Lateral epicondyle fracture (elbow)

Lateral epicondyle fractures are rare epicondylar fractures. They are much rarer than medial epicondyle fractures and represent avulsion of the lateral epicondyle. They are usually seen in the setting of other injuries ^1-3. 

Epidemiology

Incidence typically peaks in the paediatric age group (6-7 years of age) ⁷.

Mechanism

In children these injuries are believed to occur due to sudden traction on the common extensor origin by the extensor musculature. In adults lateral epicondylar fractures are usually due to a direct blow ². 

Radiographic features

Plain films usually suffice in both making the diagnosis and determining treatment. 

Plain filmradiograph

The key to correct interpretation of paediatric elbow injuries is an understanding of the order and age at which the various secondary centerscentres of ossification become visible (see ossification centerscentres of the elbow). 

Before the apophysis begins to ossify (10-11 years of age), soft tissue swelling may be the only finding, and the degree of displacement cannot be evaluated on plain films. 

When ossification is present then care must be taken in not over-calling separation, on account of the apophysis beginning its ossification laterally, and as such the gap between the ossified component and the rest of the humerus can be considerable ².  Comparison to the contralateral elbow may be of benefit. 

Certainly, if the ossification centercentre is displaced such that it lies distal to the growth plate between the metaphysis and centercentre of ossification for the capitellum, then significant displacement is present. 

It should also be noted that in children the ossification centre can undergo up to 180 degrees of rotation such that the physeal surface is most superficial ³. 

As the late sequelae, there may be the presence of lateral spurring (especially in children) ⁵.

Some authors suggest a better detection rate with 20 degree tilted or internal oblique radiographs ^{6, 9}.

Reporting checklist

When reporting these injuries care should be taken to ensure that one is not looking at normal ossification of the lateral epicondyle. If satisfied that it is indeed displaced then the degree of displacement should be commented upon, as well as whether or not the ossification centercentre is within the joint. Any rotation of the centre of ossification should also be commented upon. 

The other centerscentres of ossification of the elbow should be reviewed to ensure that they are age appropriate. 

Treatment and prognosis

Undisplaced or minimally displaced injuries can be treated conservatively ¹. 

In significantly displaced fractures, rigid internal fixation allowing early mobilisation is an option although conservative management for these patients also is an option ^1-2. Even in a pseudoarthrosis occurs (non-union) most patients are asymptomatic; if symptoms do occur later surgical intervention can be carried out ^1-2. 

If the the ossification is displaced into the joint then operative intervention is required ².

In general young patients have little subsequent impairment and asan injury to the growth plate between the lateral epicondylar centercentre of ossification and the rest of the humerus does not contribute to bone length, growth arrest is not an issue ¹. 

See also

• upper limb dislocations
• avulsion injuries