INTRODUCTION — Competent fracture care requires a basic knowledge of bone biology and healing, a systematic approach to fracture evaluation and description, and a practical understanding of basic splinting and casting techniques. The general principles of bone healing and proper fracture description will be reviewed here. Fractures that are complicated, high risk, or unresponsive to appropriate conservative management should be promptly referred to a physician with expertise in managing fractures.
For information on specific fractures, please see the relevant topic reviews. Stress fractures and pediatric fractures are reviewed separately. (See "Overview of stress fractures" and "General principles of fracture management: Fracture patterns and description in children".)
BIOLOGY OF BONE HEALING — Bone is a composite structure with mineral and organic components. The mineral component contains calcium, phosphate, and hydroxyl ions which are organized into a compound called hydroxyapatite (Ca5(PO4)3(OH)). This mineral skeleton provides the strength, stiffness, and rigidity characteristic of bone. The organic or protein component consists primarily of type I collagen, which lends tensile strength and resiliency. The outer covering of bone, the periosteum, provides the vascular supply that plays an essential role in fracture healing. The periosteum in children is substantially thicker and more robust than in adults, accounting in part for the more rapid healing of pediatric fractures [1,2]. (See "Normal skeletal development and regulation of bone formation and resorption".)
Bone healing is usually divided into three slightly overlapping stages: inflammatory, reparative, and remodeling [2-5]. It is difficult to provide an approximate time frame for each phase because healing rates vary widely according to age and comorbidities. As an example, a simple toe fracture in a healthy young child may heal completely in four weeks while the same fracture in a 65 year old smoker may not heal completely for several years.
The initial inflammatory phase is dominated by vascular events. Following a fracture, a hematoma forms which provides the building blocks for healing. Subsequently, reabsorption occurs of the 1 to 2 mm of bone at the fracture edges that have lost their blood supply. It is this bone reabsorption that makes fracture lines become radiographically distinct 5 to 10 days after injury. Next, multipotent cells are transformed into osteoprogenitor cells, which begin to form new bone.
In the reparative phase, new blood vessels develop from outside the bone that supplies nutrients to the cartilage, which begins to form across the fracture site. Nearly complete immobilization is desirable during both the inflammatory phase and the early reparative phase to allow for the growth of these new vessels. However, once neovascularization is complete, progressive loading and stress across the fracture site are desirable to augment callus formation.
Callus typically forms as a collar of new, endochondral bone around the fractured area. This callus is initially highly cartilaginous, but hardens as mineralization and endochondral calcification occur during the remodeling phase. Late in the reparative phase, clinical union of the fracture occurs. Clinical union occurs when the fractured bone does not shift on clinical examination, the fracture site is nontender, and the patient can use the injured limb without significant pain. Because the initial callus is cartilaginous, clinical union may occur before evidence of radiographic union is appreciable on radiographs. Clinical union classically marks the end of the reparative phase of fracture healing.
In the remodeling phase, the endochondral callus becomes completely ossified and the bone undergoes structural remodeling. The process of remodeling occurs quickly in young children, who remodel their entire skeleton every year. By late childhood, the rate of skeletal remodeling is approximately 10 percent per year and continues near this level throughout life .
In addition to patient age, other factors affecting the rate of bone remodeling include thyroid and growth hormone levels, calcitonin, glucocorticoids, and nutritional status [7,8]. Common conditions that impair fracture healing include diabetes mellitus, arteriovascular disease, anemia, hypothyroidism, malnutrition (eg, vitamin C or D deficiencies, inadequate protein intake), excessive chronic alcohol use, and tobacco use. Specific medications may also impair fracture healing, including glucocorticoids and certain antibiotics (eg, ciprofloxacin). The effect of nonsteroidal antiinflammatory drugs (NSAIDs) on fracture healing remains controversial. These issues are discussed in greater detail separately. (See "Bone disease with hyperthyroidism and thyroid hormone therapy" and "Bone disease in diabetes mellitus" and "Vitamin intake and disease prevention" and "Osteoporotic fracture risk assessment" and "Clinical features and evaluation of glucocorticoid-induced osteoporosis" and "Nonselective NSAIDs: Overview of adverse effects", section on 'Possible effect on fracture healing'.)
Overview — The essential first step of fracture treatment is to identify precisely the type of fracture present. At a minimum, a fracture should be identified using the following:
●Name of the injured bone
●Location of the injury (eg, dorsal or volar; metaphysis, diaphysis, or epiphysis)
●Orientation of the fracture (eg, transverse, oblique, spiral)
●Condition of the overlying tissues (eg, open or closed fracture).
