Pediatric Elbow Fractures When looking at radiographs of the elbow after trauma a methodical review of the radiographs is needed . You should ask yourself the following important questions. Is there a sign of joint effusion? After trauma this almost always indicates the presence of hemarthrosis due to a fracture (either visible or occult). Is there a normal alignment between the bones? In children dislocations are frequent and can be very subtle. Are the ossification centers normal? Is the piece of bone that you're looking at a normal ossification center and is this ossification center in the normal position. Look especially for the position of the radial epiphysis and the medial epicondyle. Is there a subtle fracture? Some of the fractures in children are very subtle. So you need to be familiar with the typical picture of these fractures. Fat Pad Sign and Joint Effusion Normally on a lateral view of the elbow flexed in 90degrees. A fat pad is seen on the anterior aspect of the joint . This is normal fat located in the joint capsule. Normal Anterior Fat Pad On the posterior side no fat pad is seen since the posterior fat is located within the deep intercondylar fossa. Positive Fat Pad Sign Distention of the joint will cause the anterior fat pad to become elevated and the posterior fat pad to become visible. An elevated anterior lucency or a visible posterior lucency on a true lateral radiograph of an elbow flexed at 90 degrees is described as a positive fat pad sign. Posterior Fat Pad Alignment There are two important lines which help in the diagnosis of dislocation and fracture These are the Radiocapitellar line and the Anterior humeral line. Radiocapitellar Line A line drawn through the center of the radial neck should pass through the center of the capitellum, whatever the positioning of the patient, since the radius articulates with the capitellum. In dislocation of the radius this line will not pass through the center of the capitellum. On the left we see, that the radiocapitellar line goes through center of the capitellum on every radiogragh even though C and D are not well positioned. Notice supracondylar fracture in B. On the left more examples of the radiocapitellar line. The right lower image shows an obvious dislocation of the radius. Anterior Humeral Line A line drawn on a lateral view along the anterior surface of the humerus should pass through the middle third of the capitellum. This line is called the Anterior Humeral line. In cases of a supracondylar fracture the anterior humeral line usually passes through the anterior third of the capitellum or in front of the capitellum due to posterior bending of the distal humeral fragment. On the left the anterior humeral line passes through the anterior third of the capitellum. This indicates that the condyles are displaced dorsally (i.e. supracondylar fracture). Ossification Centers There are 6 ossification centers around the elbow joint. They appear and fuse to the adjacent bones at different ages. It is important to know the sequence of appearance since the ossification centers always appear in a strict order. This order of appearance is specified in the mnemonic C-R-I-T-O-E (Capitellum Radius - Internal or medial epicondyle Trochlea - Olecranon - External or lateral epicondyle). The ages at which these ossification centers appear are highly variable and differ between individuals. It is not important to know these ages, but as a general guide you could remember 13-5-7-9-11 years. The Trochlea has two or more ossification centres which can give the trochlea a fragmented appearance. On a lateral view the trochlea ossifications may project into the joint. They should not be mistaken for loose intra-articular bodies (arrow). Common Pediatric Elbow Fractures Supracondylar Fractures These fractures account for more than 60% of all elbow fractures in children. More than 95% of supracondylar fractures are hyperextension type due to a fall on the outstretched hand: The elbow becomes locked in hyperextension. The olecranon is pushed into the olecranon fossa causing the anterior humeral cortex to bend and eventually break. Supracondylar Fractures If there is only minimal or no displacement these fractures can be occult on radiographs. The only sign will be a positive fat pad sign. Usually there is some displacement and the anterior humeral line will not pass through the center of the capitellum but through the anterior third or even anterior to the capitellum (figure). If the force continues both the anterior and posterior cortex will fracture. Gartland Type I fractures are often difficult to see on X-rays since there is only minimal displacement. Most of these fractures consist of greenstick or torus fractures. The only clue to the diagnosis may be a positive fat pad sign. These patients are treated with casting. Type III In Gartland type II fractures there is displacement but the posterior cortex is intact. There may be some rotation. These fractures require closed reduction and some need percutaneous fixation if a longarm cast does not adequately hold the reduction. Gartland type III fractures are completely dislocated and are at risk for malunion and neurovascular complications. They require reduction by closed or if necessary open means. Stabilization is maintained with either two lateral pins or medial lateral cross pin technique. Type II Malunion will result in the classic 'gunstock' deformity due to rotation or inadequate correction. Posterolateral displacement of the distal fragment can be associated with injury to the neurovascular bundle which is displaced over the medial metaphyseal spike. Nerve injury almost always results in neuropraxis that resolves in 3-4 months. Vascular injury usually results in a pulseless but pink hand. Conservative management and vascular intervention have the same outcome. A pulseless and white hand after reduction needs exploration. Lateral Condyle Fractures This fracture is the second most common distal humerus fracture in children. They occur between the ages of 4 and 10 years. These fractures occur when a varus force is applied to the extended elbow. They tend to be unstable and become displaced because of the pull of the forearm extensors. Treatment strategies are therefore based on the amount of displacement. Undisplaced fractures are treated with a long arm cast. These fractures must be carefully monitored as they have a tendency to displace. At follow up both AP and Oblique views are taken after removal of the cast. Since these fractures are intra-articular they are prone to nonunion because the fracture is bathed in synovial fluid. Lateral condyle fractures are classified according to Milch. They are Salter-Harris IV epiphysiolysis fractures. Most are Milch II fractures that travel from the lateral humeral metaphysis above the epiphysis and exit through the lateral crista of the trochlea leading to an unstable humeral ulnar articulation. Once displaced fractures consolidate in a malunited position, treatment is difficult and fraught with complications. For this reason surgical reductions are recommended within the first 48 hours. Open reduction is indicated for all displaced fractures and those demonstrating joint instability. The diagnosis of a lateral condyle fracture can be challenging. Fracture lines are sometimes barely visible . Remembering the fact that the lateral condyle fracture is the second most common elbow-fracture in children and because you know where to look for will help you. Lateral Condyle Fracture Examples Proximal Fractures of the Radius In adults fractures usually involve the articular surface of the radial head. In children however it's the radial neck that fractures because the metaphyseal bone is weak due to constant remodelling. Usually it is a Salter Harris II fracture. If there is no displacement it can be difficult to make the diagnosis. Olecranon Fractures Olecranon fractures in children are less common than in adults. They are associated with radial neck fractures and radial dislocations. Monteggia’s Fracture Ulna fracture with radial head dislocation. Closed reduction. 4 Types: Galleazzi’s Fracture Radius fracture with radioulnar joint dislocation. Fall onto extended arm. Anterior interosseous nerve. Treated with open reduction. I - Extension type (60%) - ulna shaft angulates anteriorly (extends) and radial head dislocates anteriorly. II - Flexion type (15%) - ulna shaft angulates posteriorly (flexes) and radial head dislocates posteriorly. III - Lateral type (20%) - ulna shaft angulates laterally (bent to outside) and radial head dislocates to the side. IV - Combined type (5%) - ulna shaft and radial shaft are both fractured and radial head is dislocated, typically anteriorly