Diagnosis

Although these radiographs appear to be normal, the patient obviously has something wrong with his elbow. Diagnosing a sprain of the elbow is a pitfall that should be avoided. When the patient has obvious clinical findings around the elbow, examine the radiographs carefully for a posterior fat pad sign, a supracondylar fracture, a radial head fracture, and misplaced ossification centers that may represent fractures. In this case, none of these are visible on the radiographs, which should lead one to be suspicious of an occult fracture not radiographically visible. In this case, two oblique views of the elbow were obtained.

View oblique films

The first oblique view does not reveal much, but the other oblique view shows an obvious fracture of the lateral (external) condyle. This diagnosis makes sense based on the patient's physical exam. This fracture typically produces a larger than expected degree of swelling. One might consider that this fragment over the lateral condyle is the ossification center of the external epicondyle (lateral condyle); however, this ossification center does not have this appearance. In addition, this ossification center is the last to appear in the elbow. The ossification center of the olecranon appears before this. Since the olecranon's ossification center is not visible (see lateral view), the external epicondyle will not be ossified yet. The mnemonic CRITOE is useful to remember the sequence of appearance of the elbow ossification centers (Capitellum, Radial Head, Internal epicondyle, Trochlea, Olecranon, and External epicondyle). See Case 11 (Elbow Ossification Centers in a Child) for more details. In retrospect, this fracture is visible on the AP view. Go back and examine the lateral condyle region of the AP view. Magnify the view to examine it closely.

View AP and Lateral view above:

Discussion & Teaching Points:

1. A swollen elbow usually contains a fracture injury. In some instances, a joint effusion (posterior fat pad sign or enlarged anterior fat pad sign) can be seen in the absence of a visible fracture. Occult fractures may still be present in such cases. It is prudent to treat such an injury as a non-displaced fracture, with a splint, sling, and follow-up with a primary care physician or orthopedic surgeon.
   
   
2. When uncertainty exists, careful examination of the patient will often help guide your review of the radiographs and the need to request special views.
   
   
3. Occult fractures in the elbow may be difficult to identify. Areas that are commonly fractured include the supracondylar region, the radial head, and the lateral condyle
   
   
4. Even with special views, not all fractures are radiographically visible. Other imaging modalities such as bone scanning, CT scanning, and MRI scanning have all identified fractures in patients with normal radiographs. Normal radiographs are not able to totally rule out fractures. It is often beneficial to advise patients of the limitation of radiographs. In any musculoskeletal injury, persistent pain should prompt the patient to seek medical care even if their initial set of radiographs was normal. Orthopedic referral, a repeat set of radiographs, or an advanced imaging modality should be considered in injuries resulting in persistent pain.
   
   
   
5. It is useful to include a standardized instruction sheet to patients whenever radiographs are obtained in the emergency department. This instruction sheet should explain the possibility of interpretation errors, differences of opinion in the radiographic interpretation, the limitation of radiographs, and instructions for follow-up. Such an instruction sheet can substantially reduce the number of patient complaints regarding misinterpreted radiographs and reduce the ED's liability potential.

An example of such an instruction sheet follows:

1. The emergency physician has read your X-ray as: Normal elbow (example)
   
   
2. Large abnormalities requiring urgent care are generally obvious and, therefore, this is unlikely at this point. An emergency physician can find most of the problems on an X-ray, but the emergency physician is not a specialist in radiology.
   
   
3. To be sure, we will have the hospital radiologist (X-ray specialist) read your X-ray on the morning of the next working day (Monday through Saturday). If there is an important difference in the X-ray reading, we will try to call you or your doctor, but this doesn't always happen. To double check us, please call your physician or the hospital clinic (949-8899) to find out how your X-ray is being read by the radiologist. If you call the hospital X-ray department directly, they will not give you the reading over the phone since the medical reading is not understood by most people. It must be done through your doctor.
   
   
4. When you call your doctor or your doctor's office nurse, tell him/her that you came to the Emergency Department where some X-rays were taken, and you were told to call your doctor to double-check the X-ray reading with the hospital radiologist. The most common things that are missed on X-ray readings are tiny fractures (cracks, chips, or hairlines) and small areas of infection (bronchitis, pneumonia, bone infection, etc.).
   
   
5. To be sure that these problems are not there, it is important that you contact your physician so that you will receive the proper care for this condition.
   
   
6. For injuries, pain that lasts for more than a week or pain that doesn't get better after two days could mean that you have a hidden broken bone, even if your X-rays are normal (X-rays cannot find all broken bones). See your doctor for an examination of the area. Another set of X- rays may be needed.
   

Copyrighted:Radiology Cases in Pediatric Emergency Medicine Volume 7, Case 9 Loren Yamamoto, MD, MPH, Professor of Pediatrics, University of Hawaii John A. Burns School of Medicine.Loreny@hawaii.edu

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Last created on 01-07-2006