An 18 month old male was brought to a rural emergency department because of pain in his right hip and refusal to walk since yesterday. He was well until he was walking up a wheelchair ramp and somehow fell off the side of it onto his right leg. Since then, his mother noted him to be in pain whenever she moves that leg. He refuses to walk.
As best as she can tell, his pain appears to be in the right hip or thigh. He has no history of fever, chills, other joint pains, joint swelling, or skin infections. He was given acetaminophen for pain control but this does not seem to help much.
T37.0 (tympanic), P110, R28, BP 100/55.
He was alert in no distress. He does not appear to move his right hip very much. He does not appear to have a position of preference for the right hip. Specifically, he does not favor the external rotation position. He moves his toes well. He moves his entire left lower extremity well. He seems to be tender around the right thigh and possibly the hip, but it is difficult to localize this with certainty as his mother has noted as well. No joint swelling is noted. No long bone deformities or swellings are noted. His pulses and perfusion are good.
Radiographs of his right hip and femur are obtained. No visible fractures are identified. The spaces in the hip joints appear to be symmetric on both sides.
His condition is discussed with an orthopedic surgeon at a tertiary center who agrees to see the patient the next day if his parents are agreeable to this. His parents are informed of the negative radiographs. Other diagnostic possibilities are discussed with them. They prefer to see the orthopedic surgeon tomorrow rather than initiate a partial laboratory work-up in the emergency department.
The next day (two days post injury), he is evaluated by the orthopedic surgeon who notes similar exam findings and reviews the radiographs taken in the emergency department. No radiographic abnormalities are detected by the orthopedic surgeon.
Although there is no history of fever, the patient is sent to the laboratory for a CBC, blood culture, and erythrocyte sedimentation rate. The CBC is unremarkable and the ESR is normal (4 mm/hr).
An ultrasound of the right hip is obtained which fails to demonstrate any joint effusion. A radionuclide bone scan is done which shows no definite focal areas of abnormally increased blood flow. The delayed static bone images show mildly increased tracer localization along the entire length of the femur most likely indicative of a femur fracture. However, the degree of tracer localization is very much less than is typical for a fracture.
At this point, there is no radiographic evidence of a fracture. However, the history indicates that an injury led to the patient’s current symptoms. The radionuclide study is suggestive of a fracture. There is no evidence to support the possibility of transient (toxic) synovitis, any type of acute arthritis, or avascular necrosis of the right hip. There is no laboratory evidence to suggest other inflammatory processes. A repeat set of radiographs is ordered.
The initial set of radiographs (from the rural ED) showed AP and frog views of the pelvis and right femur. The current set of radiographs shown here includes (from left to right) AP, lateral, and oblique views. Only the pertinent parts of the radiographs are displayed in these images. The actual radiographs contained much wider views of the pelvis and the knee. No abnormalities were detected in any of these films.
Another oblique view was taken.
Do you see anything here? A definite fracture is noted on this view. The fracture line is very thin (hairline) and only visible if taken at a very specific angle. The previous six radiographs of the femur failed to demonstrate this.
A large fracture will probably show up on all views of the injured area. Smaller fractures may be visible at certain angles, but usually can be visualized with an AP, lateral, or oblique view. Very small fractures may only be visible at very specific angles such as in this case. Some fractures are not seen easily on plain radiographs.
Radionuclide bone scanning, CT, MRI, or follow-up plain radiographs may be necessary to diagnose such fractures. It should be made clear to patients that a negative set of radiographs does not totally rule out a fracture. This patient received a comprehensive evaluation to investigate the possibility of other orthopedic conditions.
However, from the beginning, his presentation was most consistent with a fracture. In many such instances, clinical suspicion and perseverance are what is necessary to make an occult diagnosis. Give credit to the orthopedic surgeon who persevered in this case.