FRACTURE SITES

In the initial evaluation of any fracture, the examiner must identify the specific location of the fracture within the bone (see Plate 7-21). The different areas of bone heal with different mechanisms and at different rates. Fractures may occur in the shaft (diaphysis), metaphysis, joint (intra-articular fracture), growth plate (physis), or epiphysis. Fractures of the shaft and metaphysis heal in very dissimilar ways. Diaphyseal bone usually heals by the formation of an external bridging callus, whereas metaphyseal bone healing is dominated by intramembranous ossification. In addition, the cancellous metaphyseal bone heals much more rapidly than the cortical diaphyseal bone.

Intra-articular fractures involve the articular surface of the bone, and this involvement has important implications for both treatment and prognosis. The articular surface must heal with anatomic congruity to minimize the risk of post-traumatic osteoarthritis. Epiphyseal (growth plate) fractures are quite common in children and heal more rapidly than fractures in adults.

TYPES OF DISPLACEMENT

The initial evaluation of any fracture, in addition to assessment of the degree of soft tissue injury and the location in the bone, must determine the degree of fracture displacement. All fractures must be described as nondisplaced or displaced (see Plate 7-22). Nondisplaced fractures are difficult to diagnose because there is no associated deformity except soft tissue swelling. Indeed, many nondisplaced fractures are overlooked or mistaken for a simpler injury such as a mild or moderate sprain. All patients with a musculoskeletal injury who complain of pain and exhibit swelling, ecchymosis, and point tenderness at the injury site should undergo radiographic evaluation to rule out disruption of the underlying bone architecture. If not appropriately treated, nondisplaced fractures often result in serious disability.