Other important descriptors include fracture angulation, comminution, and displacement. Each aspect of fracture description is discussed below and diagrams depicting common fracture types are provided (figure 1 and figure 2).
Fractures are described based upon the radiographs obtained. A table describing the most common radiographic views according to injury location is provided (table 1). See the topic reviews dealing with specific fractures for additional information about the radiographs needed for these injuries.
Location: bone and aspect — Proper fracture description begins with precise identification of the injured bone. Lay terminology such as "finger" or "wrist" should be avoided; precise anatomic terms, such as "proximal phalanx" or "scaphoid" should be used.
Once the fractured bone is identified, the aspect of the injury is described using precise anatomic terms (figure 3). "Medial" and "lateral" are such common and precise descriptors. With hand and forearm fractures, the descriptors "radial" and "ulnar" are used instead of medial and lateral, and "dorsal" and "palmar" are used instead of anterior and posterior.
Long bone fractures should be described using the involved regions of the bone: metaphysis, diaphysis, or epiphysis (figure 1). Diaphyseal fractures are further characterized as involving the proximal, middle, or distal third of the bone, or the junction between two of these regions.
Fractures that extend into a joint space are referred to as "intra-articular." Intraarticular fractures are generally more serious injuries and commonly require surgery since optimal healing requires precise anatomic reduction. Intraarticular fractures are characterized by the percentage of the joint space they disrupt. As an example, a fracture of the distal interphalangeal joint where one third of the affected bone is displaced is described as involving 30 percent of the joint space.
Some fractures are associated with unique names that are more easily identifiable and descriptive than the traditional anatomic approach. For instance, a "supracondylar fracture" is more recognizable, descriptive, and concise than a "fracture of the distal humerus at the metaphyseal-diaphyseal junction." A table listing several of these common fractures is provided (table 2).
The Salter-Harris classification scheme is used to describe fractures involving the growth plate (figure 4). The risk of complications involving the growth plate increases in parallel with the Salter-Harris type (ie, type I fractures are at low risk and type V are at greatest). (See "General principles of fracture management: Fracture patterns and description in children".)
Orientation: Transverse, oblique, and spiral — A fracture line may have one of three possible orientations: transverse, oblique, or spiral (figure 2). Transverse fracture lines travel perpendicular to the long axis of the bone. Typically caused by a direct force causing the bone to bend, fractures with a transverse orientation are the most common fracture type.
Oblique and spiral fractures run diagonally down the long axis of a bone. Oblique fracture lines are typically shorter than those of spiral fractures, and result from twisting or rotary forces. Long oblique fractures may easily be mistaken for spiral fractures. In a true spiral fracture, a severe rotary force causes the bone to splinter, disrupting the bone in a characteristic pattern that involves a fracture line that travels in two different oblique directions (image 1 and image 2).
Displacement and angulation — Angulated or displaced fractures result in the loss of normal anatomic alignment. These fracture types commonly result in more severe soft tissue injuries than nondisplaced fractures. By convention, any fracture malalignment is described by referring to movement of the distal fragment relative to the proximal bone.
Displacement describes movement when two ends of a fracture move away from each other in an anterior-posterior plane or a medial-lateral plane. It can be quantified by the percentage of bone that is malaligned. For instance, a femur fracture where only 25 percent of the fracture surfaces remain in contact might be described as "75 percent medially displaced." Displacement can also be quantified in millimeters of displacement. Special cases of displacement occur when fracture ends are crushed together ("impacted") or pulled apart ("distracted").
Angulation refers to motion relative to the long axis of the bone. When describing angulation, both the direction and the degree (ie, angle formed by the major bone fragments) of malformation are important. The direction of angulation is best communicated by identifying the orientation of the fracture apex. In other words, the fracture fragments will form a V shape, and the apex is the point of the V. The direction of the apex is used to describe the fracture. The amount of angulation is typically reported in degrees.
Fractures with multiple parts
Comminution versus segmentation — Fractures that create more than two fracture fragments from the same bone are called comminuted (figure 2). Recognizing comminution has important implications since many comminuted fractures require surgical treatment. The degree of comminution is directly proportional to the force of injury; comminuted fractures are associated with more severe soft tissue injuries.
