The elbow does not have inherent bony stability; it depends on the ligaments and capsule to maintain alignment of three joints: the ulnohumeral joint (stabilized by the ulnar collateral ligament and the lateral ulnar collateral ligament), the radio-humeral joint (stabilized by the radial collateral ligament), and the proximal radio-ulnar joint, stabilized by the annular ligament and the interosseous membrane. The three joints of the elbow allow motion in several dimensions: flexion, extension, pronation, and supination (Fig. 9-1).

Elbow x-rays can be difficult to read in young children as the radial head ossification center isn’t visible until around age 3, and the olecranon not until around 8 years in girls, 10 years in boys—fractures or physeal injury can be easily missed on x-ray. Ultrasound is being used more commonly for evaluation and treatment of pediatric elbow fractures as it does not expose the child to radiation and can give a better picture of unossified bone (Fig. 9-2). MRI arthrogram can also better delineate fractures and displacement around the elbow.

In children, the proximal radial physis is intra-articular; fractures that are bathed in synovial fluid typically take longer to heal and may go on to non-union even if adequately reduced. The physis is also at risk for premature closure secondary to fracture, fracture reduction, and/or fixation that crosses the physis.

The olecranon has an apophysis at its proximal end that may develop chronic traction injuries in athletes. The triceps tendon, with or without the apophysis, can be completely avulsed with forceful triceps contraction (Fig. 9-3).

It is also important to note that the blood supply to the radial head is mainly from the periosteal blood vessels running from distal to proximal—this tenuous blood supply may be disrupted by fracture or surgical dissection, leading to avascular necrosis (AVN), which can have a long-term deleterious effect on elbow function and growth of the radius. Repetitive trauma to the elbow, as is seen in pitchers and gymnasts, can also disrupt radial head blood supply and cause abnormal growth of the radial head and an incongruent joint.

The brachial artery, median nerve, and radial nerve anterior to the elbow joint are at risk for stretch injury with a proximal forearm fracture or elbow dislocation. The ulnar nerve, running medially just behind the medial epicondyle, may be stretched, torn, or entrapped in the joint at the time of injury or during reduction. The posterior interosseous nerve, coursing anterior to the radial head and anterolateral to the radial neck, can easily be injured when the proximal radius is fractured or dislocated (Fig. 9-4).

As discussed in the prior chapter, it can sometimes be difficult to distinguish between an injured and infected elbow in a young child. Be wary if you do not see a clear fracture but there is a “sail sign” or fluid in the joint on x-ray (Fig. 9-5). This may indicate an occult fracture, but the fluid creating the sail sign may also be a sign of infection (pus) in the joint. If there is any question, check bloodwork: CBC, sedimentation rate, and C-reactive protein. Putting an infected elbow in a cast for 3 weeks has resulted in disaster.

Once the area of concern is identified, a skin exam will rule out an open fracture, with the standard neuro-vascular exam then performed (see Chapter 8 for details). Do this portion of the exam before you touch the elbow; if the child starts screaming, the rest of the exam is very difficult if not impossible (Fig. 9-6). In a relaxed child, the fracture location can be estimated by gentle palpation and pronation/supination of the forearm.

Because additional fractures in the same limb are common, always check the joint above and below the area of concern. The contralateral elbow should be examined to determine the normal anatomy and motion for each individual. A child who has a more cubitus valgus due to normal anatomy or prior fracture is more likely to sustain a proximal radius fracture whereas a child with a varus carrying angle is more prone to lateral condyle fracture.

Fortuitous reduction can occur when the x-ray technician supinates the arm to obtain an AP x-ray. Because the x-rays are usually normal, you must rely on the history and your exam to reach the diagnosis. The classic teaching is to reduce by supinating the flexed elbow and you will feel a click as the subluxed radial head reduces. Often the elbow must be flexed above 90 degrees with firm supination to achieve reduction (Fig. 9-11). There are four “low quality” studies reviewed by Krul in the Cochrane Database of Systematic Reviews that looked at flexion and hyper-pronation of the pulled elbow as a less painful and more effective reduction technique; however, better studies need to be done before this becomes standard of care.

After the typical reduction, the child often stops crying, seems more comfortable, and starts to move the arm within a minute or two. No immobilization is required, but the parents should avoid pulling the child or lifting them by the arm for the next several years.

Recurrence is relatively common, and a child may have repeated subluxations in the first 3-4 years of life. Repeat injuries are treated in the same fashion as first-time subluxations, with the problem gradually
disappearing by age 5 years; the younger the child, the greater the risk for recurrent subluxation.

A few times a year, one is faced with a case that does not seem to reduce despite ruling out other causes and utilizing the correct reduction maneuver. When convinced that we have a true unreducible nursemaid’s elbow (not an occult septic elbow or fracture), our approach includes casting the child in a position that technically will reduce the subluxation (elbow flexed to 100 degrees, full supination) for 3 weeks. This usually solves the problem.

There have been a few case reports in the literature of pulled elbows that were completely irreducible with closed means. In these cases, surgical exploration demonstrated that the annular ligament had slipped past the equator of the radial head and become trapped in the radiocapitellar joint. We have no experience with such cases.

Elbow dislocations are described by the position of the radius and ulna in relation to the distal humerus (anterior, posterior, medial, or lateral). They are further classified based on whether or not the proximal radio-ulnar joint remains intact (Table 9-1). Posterolateral dislocations, by far the most common in reported series, are thought to be caused by a fall on the outstretched hand with the elbow extended. Typically the radio-ulnar articulation remains intact with only rare instances of divergent dislocation (radius and ulna separated).

The dislocation should be reduced as soon as possible to relieve pain and improve circulation. Conscious sedation helps to relax the muscles adequately for an atraumatic reduction. An easy method for reduction includes placing the child prone with the elbow flexed over the edge of the bed so that the forearm hangs vertically downward. When the child relaxes, a little pressure over the olecranon with correction of any sideways displacement usually reduces the elbow (Fig. 9-14).