Distal Humerus-Distal Humerus Overview

Distal Humerus Overview

Pdf Summary

Distal humerus fractures constitute about 33% of all humerus fractures and are characterized by complex articular and metadiaphyseal anatomy. Immobilization of the elbow can lead to loss of motion. The functional anatomy of the distal humerus includes a hinged joint with a single axis of rotation, trochlear axis, and the trochlea acting as the center point with lateral and medial columns. The distal humerus has forward angulation, anterior angulation of about 30 degrees, and valgus angulation of about 3-8 degrees externally rotated. The surgical anatomy of distal humerus fractures involves the medial and lateral columns, which diverge from the humeral shaft at a 45-degree angle and support the "distal humeral triangle." Mechanisms of injury are related to the position of elbow flexion when the load is applied, and evaluations involve physical exams, neurologic and radiographic evaluations. Distal humerus fractures are classified using the AO Long Bone System into extra-articular fractures, partial articular fractures, and complete articular fractures, further subdivided into specific fracture types. Treatment principles involve anatomic articular reduction, stable internal fixation of the articular surface, restoration of articular axial alignment, stable internal fixation of the articular segment to the metaphysis and diaphysis, and early range of motion of the elbow. Fixation methods depend on the fracture pattern and surgeon preference, including locked or non-locked plates, dual plates, and parallel or 90-90 plating. Other surgical options can include total elbow arthroplasty or the "bag of bones" technique, while cast or brace immobilization is suitable for non-displaced stable fractures. In elderly patients, neither fixation failure, nonunion, nor ulnar nerve palsy increase with age, making ORIF a viable option. Total elbow arthroplasty is also a viable treatment option for elderly patients with distal humerus fractures.

Keywords

Distal humerus fractures

articular anatomy

elbow immobilization

surgical anatomy

fracture types

internal fixation

range of motion

total elbow arthroplasty

cast immobilization

elderly patients