Overview of Bone Fractures

Overview

Definition

A fracture is a disruption in the cortex of a bone. 

Epidemiology

• Around 50 million/year in the United States
• Closely associated with the prevalence and incidence of:
  • Automobile accidents
  • Occupational injuries
  • Trauma
• Increased in patients with comorbid conditions that predispose them to falls:
  • Epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy
  • Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope
  • Osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis
• Men affected more often than women

Classification

Risk factors

• Smoking
• Osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis
• Diabetes
• Immunosuppression with steroids
• Age

Pathophysiology

The general principle behind all fractures is that the bone is subjected to a load that overcomes the bone’s bearing capacity, leading to loss of structural integrity. 

• Traumatic mechanisms of fracture:
  • Blunt: direct transference of energy by a blunt object
  • Penetrating: direct discontinuity of tissues by sharp objects or gunshot
  • Blast: transference of kinetic energy by the blast wave that results from explosive devices
• Primary fracture healing: achieved with the proper anatomic reduction of the fractured segments 
  • Hematoma formation: 1st 5 days 
  • Fibrocartilaginous callus formation: days 5–11
  • Bony callus formation: days 11–18
  • Bone remodeling Bone remodeling Bone, while seemingly inert, is an active, growing, and changing part of the human body, in addition to being the body's primary calcium reservoir. In the correct homeostatic conditions, bone can remodel in response to damage, stress, or hormonal signaling (parathyroid hormone and calcitonin). Bone Remodeling and Healing: from day 18 and continuing for many months
• Secondary healing occurs when anatomic reduction or compression is not feasible: 
  • Fracture phase
  • Soft callus formation
  • Hard callus formation
  • Remodeling phase

Clinical Presentation

A thorough history with recent injury or fall details, risk factors for fracture, medications, and past history of a previous fracture are all important.

History

• Fall: How did it occur?
• Recent trauma: 
  • Automobile accident
  • Injury
  • Struck with an object
• Sudden onset of pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain 
• Inability to move the affected body part
• Patients with osteoporosis may experience no- or low-impact trauma.
• Less acute causes of fractures:
  • Stress fractures can occur with repeated impact, such as with running:
    • Can be missed on an X-ray
    • More easily diagnosed on an MRI or a bone scan
  • Avascular necrosis can cause fracture of the scaphoid bone in the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand or the femoral head in the hip.

Physical examination

• Deformity of the affected location (e.g., hip fracture)
• Pain exacerbated on palpation and percussion
• Edema and inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body's defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation
• Crepitus on palpation 
• Immobility due to pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain
• Joint instability
• Inability to bear weight due to pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain 
• Signs of compartment syndrome Compartment Syndrome Compartment syndrome is a surgical emergency usually occurring secondary to trauma. The condition is marked by increased pressure within a compartment that compromises the circulation and function of the tissues within that space. Compartment Syndrome if such is being developed:
  • Coldness of the distal extremity
  • Paresthesias or paresis
  • Reduced sensitivity
  • Absent pulses
  • Volkmann contracture (prolonged ischemia)
• Other signs in the context of a patient with trauma:
  • Hematomas/ecchymosis
  • Excoriations/lacerations

Diagnosis

The diagnosis of a possible fracture is made clinically initially and confirmed on diagnostic imaging.

Imaging

• X-ray findings: fracture lines/discontinuity of anatomy
  • Linear lucency
  • Sharp angles
  • No surrounding cortex at the fracture site
  • Irregular margins
  • False positive readings:
    • Can be due to nutrient vessels that appear as linear lucencies
    • Nutrient canals are smooth and have a sclerotic margin.
    • Accessory ossicles: bone fragments that form a secondary ossification center and are not due to a fracture
    • Sesamoid bones: extra “bone islands” that form in a tendon
• Ultrasonography:
  • High sensitivity and specificity
  • Used in emergency departments and sports facilities 
  • No ionizing radiation
• CT scan and MRI:
  • Beneficial for stress fractures or spinal fractures
  • Provide good visualization of the fracture site and possible displacement

Descriptions of fractures on imaging

• Location
• Displaced or nondisplaced
• Extent:
  • Complete: extends through the entire cortex
    • More common in adults
    • Transverse: perpendicular to the long axis of the bone
    • Oblique: diagonal to the long access of the bone.
    • Spiral: caused by a twisting force
  • Incomplete: extends through only part of the cortex 
    • Most commonly seen in children
    • Greenstick fracture Greenstick fracture The bones of growing children exhibit unique characteristics, which, combined with the unique mechanisms of injury seen in children, result in fracture patterns differing significantly from those common in adults. The greenstick fracture is an incomplete fracture usually seen in long bones. Greenstick Fracture
    • Buckle fracture
• Comminuted: produces > 2 fragments
  • Segmental: Central portion of the bone shaft becomes an isolated segment.
  • Butterfly: Central portion has a triangular shape.
• Simple: produces only 2 fragments
• Intraarticular (crosses a joint surface) or extraarticular (does not cross)
• Integrity of limb compartments:
  • Closed: Fractured ends remain within their original compartment.
  • Open fractures:
    • 1 or both fractured ends pierce through the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the Skin and end up exposed.
    • May be difficult to see
    • May have active bleeding
• Displacement: describes the amount by which the distal segment is offset from the proximal segment
  • Angulation: the degree to which the distal segment is angulated from its original position
  • Override: the amount by which the proximal and distal fragments overlap each other
• Impaction: the amount by which the distal fragment has impacted into the proximal fragment
• Distraction: how far apart the proximal and distal fragments are (the opposite of overlap)
• Avulsion fracture: a bone fragment that is “pulled off” by a ligament or a tendon

