Management of lower extremity trauma

Introduction

Injury is the leading cause of death and disability in all age groups, causing approximately 5 million deaths worldwide annually, accounting for 9% of all deaths. In the United States, unintentional injuries or accidents are the third leading cause of death in all age groups, accounting for 6% of all deaths in 2018. Indeed, unintentional injuries are the leading cause of death in the population aged 1–44 years. The relative burden of mortality from injury is far more significant at younger ages, accounting for 31.8% of all deaths for the 1–9 year age group, 38.3% in the 10–24 year age group, and 34.0% in the 25–44 year age group. In developing countries, injury-related mortality rates are even higher than those in developed countries.

Trauma to the lower extremities is a common injury pattern observed in emergency medical and surgical practice. The management of lower extremity injuries involves a multidisciplinary approach. Initial assessment begins with the primary investigation of life-threatening injuries based on the Advanced Trauma Life Support (ATLS) protocol, which is a standardized acute care system that aims to reduce trauma mortality during the golden hour.

Following the initial evaluation of the medical condition and spinal cord injury, a thorough investigation of the extremity injury is initiated by the trauma team, which includes general surgery, vascular surgery, orthopedic surgery, and plastic surgery specialists. This integrated access to the patients, also known as Levin’s concept of orthopedic approach, should be applied from the emergency room to prevent amputation, restore limb function, and improve the quality of life outcome in patients with lower extremity injury. With a multidisciplinary team approach, surgical debridement of the necrotic tissue and external fixation of the fractured bone is followed by immediate flap coverage or delayed flap surgery after wound care. In cases of bone loss, bone graft or vascularized bone graft can be performed as a delayed procedure or by immediate bone flap coverage simultaneously with soft-tissue coverage ( Algorithm 2.1 ).

Algorithm 2.1

Simple workflow for the management of lower extremity trauma.

Basic science

Inflammatory response to injury

Without medical treatment, most patients with major trauma die due to blood loss. This first began to change in the 16th century when the French surgeon Ambroise Paré was the first to ligate arteries during amputation. Treatment improved over the following centuries, especially after the outbreak of World War II. Most patients who would have died in earlier times are now being saved thanks to advances in bleeding control. However, more than 6% of survivors of massive hemorrhage develop septic complications, with 20% of patients developing multi-organ failure (MOF). The activation of the immune system following trauma is vital for the protection and healing of the wound. Following severe trauma, the human body responds similarly to systemic inflammatory response syndrome (SIRS) and sepsis, and bacterial pathogens and injury cause similar immunologic responses at the genomic and transcriptomic levels. This similarity previously led to the assumption that post-traumatic SIRS was a response to bacterial inoculation. However, it is now considered to be a sterile process. This response is a combination of proinflammatory and anti-inflammatory responses, which start within 30 min of a major injury to favor blood loss and tissue damage rather than infection.

SIRS results from the release of damage-associated molecular patterns or alarmins after tissue injury. Recognition of these patterns leads to the activation of immune cells, such as neutrophils and monocytes, and the rapid generation of C3, C5a, and interleukins, which activate the inflammatory process and can cause early MOF ( Fig. 2.1A ). The post-traumatic immune system has a balancing compensatory anti-inflammatory response to dampen the inflammatory reaction, termed compensatory anti-inflammatory response syndrome (CARS), which can be described as postinflammatory immunosuppressive status. This feedback loop is characterized by increased levels of anti-inflammatory cytokines and cytokine antagonists. The anti-inflammatory response limits progressive tissue damage and maintains homeostasis to prevent further organ damage. In the balancing process of proinflammatory and anti-inflammatory reactions, the response can either be stabilized at baseline or progress to persistent inflammation, immunosuppression, and catabolism syndrome (PICS), with an increased risk of MOF and sepsis during the critical care period ( Fig. 2.1B ). Plastic surgeons should evaluate the general condition and immune response of the patient and accordingly decide when to reconstruct the defect of the limb or other parts of the body, not only for successful reconstructive surgery limb salvage but also to save the patient.

Diagnosis and patient presentation