have the highest amputation rates. The classification is most reliable when applied after surgical exploration, since the apparent wound on initial assessment can substantially underestimate the actual injury. The “small wound, large injury” of a high-energy gunshot or crush injury can produce dramatically more soft-tissue damage than the skin wound suggests. Initial Management

The initial management of any open fracture follows a sequence: ATLS resuscitation: Initial assessment and resuscitation according to ATLS principles, since most open fractures occur in the context of significant trauma. Assessment of the open fracture: The wound is gently examined, foreign material visible at the surface is removed, and the limb is assessed for neurovascular function distally. Repeated probing or examination is avoided to prevent additional contamination. Provisional management: Sterile saline-soaked gauze is placed over the wound. Photography of the wound may be useful for documentation and for surgical planning. Provisional splinting of the fracture provides comfort and prevents further injury. Antibiotic administration: As early as possible, ideally within 1 hour of presentation. The earliest possible administration is the single most important factor for reducing infection rates. The standard regimens vary by Gustilo grade: • Type I: First-generation cephalosporin (cefazolin) for 24 hours. • Type II: First-generation cephalosporin for 24 hours, with extension or addition of aminoglycoside in some protocols. • Type III: First-generation cephalosporin plus aminoglycoside (or extended-spectrum cephalosporin) for 72 hours, with consideration of penicillin for anaerobic coverage in farm injuries or grossly contaminated wounds. The trend in modern practice has been toward shorter antibiotic courses (24 hours rather than 72 hours for most Type III fractures), with the emphasis on appropriate surgical debridement rather than prolonged antibiotic prophylaxis. Tetanus prophylaxis: Tetanus toxoid booster for any patient with incomplete prior immunization or with a contaminated wound and uncertain immunization status. Tetanus immunoglobulin for patients who have never been immunized. Definitive surgical management: Early surgical debridement and stabilization. Surgical Management The principles of surgical management of open fractures include:

Timing: Historically the “6-hour rule” suggested debridement within 6 hours of injury. Modern evidence supports the principle of early debridement but suggests that the absolute timing is less critical than the immediate administration of antibiotics. Most centers aim for debridement within 12-24 hours of injury, with grossly contaminated or vascular-injury cases being treated more urgently. Debridement: Thorough surgical debridement is the cornerstone of management. The principles include: extension of the traumatic wound as needed for adequate exposure; identification and excision of all devitalized tissue including skin edges, fat, fascia, muscle, and bone; preservation of all viable tissue; identification and protection of major neurovascular structures; copious irrigation with sterile saline (with the volume traditionally cited as 3 L for Type I, 6 L for Type II, 9 L for Type III, though more recent evidence has questioned the importance of large irrigation volumes); and assessment of muscle viability (the “4 Cs” — color, consistency, contractility, capacity to bleed). The FLOW trial (Fluid Lavage of Open Wounds, 2015) demonstrated that low-pressure pulsatile lavage was non-inferior to high-pressure lavage, and that saline irrigation was superior to soap solution; current practice favors gentle low-pressure saline irrigation. Fracture stabilization: The choice of stabilization depends on the fracture pattern, the soft-tissue injury, and the contamination level. Type I and many Type II fractures can be managed by internal fixation (intramedullary nailing, plate fixation) at the time of debridement. Type III fractures often require external fixation initially with conversion to internal fixation after wound healing and resolution of soft-tissue injury (the “fix and flap” approach for Type IIIB). Wound management: The traditional approach left the wound open for delayed primary closure or healing by secondary intention; modern approaches increasingly favor primary closure when feasible, with use of negative-pressure wound therapy (vacuum-assisted closure, VAC) for wounds that cannot be primarily closed. Vacuum-assisted closure has been shown to facilitate wound contraction, reduce infection rates, and prepare wounds for definitive closure. Soft-tissue coverage: Type IIIB fractures require coverage by rotational or free flap. The principle of “fix and flap” — definitive bone fixation and soft-tissue coverage in a single combined orthopedic-plastic surgical procedure within 5-7 days of injury — produces better outcomes than serial operations. The choice of flap depends on the location, the size of the defect, and the available donor sites. Long-Term Issues The principal long-term concerns after open fracture include: infection (acute, chronic, with biofilm-associated implant infection being particularly difficult to manage); non-union (substantially elevated rates compared with closed fractures); soft-tissue compromise; and limb-length discrepancy from bone loss.

