Dislocations of the elbow

Introduction

Elbow dislocation, along with glenohumeral and patellofemoral joint dislocations, is one of the three most common large joint dislocations. It is also the second most common site for non-prosthetic joint dislocation. The elbow joint is a hinge-like articulation involving the distal humerus and proximal radius and ulna. Owing to its strong muscular and ligamentous supports, the joint is normally quite stable and rarely requires operative intervention, even for acute instability after dislocation.

Elbow dislocations can be classified as either anterior or posterior. Posterior dislocation is the most common type and can be further divided into postero-medial and postero-lateral. It usually results from a fall on the outstretched hand with some degree of flexion or hyperextension at the elbow. The radius and ulna commonly dislocate together. Similarly, anterior dislocation can also be divided into anteromedial or anterolateral. This type is less common and is usually due to a direct blow to the dorsal side of the elbow.

Uncommonly, the radius or ulna alone may dislocate at the elbow. In such cases there is always a fracture of the other bone. One common example is the Monteggia fracture, where anterior or posterior radio-humeral dislocation occurs alongside a fracture of the proximal third of the ulnar shaft ( Fig. 4.3.1 ). A rarer example is a posterior ulnar-humeral dislocation with fracture of the radial shaft. There is a specific type of injury of the elbow, the ‘terrible triad’, characterized by elbow dislocation, radial head or neck fracture and coronoid fracture. Therefore although elbow dislocations may appear to be isolated, it is essential to look for associated intra-articular or shaft fractures.