Classification of fractures of the clavicle in adult according to Robinson [114

A new classification was developed based on radiological review of the anatomical site and the extent of displacement, comminution and articular extension out of 1000 patients. There were satisfactory levels of inter- and intraobserver variation for reliability and reproducibility. Fractures of the medial fifth (type 1), undisplaced diaphyseal fractures (type 2 A) and fractures or the outer firth (type 3 A) usually had a benign prognosis. The incidence of complications of union was higher in displaced diaphyseal (type 2B) and displaced outer-fifth (type 3B) fractures. In addition to displacement, the extent of comminution in type-2 B fractures was a risk factor for delayed and nonunion.

Three different areas of fracture were identified: the diaphysis and the medial and lateral ends (Fig. 40). Type I was the fifth of the bone lying medial to a vertical line drawn upwards from the centre of the first rib. Type 3 was the fifth of the bone lateral to a vertical line drawn upwards from the centre of the base of the coracoid process, a point normally marked by the conoid tuberosity. Type 2 was the intermediate three-fifths of the diaphysis.

Fractures were also divided into subgroups A and B depending on displacement (greater or less than 100% translation) of the major fragments. This is often difficult because of the sigmoid shape of the clavicle, particularly at the ends of the bone, but weight-bearing, oblique, 30° caudal-tilted or modified axial views were used in cases in which uncertainty existed.

Type-IA and type-IB fractures were further subdivided into extra- or intraarticular; type-2A fractures were subdivided according to the presence of angulation, but in all these injuries there was residual bony contact. In the type-2B subgroup there was no residual contact between the major fragments and variable degrees of shortening which was usually apparent both clinically and radiologically. Two further subgroups of type-2B were simple or wedge comminuted fractures (type 2B1) and isolated segmental or segmentally comminuted fractures (type 2B2). Type-3A and type-3B fractures were also subdivided according to articular involvement. Displacement in type-3B injuries showed a characteristic pattern of elevation and posterior displacement of the shaft fragment, with either a simple oblique configuration or with avulsion of an inferior bone fragment.

Type-l fractures were uncommon, at 2.8% of the fracture population; most were undisplaced and extraarticular (type IA 1). Type-2 injuries were the most common (69.2%) and most were displaced (type 2B); the most common was type 2B1. Of the type-2B1 fractures, 28.9% had wedge comminution and the remainder was simple. Type-2B2 fractures had an incidence of 25.5%. Of the type 2B2 injuries 21.1% were the isolated segmental type and the remainder was comminuted segmental. Type-3 fractures. 28% of all were predominantly undisplaced (type 3 A).

Type-I and type-2 fractures were seen in a younger population and with a greater M:F ratio than type-3 fractures. Type-2A2 fractures occurred in a younger population than the other fractures; all but two

Clavicle Fracture Rockwood
Fig. 40. Type-1, type-2, and type-3 clavicular fractures

were in patients aged 13 to 25 years. Type-2 fractures were mainly caused by sport or RTAs whereas simple falls were the commonest cause of type-I and type-3 fractures.

10.6 Classification of nonunion of clavicular fractures according to Neer [98]*

■ Type 1 was characterized by a false joint, with hyaline-like cartilage capping the dense bone ends, and possibly joint fluid.

■ Type 2 lesions consisted of resorption of the bone adjacent to the fractures, resulting in tapering bone ends, obliteration of the medullary canal, and a gap which was filled with fibrous tissue.

10.7 Classification of epiphyseal fractures of the proximal end of the clavicle according to Rockwood and Wirth [115a]*

The epiphyseal fractures of the proximal end of the clavicle have to be differentiated from Grad III sterno clavicular joint dislocations (Fig. 41a,b).

+1 0

Post a comment