Gunshot Fractures

Classification by Energy Gunshot injuries are classified by the energy of the projectile: Low-velocity (typically <600 m/s): Most handgun bullets and BB gun pellets. The injury is principally to the immediate path of the bullet, with limited cavitation. Soft-tissue damage is correspondingly limited. High-velocity (typically >600 m/s): Military rifles and certain hunting rifles. The high- energy projectile produces extensive cavitation with shock-wave damage to tissues at considerable distance from the apparent wound track. Soft-tissue damage is dramatic. Close-range shotgun injuries: The high-energy delivery from a shotgun at close range produces a wide zone of devastating injury, often with substantial soft-tissue loss. The clinical distinction is important: low-velocity wounds can often be treated as Gustilo Type I or II open fractures with local wound care and antibiotic prophylaxis; high-velocity wounds and close-range shotgun wounds are Gustilo Type III injuries requiring formal debridement. Management Principles Low-velocity gunshot fractures are managed as: local wound care (irrigation, debridement of necrotic tissue at the wound margins, retention or removal of the bullet according to clinical considerations); intravenous antibiotics (cefazolin for 24-48 hours in most protocols); tetanus prophylaxis; fracture management appropriate to the fracture pattern. The bullet itself is generally left in place unless it is in a problematic location (intra- articular, in a major nerve or vessel, in subcutaneous tissue producing symptoms). High-velocity and close-range gunshot fractures are managed as Gustilo Type III injuries with formal debridement, longer courses of broad-spectrum antibiotics, and external fixation in many cases. The classical orthopedic implication is that low-velocity gunshot fractures should not be assumed to be “minor” wounds — careful assessment and standard open fracture management is required.

Crush Syndrome

Crush syndrome is the systemic syndrome that follows release of a crushed limb from prolonged compression. The condition was first described in the London Blitz of 1941 and has been encountered in earthquakes, mining accidents, motor vehicle accidents with prolonged extrication, building collapses, and other disasters. Pathophysiology The pathophysiology involves the systemic effects of muscle ischemia and reperfusion injury. During the period of compression, the affected muscle is rendered ischemic, with

progressive accumulation of intracellular contents and inflammatory mediators. Upon release of the compression, the affected tissue is reperfused, and the massive release of these contents into the circulation produces the systemic syndrome. The principal systemic consequences include: Hyperkalemia: Released from damaged muscle cells; can produce cardiac arrhythmia and arrest, particularly with reperfusion. Myoglobinuria and acute kidney injury: Myoglobin released from damaged muscle precipitates in the renal tubules, producing acute tubular necrosis. The classical “tea- colored urine” indicates myoglobinuria. Metabolic acidosis: From anaerobic metabolism and release of intracellular acids. Hypocalcemia: From precipitation in damaged muscle and other mechanisms. Compartment syndrome: Of the affected limb, requiring fasciotomy. DIC and other systemic complications: From the massive inflammatory release. Management The management combines: Pre-extrication preparation: When possible, intravenous fluid resuscitation should begin before release of the compression. Bicarbonate may be added to the fluids to alkalinize the urine and reduce myoglobin precipitation. Aggressive fluid resuscitation: Large-volume crystalloid (often 10-20 L over the first 24- 48 hours), targeting urine output of 200-300 mL/h to flush myoglobin through the renal tubules. Management of hyperkalemia: Calcium gluconate to stabilize the cardiac membrane, insulin-glucose to shift potassium intracellularly, beta-2 agonists, sodium bicarbonate, and renal replacement therapy as needed. Renal replacement therapy: For oliguric or anuric renal failure, often required in severe cases. Surgical management of the limb: Fasciotomy if compartment syndrome develops or is anticipated. The decision regarding limb salvage versus amputation depends on the viability of the limb and the patient’s systemic condition; in some cases primary amputation is required to control the systemic consequences.

Amputations

Amputation is the surgical removal of a limb or limb segment. It is among the most consequential decisions in orthopedic surgery, with profound implications for the patient’s future life.