Segmental fractures occur when two fracture lines divide the bone into three or more large pieces. Segmental fractures are associated with poorer outcomes, the need for surgical fixation, and significant accompanying soft tissue injury.
Compression and impaction — Compression and impaction describe fractures when bones or fragments are driven into one another. Compression fractures occur in vertebral bodies and lead to a collapse of the endplates. Impacted fractures occur when forces exerted down the length of a long bone drive one fracture fragment into the other, "telescoping" them.
Open versus closed fractures — Open fractures are those in contact with the outside environment (ie, open to air), and represent orthopedic emergencies requiring immediate irrigation and debridement in the operating room and treatment with intravenous antibiotics. This decreases the risk of osteomyelitis and other infectious complications. In addition to infection, open fractures are associated with higher rates of compartment syndrome, neurovascular injury, and other soft tissue injuries compared with closed fractures.
Sometimes open fractures are obvious, as the bone can be seen protruding through the skin. More often, skin covers the involved bone, leaving a small skin laceration or puncture wound as the only sign. A careful examination of the wound is necessary.
Of note, hand surgeons generally do not consider minor fractures of the distal phalanx with small adjacent lacerations or nailbed injuries to be open fractures requiring emergent treatment, even though they may technically meet the definition of an open fracture.
The severity of open fractures may be classified using the following system :
●Type 1 – Puncture wound (≤1 cm) with minimal contamination and minimal muscle injury.
●Type 2 – Laceration (>1 cm) with moderate soft tissue damage.
●Type 3 – Extensive soft tissue damage with severe crush injury of muscle and massive contamination, including comminuted bone fragments (type 3A), periosteal stripping (type 3B), or arterial injury requiring repair (type 3C).
PRECISE "RADIOGRAPHIC" DESCRIPTION — Using the framework presented above, the clinician can convey a complete verbal snapshot of a fracture using few words. For providers with less experience managing orthopedic injuries, a simple Fracture Description Tool can be helpful to practice describing fractures or to make sure terminology is accurate before calling a consultant (figure 5). To use the tool, choose a word provided for each italicized category. The sentences produced should completely and precisely describe the fracture.
ADDITIONAL INFORMATION — Several UpToDate topics provide additional information about fractures, including the physiology of fracture healing, how to describe radiographs of fractures to consultants, acute and definitive fracture care (including how to make a cast), and the complications associated with fractures. These topics can be accessed using the links below:
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General fracture and stress fracture management in adults" and "Society guideline links: Acute pain management".)
SUMMARY AND RECOMMENDATIONS
●Bone is a composite structure with mineral and organic components. The mineral skeleton provides strength, stiffness, and rigidity. The organic or protein component consists primarily of type I collagen, which lends tensile strength and resiliency. The outer covering of bone, the periosteum, provides the vascular supply that plays an essential role in fracture healing. (See 'Biology of bone healing' above.)
●Following fracture, bone healing occurs in three slightly overlapping stages: inflammatory, reparative, and remodeling. Each phase is described in the text.
●Healing rates vary widely according to patient age, comorbidities, and other factors such as thyroid and growth hormone levels, calcitonin levels, and nutritional status. Common conditions that impair fracture healing include diabetes mellitus, arteriovascular disease, anemia, hypothyroidism, malnutrition (eg, vitamin C or D deficiencies, inadequate protein intake), excessive chronic alcohol use, and tobacco use. Specific medications may also impair fracture healing, including nonsteroidal antiinflammatory drugs, glucocorticoids, and certain antibiotics (eg, ciprofloxacin).
●The essential first step of fracture treatment is to identify precisely the type of fracture present. At a minimum, a fracture should be identified using the following:
•Name of the injured bone
•Location of the injury (eg, dorsal or volar; metaphysis, diaphysis, or epiphysis)
•Orientation of the fracture (eg, transverse, oblique, spiral)
•Condition of the overlying tissues (eg, open or closed fracture)
Other important descriptors include fracture angulation, comminution, and displacement. Each aspect of fracture description is discussed in the text; diagrams depicting common fracture types are provided (figure 1 and figure 2). (See 'Fracture description' above.)
●Open fractures are those in contact with the outside environment (ie, open to air), and represent orthopedic emergencies requiring, in the large majority of cases, immediate irrigation and debridement in the operating room and treatment with intravenous antibiotics. (See 'Open versus closed fractures' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Mark B Stephens, MD, who contributed to an earlier version of this topic review.
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