Table of Contents
Classification and Types of Bone Fractures
The fracture can be closed or open according to the interruption of the overlying skin. Open fracture with disrupted overlying skin is more susceptible to infection from the external environment and need special management and prolonged recovery. This is an orthopedic emergency requiring debridement, irrigation in the OR and broad spectrum antibiotic prophylaxis.
Fractures can also be classified according to the orientation into transverse, oblique or spiral fractures.
Spiral fractures present as two long fracture lines at two different directions caused by a severe rotatory force. According to the location, fractures can affect the diaphysis, metaphysis of the epiphysis of long bones.
Intra-articular fractures usually need open reduction and fixation for optimum healing and to preserve the joint function.
Displaced and angulated fractures are associated with more soft tissue injury. They result from loss of the normal anatomic alignment between the distal and proximal segments of a fractured bone.
Angulated fracture forms a shape of V while displaced segments move away from each other.
Segmental fractures occur with two fracture lines and three or more large bone segments that separate from the original bone.
Comminuted fracture occurs when two or more fracture segments result in the same bone with small bone fragments that might pierce the skin. Both types of comminuted and segmental fractures need surgical fixation and soft tissue debridement according to the extent of the injury.
Pathological fractures result from a pathological process that weakens the bone over time and leads to break in the integrity of bone with minor trauma. Pathological fractures can be due to malignancy, osteoporosis, infection or bone cysts.
Insufficiency fractures are a special type of pathological fractures which occur as a result of osteoporosis. They are also called fragility fractures.
Stress fractures are common in athletes and marching soldiers. They result from repetitive load or force on the bones without allowing for rest or healing of the bone as a result of micro-fractures of moderate forces.
The healing process
The healing of bones is similar to any healing process in different injured tissues but without scar formation. New bone is formed to preserve the same function of the skeleton support. It depends on patient’s age, peripheral circulation, comorbidities, medications e.g. steroids, alcohol, smoking and associated infection or complications. Healing starts with the inflammatory phase then the reparative phase and finally remodeling.
It is crucial to stabilizing the fractured bone segment in the first two phases to allow for the formation of new blood vessels.
Inflammatory phase lasts for few weeks and is characterized by a hematoma collection at the fracture line with resorption of the bone edges that lost their blood supply. It is similar to classic inflammation with swelling, tenderness, and redness all powered by cytokines release. Osteoprogenitor cells appear from the transformation of multipotent mesenchymal cells and start bone formation.
The next phase is characterized by callus formation which is invaded by newly formed blood vessels. This phase continues for months with cartilage and bone formation. The endochondral bone at the fracture site is formed over the callus which is formed by cartilage that ossifies and hardens later on. The clinical union is achieved in this phase by the disappearance of pain with movement of the affected limb and stabilization of the bone segment with movement.
When clinical union occurs, remodeling starts and lasts for years to make the bone back to its original size and format. It is characterized by ossification of the cartilaginous callus.
Clinical Picture of Bone Fractures
Careful history taking and assessment of the mechanism of injury is extremely important to help with fracture evaluation and exclude other injuries.
Examination of Bone Fractures
Gentle palpation of the injured area is necessary to know about any displacement and exclude other injuries. The examination should involve the fracture site, the distal and proximal joint and any possible other injuries. Sensory and motor evaluation of the injured limb is done to evaluate the neurovascular supply after the fracture and following reduction.
Imaging of Bone Fractures
It is considered the primary imaging modality of choice for diagnosis fractures.
Some other fractures may need another view e.g. scaphoid view for scaphoid fractures. X-ray radiographs may fail to reveal fracture line in some specific fractures e.g. stress fractures, scaphoid fracture, and hip fractures. In this case, CT or MRI is beneficial in revealing the fracture line otherwise managing the case with fixation and performing follow up radiographs after one or two weeks to evaluate for fracture line.
It can be used in the emergency department or sports medicine with high sensitivity and specificity. Another advantage is the lack of ionizing radiation.
CT and MRI are more beneficial especially in stress fractures or spinal fractures with good visualization of the fracture site and possible displacement.
Management of Bone Fractures
A thorough evaluation for associated injuries using advanced trauma life support is the first step in trauma patients. Evaluation starts with airway maintenance, breathing support and circulation support. Adequate pain management is also necessary for all patients. Pain management can be achieved by application of ice, immobilization of the injured limb, analgesic medications and regional nerve block. For fracture immobilization, splinting is the initial step unless the neuro vascular supply distal to the fracture is interrupted. Immobilization is performed in the scene before the patient is transported to reduce the pain and prevent complications of displacement and soft tissue injury. Reduction of the fractured bone should be attempted first in case of absent peripheral pulses, altered sensation or change of the skin color distal to the fracture.
For fracture immobilization, splinting is the initial step unless the neurovascular supply distal to the fracture is interrupted. Immobilization is performed in the scene before the patient is transported to reduce the pain and prevent complications of displacement and soft tissue injury. Reduction of the fractured bone should be attempted first in case of absent peripheral pulses, altered sensation or change of the skin color distal to the fracture.
Open fracture requires vigorous irrigation with saline followed by surgical debridement of necrotic tissues, tetanus prophylaxis, and intravenous antibiotics.
Complications of Bone Fractures
Acute onset complications following fractures can range between neurovascular injury, fat embolism, deep venous thrombosis, and compartment syndrome.
Arterial injuries can be fatal in places that can accommodate plenty of blood loss. Femur fractures and pelvic fractures are particularly common with an injury of major blood vessels leading to enormous bleeding. Arterial injury can also lead to interruption of blood supply distal to the fracture.
The immediate reduction is crucial with absent peripheral pulses following fractures. angiography is the definitive way for diagnosis of arterial injury even with intact clinical evaluation. Nerve injury can be acute following the fracture or delayed complication of casting.
Abnormal sensation distal to the fracture with adequate analgesia is a sign of nerve injury. It can range from neuropraxia characterized by only physiological interruption of the nerve signals and heals in about 2 months to Neurotmesis characterized by anatomic disruption of the nerve fibers.
Deep vein thrombosis is a common complication following fractures which can progress to fatal pulmonary embolism. Adequate prophylaxis is indicated in all patients with prolonged immobilization to avoid thromboembolic events.
It occurs most commonly in the lower limb with a fracture of the femoral shaft. Patients present with dyspnea, tachypnea, hypoxemia and a petechial rash. It may progress to a fatal respiratory failure or neurological complications.
It is characterized by increased pressure in limb compartment following fractures due to bleeding, edema or tight casting. It is common with fractures of the tibia and radius. Complications can progress to gangrene. It is characterized by increasing pain out of proportion to the fracture. The pain can be elicited with passive movement or stretching of the muscles. When suspected, casts and bandages should be removed immediately and fasciotomy should be planned to save the limb.
It includes Osteomyelitis, nonunion which is common with scaphoid fracture and femoral neck fractures, premature osteoarthritis and complex regional pain syndrome.