Secondary findings

• Increased opacity of soft tissues (acute inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body's defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation and edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema)
• Joint effusion
• Periosteal reaction/callus formation

Gustilo and Anderson classification of open fractures

• Grade 1: clean wound < 1 cm in length, simple fracture
• Grade 2: open wound 1–10 cm, no flaps or extensive tissue damage
• Grade 3: open segmental fracture with extensive soft tissue injuries, also includes wounds more > 8 hours old
• Grade 3a: adequate soft tissue covering of the fracture despite extensive soft tissue damage
• Grade 3b: inadequate soft tissue covering; periosteal stripping
• Grade 3c: open fracture with a vascular injury that requires surgery for viability of the limb

Management

The goal of fracture management by reducing it and allowing the normal healing process to take place is to restore the anatomy, reduce pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain, and allow the patient to return to the previous level of functioning.

Manipulative reduction and immobilization (splints)

• Fractured ends are manipulated back into position and immobilized using a splint or a cast. 
• Successful reduction should be achieved within a few hours after the injury.
• Reduction is either the definitive management or temporary until surgery can be performed.
• An X-ray must be obtained after immobilization to ensure adequate reduction.

Open fractures

Open fractures require prompt management in the emergency department and transfer to the operating room (OR) for definitive management and hospitalization.

• “Rule of 3” irrigation with normal saline (according to Gustilo and Anderson):
  • Grade 1: 3 L
  • Grade 2: 6 L
  • Grade 3: 9 L
  • Continues in the OR
• Debridement and removal of contaminating debris
• Tetanus Tetanus Tetanus is a bacterial infection caused by Clostridium tetani, a gram-positive obligate anaerobic bacterium commonly found in soil that enters the body through a contaminated wound. C. tetani produces a neurotoxin that blocks the release of inhibitory neurotransmitters and causes prolonged tonic muscle contractions. Tetanus prophylaxis if: 
  • Patient has not completed the tetanus toxoid immunization series
  • No booster in the past 5 years
  • If there is a high likelihood of Clostridium tetani contamination → tetanus toxoid + human tetanus immunoglobulin (HTIG)
• Antibiotics
• Sterile dressing
• Immobilization
• Analgesia as needed

Complications

• Neurovascular injury: Chronic numbness or paresthesia may result in the area of a fracture depending on the extent of injury to the nerves in that area.
• Deep vein thrombosis Deep vein thrombosis Deep vein thrombosis (DVT) usually occurs in the deep veins of the lower extremities. The affected veins include the femoral, popliteal, iliofemoral, and pelvic veins. Proximal DVT is more likely to cause a pulmonary embolism (PE) and is generally considered more serious. Deep Vein Thrombosis ( DVT DVT Deep vein thrombosis (DVT) usually occurs in the deep veins of the lower extremities. The affected veins include the femoral, popliteal, iliofemoral, and pelvic veins. Proximal DVT is more likely to cause a pulmonary embolism (PE) and is generally considered more serious. Deep Vein Thrombosis): 
  • Blood clots can form in the arm Arm The arm, or "upper arm" in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm or leg Leg The lower leg, or just "leg" in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins after a period of immobility and decreased activity.  
  • Anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants are indicated if the patient is at high risk for DVT DVT Deep vein thrombosis (DVT) usually occurs in the deep veins of the lower extremities. The affected veins include the femoral, popliteal, iliofemoral, and pelvic veins. Proximal DVT is more likely to cause a pulmonary embolism (PE) and is generally considered more serious. Deep Vein Thrombosis.
• Fat embolism: 
  • Can occur from fat in the bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow traveling through a blood vessel after a fracture
  • Similar consequences as with a thrombotic embolism
• Compartment syndrome:
  • A surgical emergency
  • Usually secondary to trauma
  • Marked by increased pressure within a compartment that compromises the circulation
  • Long-bone fractures are the most common cause, with the leg Leg The lower leg, or just "leg" in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg and forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term "forearm" is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm compartments frequently affected.
• Osteomyelitis Osteomyelitis Osteomyelitis is an infection of the bone that results from the spread of microorganisms from the blood (hematogenous), nearby infected tissue, or open wounds (non-hematogenous). Infections are most commonly caused by Staphylococcus aureus. Osteomyelitis: bone infection
  • Results from the spread of microorganisms from wounds associated with an open fracture
  • Most commonly caused by Staphylococcus Staphylococcus Staphylococcus is a medically important genera of Gram-positive, aerobic cocci. These bacteria form clusters resembling grapes on culture plates. Staphylococci are ubiquitous for humans, and many strains compose the normal skin flora. Staphylococcus aureus
• Nonunion of the proximal and distal ends: failure to heal properly
• Premature osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis:
  • Due to cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage destruction and changes of the subchondral bone
  • Increased risk with:
    • Older age
    • Obesity
    • Repetitive joint use
    • Trauma
• Complex regional pain syndrome Complex Regional Pain Syndrome Complex regional pain syndrome (CRPS) is a chronic regional neuropathic pain condition characterized by excruciating pain (out of proportion to apparent tissue damage or inciting trauma), paresthesia, allodynia, temperature abnormalities, skin discoloration, edema, reduced range of motion, and bone demineralization. Complex Regional Pain Syndrome (CRPS):
  • A condition characterized by chronic pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain, often of the distal limbs
  • Can occur after a fracture or surgery and is difficult to manage