Indications The principal indications for amputation include: Vascular injury without reconstruction option: Severe vascular injury with prolonged ischemia or with inability to reconstruct the vascular supply. Massive trauma: Where the limb cannot be salvaged or where salvage would produce a worse outcome than amputation. The MESS (Mangled Extremity Severity Score) and similar tools assess the predictability of salvage versus amputation. Infection: Severe established osteomyelitis with limb destruction; gas gangrene; necrotizing fasciitis with extensive limb involvement. Malignant tumors: Bone and soft-tissue sarcomas where wide local excision is not feasible. Severe deformity or non-functional limb: Where amputation would provide better function than retention. Vascular disease: Critical limb ischemia from peripheral arterial disease, diabetic foot disease, and other vascular conditions; this is among the commonest indications for amputation overall in modern practice. Patient request: In selected situations. Mangled Extremity Severity Score (MESS) The MESS scores four factors: Skeletal/soft-tissue injury: 1 point for low-energy injury, 2 for medium-energy, 3 for high-energy, 4 for very high-energy/crush. Limb ischemia: 1 point for reduced pulse with normal perfusion, 2 for absent pulse with reduced perfusion, 3 for cool/pale/paralyzed limb. Doubled if ischemia >6 hours. Shock: 0 points for normotensive, 1 for transient hypotension, 2 for persistent hypotension. Age: 0 points for <30 years, 1 for 30-50 years, 2 for >50 years. A score ≥7 has historically been considered predictive of amputation; however, the MESS has limitations, and modern practice emphasizes individualized assessment rather than rigid score-based decisions. Amputation Levels The principal amputation levels in the lower extremity include: Foot: Toe amputations, ray resections (involving the metatarsal), transmetatarsal amputation, Lisfranc amputation (through the tarsometatarsal joints), Chopart amputation (through the midtarsal joints — preserves heel pad with associated equinus tendency),

Boyd amputation (calcaneotibial fusion preserving heel pad), Symes amputation (disarticulation at the ankle preserving the heel pad). Below-knee (transtibial): The standard amputation for severe foot or distal leg pathology with viable proximal tissue. Preserves the knee joint and provides excellent prosthetic function. The recommended stump length is 10-15 cm below the knee joint. Through-knee (knee disarticulation): Preserves the femoral length and provides an end- bearing stump. Less commonly used than transtibial or above-knee amputation. Above-knee (transfemoral): Performed when below-knee amputation is not feasible. Preserves the hip joint. Functional outcomes are less good than transtibial because of the loss of the knee joint. Hip disarticulation and hemipelvectomy: Rarely required, reserved for proximal limb tumors or extensive infection. In the upper extremity, amputation levels include digital and ray amputations, partial hand amputation, wrist disarticulation, below-elbow (transradial) amputation, elbow disarticulation, above-elbow (transhumeral) amputation, shoulder disarticulation, and forequarter amputation. Principles of Amputation Surgery The principles include: preservation of length where possible (each additional inch of preserved stump provides better functional outcomes); appropriate soft-tissue coverage of the stump (with attention to providing a well-vascularized, well-padded stump that can tolerate prosthetic loading); careful management of nerves (transection at appropriate length with avoidance of stump neuromas); careful management of vessels (ligation rather than transfixion to prevent late complications); appropriate bone shaping to prevent prominent bone edges; appropriate soft-tissue suturing and skin closure to provide a durable scar; and postoperative rehabilitation including prosthetic fitting at appropriate timing. Outcomes and Prosthetics The outcomes of amputation depend on the level (more proximal amputations producing worse functional outcomes), the indication (traumatic amputations in healthy patients producing better outcomes than vascular amputations in older patients with multiple comorbidities), the quality of the stump, and the prosthetic fitting and rehabilitation. Modern prosthetic technology, including microprocessor-controlled knees and feet, has substantially improved functional outcomes. Targeted muscle reinnervation (TMR) and other advanced techniques provide intuitive control of myoelectric upper limb prostheses for selected patients. Phantom Limb Pain Phantom limb pain — pain felt in the missing limb — affects approximately 50-80% of amputees. The condition is poorly understood and often difficult to treat. Multiple

pharmacological agents (gabapentin, pregabalin, tricyclic antidepressants, opioids), interventional procedures (peripheral nerve blocks, stump revision for symptomatic neuromas, targeted muscle reinnervation, peripheral nerve interface electrodes), and other therapies are used with variable success.

Summary and Take-Home Points

Open fractures require prompt antibiotic administration (the single most important intervention), tetanus prophylaxis, early surgical debridement, fracture stabilization (often by external fixation initially with conversion to internal fixation), and appropriate wound management (with primary closure when feasible, vacuum-assisted closure when not, and free or rotational flap coverage for Gustilo Type IIIB fractures). The Gustilo-Anderson classification provides the principal framework for management. Gunshot fractures are classified by velocity; low-velocity wounds are managed as Gustilo Type I or II, while high- velocity and close-range wounds require formal management as Type III injuries. Crush syndrome is the systemic consequence of release from prolonged compression, with hyperkalemia, myoglobinuria-induced acute kidney injury, and metabolic acidosis as principal features, requiring aggressive fluid resuscitation, management of hyperkalemia, and renal replacement therapy as needed. Amputation, while a last resort in many situations, is the appropriate management for unsalvageable limbs and may provide better functional outcomes than salvage in selected cases; the MESS provides a framework for the decision, modern surgical techniques and prosthetic technology have improved outcomes substantially, and phantom limb pain remains a significant long-term concern.