Chapter 11. Classification of fractures and dislocations

Classification of fractures helps to systematize signs of damage, possible options for displacement of fragments, complications, approaches to treatment and prognosis of its outcomes. There are many classifications of fractures based on a wide variety of features.

Flatness of fracture

When assessing the plane of the fracture and its relation to the axis of the diaphysis, the following are distinguished (Fig. 11.1):

• transverse fracture - it is in the same plane, close to the perpendicular to the axis of the diaphysis;
• oblique fracture - the plane of the fracture deviates from the perpendicular to the bone axis by 30° and more;
• torsion fracture - the fracture is not located in one plane but spatially, imitating the turns of the screw (such fractures cannot be called spiral: the spiral is in the same plane, and the screw has a spatial location);
• comminuted fracture distinguishes itself by the fact that at different fracture planes, it has an additional fragment - a splinter;
• a multi-splintered fracture is distinguished by the presence of two or more fragments;
• a marginal fracture is characterized by damage to the edge of the bone without disrupting its continuity (a variant of the marginal fracture is an avulsion fracture, in which a fragment of a bone breaks off together with a tendon or ligament attached to it as a result of their tension);
• perforating fracture occurs with a sharp local impact of considerable force (more often with a gunshot wound).

Fig. 11.1. Classification of fractures according to the plane of the fracture: 1) transverse; 2) oblique; 3) helical; 4) comminuted; 5) multi-splintered; 6) marginal; 7) tear-off; 8) perforating

Displacement of fragments

The primary displacement of fragments (Fig. 11.2) is due to the action of the traumatic force. Following the primary displacement, a displacement may occur, which depends on the traction of the surrounding muscles: in width, at an angle, rotational, in length.

Fig. 11.2. Variants of displacement of bone fragments: 1) in width; 2) at an angle; 3) rotary; 4) in length; 5) impaction

Displacement of fragments in width leads to a disturbance of intramedullary blood circulation.

There are: 0 (zero) degree - no displacement, I degree - displacement of no more than ½ of the diameter of the bone, II degree - displacement of more than ½ of the diameter but with the preservation of the contact of bone fragments, III degree - displacement of the entire width of the bone with a complete impairment of intramedullary circulation (Fig. 11.3).

Fig. 11.3. The severity of displacement of bone fragments in width: a) no displacement; b) I degree (up to ½ of the width); c) II degree (>½ width); d) III degree (full width)

Deflection under an angle is easy to diagnose by the deformation of the segment axis and is most easily eliminated by traction along the axis with angular deviation.

Rotational displacements are more difficult to diagnose than others; they are more typical for helical fractures, although they often occur with other plane of the fracture.

Displacement along the length is possible with the divergence of fragments with the formation of diastasis and overriding of bone fragments. The latter type of displacement is more common. A displacement along the length of the transverse fracture with the overlap of fragments is possible only with the III degree of displacement.

With oblique and helical fractures, a displacement in length is possible without a complete displacement in width. In the latter case, a displacement in length is always combined with a rotational offset. Displacement with the divergence of fragments is possible with the separation of a bone fragment with a ligament or tendon (with a fracture of the ulnar process, patella, ankle, tuberosity of the tibia, etc.). There may also be iatrogenic reasons for the divergence of fragments along the length as a result of excessive traction during treatment.

Formally, a variant of displacement along the length is also impacted fracture, although the displacement is minimal. Impacted fractures are possible only where cancellous bone is expressed (for example, vertebral bodies, metaphyses, and epiphyses of long bones). They are most favorable for subsequent reparative bone regeneration. If the angular displacement with an impacted fracture does not lead to functional impairment, then its splitting is contraindicated and should be equated to complications.

Fracture localization

Within the tubular bone, fractures are located in the diaphysis, metaphysis and epi-physis. The most accurate restoration of anatomy should be carried out in case of a fracture with a transition to the articular surface. It is also important to divide the fractures into extra-articular and intra-articular. The transition of the fracture line to the articular surface entails damage to the articular cartilage, and an increased likelihood of developing post-traumatic osteoarthritis. The displacement of bone fragments in an intra-articular fracture must be completely eliminated in order to achieve a good treatment result.

For fractures of a number of localizations, there are special classifications focused on the anatomical and physiological features of these segments. They will be discussed in the relevant sections of the textbook.

Possibility of closed matching of fragments (reposition)