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Supracondylar fractures of the humerus can be hyperextension or hyperflexion injuries. This forms the basis for the general classification of supracondylar fractures. Extension fractures are the most common and occur after a fall on the palm of the dorsiflexed hand, with the elbow in extension. Flexion injuries are generally caused by an impact on the olecranon with the elbow in flexion and account for 5% of all supracondylar fractures. The supracondylar fracture lies typically at the level of the coronoid fossa of the humerus and extends transversely through the medial and lateral columns. The bone in this area is weaker during the last part of the first decade of life due to metaphyseal remodelling. The thinnest bone is found at the base of the olecranon fossa, where the tip of the olecranon is forced during hyperextension. In addition, the elastic epiphyseal and articular cartilage of the distal segment serves to transfer the force of hyperextension to the supracondylar region. This unique predisposition of the juvenile elbow to fracture from a hyperextension mechanism has been demonstrated in two cadaver studies. Age is the key factor in determining the incidence of supracondylar fractures. Childrens supracondylar fractures occur primarily in the first decade. The incidence increases during the first 5 years of life, peaks at 5d8 years of age and decreases until the age of 15, after which it is |
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