Differential Diagnosis

• Sprains: traumatic elongation of the ligaments of a joint, causing inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body's defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation, ecchymosis, edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema, intense pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain, and inability to bear weight. Sprains account for 20% of sports-related injuries.
• Malignancy: fractures after a minor injury should raise suspicion of an underlying malignant process, such as metastatic prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. Prostate and other Male Reproductive Glands, lung, breast cancer Breast cancer Breast cancer is a disease characterized by malignant transformation of the epithelial cells of the breast. Breast cancer is the most common form of cancer and 2nd most common cause of cancer-related death among women. Breast Cancer, or multiple myeloma Multiple myeloma Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma. Diagnosis is made by imaging and possible biopsy, and management of the underlying pathology is indicated.
• Osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis: severe demineralization with low bone density can cause fractures with little stress on the bone, such as with coughing, bending, or minor injuries. Osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis most often presents clinically with frequent fractures and loss of vertebral height. Diagnosis is established by measuring bone mineral density. Management includes lifestyle modifications, maintaining adequate levels of calcium and vitamin D, and the use of bisphosphonates Bisphosphonates Bisphosphonates are pyrophosphate analogs most well-known for treating osteoporosis by preventing bone loss. Bisphosphonates end in the suffix "-dronate" or "-dronic acid" (e.g., alendronate, risedronate, pamidronate) and bind to hydroxyapatite crystals in bone, inhibiting osteoclast-induced bone resorption. Bisphosphonates.
• Rickets Rickets Rickets and osteomalacia are disorders of decreased bone mineralization. Rickets affects the cartilage of the epiphyseal growth plates in children. Although most cases of rickets are due to vitamin D deficiency, other genetic and nutritional disorders as well as medications can cause these disorders. Rickets commonly presents with skeletal deformities and growth abnormalities. Osteomalacia and Rickets and osteomalacia Osteomalacia Rickets and osteomalacia are disorders of decreased bone mineralization. Osteomalacia affects the sites of bone turnover in children and adults. Although most cases are due to vitamin D deficiency, other genetic and nutritional disorders as well as medications can cause these disorders. Osteomalacia can present with bone pain, difficulty with ambulation and pathologic fractures. Osteomalacia and Rickets: disorders of decreased bone mineralization. Rickets Rickets Rickets and osteomalacia are disorders of decreased bone mineralization. Rickets affects the cartilage of the epiphyseal growth plates in children. Although most cases of rickets are due to vitamin D deficiency, other genetic and nutritional disorders as well as medications can cause these disorders. Rickets commonly presents with skeletal deformities and growth abnormalities. Osteomalacia and Rickets can be due to severe vitamin D deficiency or genetic disorders. Rickets Rickets Rickets and osteomalacia are disorders of decreased bone mineralization. Rickets affects the cartilage of the epiphyseal growth plates in children. Although most cases of rickets are due to vitamin D deficiency, other genetic and nutritional disorders as well as medications can cause these disorders. Rickets commonly presents with skeletal deformities and growth abnormalities. Osteomalacia and Rickets commonly presents with skeletal deformities and growth abnormalities, while osteomalacia Osteomalacia Rickets and osteomalacia are disorders of decreased bone mineralization. Osteomalacia affects the sites of bone turnover in children and adults. Although most cases are due to vitamin D deficiency, other genetic and nutritional disorders as well as medications can cause these disorders. Osteomalacia can present with bone pain, difficulty with ambulation and pathologic fractures. Osteomalacia and Rickets can present with bone pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain, difficulty with ambulation, and pathologic fractures. Diagnosis is made on the basis of a combination of clinical findings, laboratory tests, and imaging. Treatment includes vitamin D, calcium, and phosphorus supplementation.