Bone fracture: what are compound fractures?

By Cristiano Antonino On May 3, 2023

A bone fracture is a medical condition that involves disruption of the integrity of a bone. It can be caused by external trauma, or it can be due to underlying diseases

There are also stress fractures, i.e. an injury caused by repeated micro-traumas that lead to a functional overload of certain areas of the body.

It is possible to distinguish different types of fractures based on their characteristics: the compound fracture, specifically, is a type of lesion in which the fragments remain aligned in their anatomical position.

The treatment of a fracture and the healing times strongly depend on the type and area involved, as well as the origin of the trauma and the patient’s medical history.

It is very important not to underestimate a bone fracture and to intervene quickly to restore the structural and functional integrity of the affected segment.

What is a bone fracture and what causes it?

In medicine, the term fracture indicates the partial or total interruption of the continuity of a bone in the body; the fracture can be of traumatic or spontaneous origin, as in the case of those due to certain pathologies, or to microtraumas caused by the repetition of certain activities.

The fragments of bone resulting from the break are called fracture stumps, while the fissure created between them is called fracture rim

In the case of a trauma, the break occurs when the entity of the traumatic event is such as to exceed the resistance limits of the bone structure.

The blow can affect the bone directly or indirectly: in the first case a fracture occurs at the very point where the force is applied, while in the case of an indirect trauma the fracture occurs at a certain distance.

On the basis of the injurious mechanism at the origin of the break, it is possible to distinguish four different types of bone fracture:

Flexion fracture: occurs when the patient is subjected to trauma that causes an unnatural curvature of the bone until it breaks, such as joint fractures in the case of blows to joints, such as elbows and knees, in which phenomena occur of flexion which cause indirect trauma to the bones of the arm or leg.
Torsion fracture: occurs when the bones undergo abrupt rotational movements, as can occur, for example, if a foot or hand is blocked.
Compression fracture: typical of the spine and vertebral bodies, it occurs when the spongy tissue is crushed during the trauma.
Tearing fracture: also called avulsion fracture, it can be caused by sudden and violent muscle contractions, which lead to bone detachment at the tendon insertion of the affected muscle.

If bone integrity is undermined by pathological processes that affect its strength, as in the case of bone tumors and osteomyelitis or in the case of patients suffering from conditions of osteopenia, osteoporosis or osteogenesis imperfecta (also called Lobstein’s disease), the the amount of force necessary to create a fracture is reduced: in these cases we speak of pathological fractures.

Finally, there are fractures due to duration or stress, which can occur when repeated microtraumas act over time on an otherwise healthy bone.

Types of bone fractures

There are various ways of classifying fractures, the main ones being:

Compound fracture or displaced fracture: based on the possible displacement of the bone segments, we distinguish compound fractures, in which the stumps remain aligned, and displaced fractures, in which there is a displacement of the bone segments from their anatomical position; depending on the displacement of the stumps, a displaced fracture can be lateral, angular, longitudinal, or rotational.
Closed fracture or open fracture: based on the integrity of the skin following a trauma, we distinguish closed fractures in which the bone remains confined within the skin that covers it, and open fractures, in which the bone segments tear apart the skin and protrude outside; the latter type of fracture carries a high risk of hemorrhage as well as infection.
Complete fracture or incomplete fracture: depending on the area involved, we distinguish complete fractures in which the lesion affects the entire thickness of the bone, and incomplete fractures that do not affect the entire diameter of the bone involved.
Stable fracture or unstable fracture: we speak of a stable fracture when, in the event of injuries, there are no forces that cause the stumps to assume an incorrect position; when instead a force, such as muscle strength, prevents contact between the two bone segments, we speak of an unstable fracture.
Simple fracture or multi-fragmentary fracture: based on the number of bone fragments produced, we distinguish simple fractures, in which two distinct bone segments originate from the lesion, or multi-fragmentary fractures, in which the trauma causes the formation of numerous bone fragments. We also speak of a comminuted fracture when it is no longer possible to recognize the number of bone fragments present.

In addition, when the lesion also damages the surrounding structures such as blood vessels and nerves, we speak of a complicated fracture; a fracture can also cause muscle, tendon, ligament, vascular, nervous, visceral or skin injuries.

Fractures can also be classified according to the course and orientation of the bone fracture gap

In this case it is possible to distinguish:

Transverse fractures: the fracture line is placed at right angles to the longitudinal axis of the bone.
Oblique fractures: also called beak fractures, in this case the lesion crosses the longitudinal axis of the bone at an angle of less than 90°.
Longitudinal fractures: The fracture plane is parallel to the longitudinal axis of the bone.
Spiral fractures: typical of torsion fractures, in these cases the lesion is characterized by a spiral course winding around the bone.

Symptoms and complications

The symptoms of patients who suffer a compound bone fracture can be quite variable and depend on the type of fracture, the severity of the damage and the location of the lesions.

Some of the main symptoms include:

Severe pain, due to stress on the (nociceptive) nerve endings.
Reduced motility, more or less marked depending on the type and location of the fracture.
Functional impotence, i.e. the total or partial inability to use the part affected by the lesion.
Hematoma or swelling, due to swelling of the tissues and muscles surrounding the fracture.
Ecchymosis, which is a hemorrhage in the subcutaneous tissue due to the possible rupture of blood vessels.
Traumatic shock.
Bleeding, especially in the case of open fractures.

Patients also often experience fatigue, low blood pressure, and palpitations due to the pain caused by the fracture.

When a patient suffers a fracture it is very important to intervene promptly with appropriate measures, in order to completely restore the functionality of the affected area.

In fact, a bone fracture, if not treated adequately, can lead to serious complications

Some of the more frequent complications can be:

Fat embolism, i.e. fat particles can enter the bloodstream and constitute an obstacle to blood circulation, leading to pulmonary and neurological complications. Fat embolism typically occurs between 12 and 72 hours after the injury.
Venous thrombosis or embolism, i.e. thromboembolic phenomena occur that can pass into the bloodstream and reach the heart or lungs.
Nerve injury, sensory or motor paralysis can occur if a nerve is compressed by edema or a bone fragment;
Deformity of the body segment that sustained the fracture.

Diagnosis and treatment

In many cases, the diagnosis of a compound fracture can be immediate, in fact, a careful evaluation of the injured part by palpation and the analysis of the mobility of the bone stumps are enough.

However, it is always necessary to carry out further investigations such as X-rays, CT scans and MRIs to accurately determine the type and location of the lesion.

The treatment of a compound bone fracture involves, first of all, the immobilization of the affected area using external braces such as casts and splints, or using internal synthetic means such as metal plates, intramedullary nails and screws, in order to avoid further damage, decrease pain and avoid bleeding.

Stages of healing

The healing process of a compound fracture can take different times depending on the patient’s age, the type of fracture, the extent of the damage and the affected area.

If the broken bone has been aligned properly and kept still, a soft healing tissue called granulation tissue is produced after the first 1-2 months.

Later it is replaced by another harder but temporary tissue, called ossification callus, which grows around the fracture and joins the stumps.

Finally, the calloused tissue is transformed into bone thanks to the action of the osteoblasts and the deposition of calcium and phosphates.

Failure of a fracture to unionize and heal is called pseudarthrosis. In this case the bone fragments are still mobile between them, as they are united by a fibrous or cartilaginous tissue; to resolve this condition it is possible to resort to ultrasound therapy, a bone graft transplant or stem cell therapy.

After consolidation of the fracture, it may be necessary to restore muscle strength and mobility in the affected area with physiotherapy treatments.

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