Hip Pain in a Hefty 13-Year Old
Radiology Cases in Pediatric Emergency Medicine
Volume 2, Case 12
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
     A 13 year old male was brought to the emergency 
department after injuring his right hip at a soccer game.  
He was running down the field when he heard and felt a 
crack in his right hip.  He was not struck by another 
player.  He did not twist his hip.  He was not kicking at 
the time.  He clearly felt the crack before he fell to the 
ground.  He was unable to get up and since then, he 
has not been able to bear weight on his right leg.  He 
denied any pain in his thigh or knee.  He denied any 
tingling, numbness, or weakness distally.  He had been 
complaining of pain in his right hip for the past two 
weeks, but he did not seek medical attention for this.
     Exam:  T37.0 (tympanic), P100, R20, BP 114/53, 
weight (by history) 105 kg (230 pounds).  He was very 
large for his age of 13 years.  He was moderately 
obese and husky.  He was comfortable lying down.  
Head without signs of trauma.  Neck full range of 
motion.  Heart regular without murmurs.  Lungs clear.  
Chest wall without signs of injury.  Abdomen benign.  
His right hip was very tender on palpation externally.  
Range of motion testing was not performed because 
the patient indicated that this would be very painful.  
There were no visible deformities or bruises.  His thigh 
and knee were not tender.  His neuromuscular function 
below the thigh was normal.  Radiographs of his hips 
were obtained.

View Hip Radiographs.

     His history did not indicate the presence of a 
sudden impact severe enough to cause a fracture 
unless this was a pathological fracture.  His obesity and 
age made the diagnosis of slipped capital femoral 
epiphysis a high likelihood.  In examining his 
radiographs, his femoral physis is nearly fused.  There 
is no difference in the appearance of the right and left 
femoral growth plates.  It does not appear that his 
radiographs are consistent with a slipped capital 
femoral epiphysis.  This was very confusing at the time 
since the clinician was almost certain that the 
radiographs would confirm the diagnosis of slipped 
capital femoral epiphysis.
     An orthopedic consultation was obtained since an 
occult slip of the capital femoral epiphysis was still 
suspected.  The radiographs were interpreted as 
showing an avulsion fracture of the lateral aspect of the 
right acetabulum.  This is visible as a very faint and
indistinct bony fragment (there may actually be two 
fragments) just above the hip joint lateral and superior 
to the superior margin of the acetabulum.  This is so 
faint, you may need to turn down the room lights, adjust 
the contrast on your monitor, and step back to 
appreciate it.

The following radiograph, points it out.

     The black arrows point to the two fracture 
fragments.  If you can't see the black arrows, then you 
need to adjust the contrast on your monitor.
     This fracture probably occurred because of the 
extreme forces borne by the acetabulum.  It is likely 
that his history of hip pain for the previous two weeks 
was the result of weakening of the acetabulum which 
finally resulted in a fracture.
     Since this patient's history and clinical appearance 
was a classic description of a patient with a slipped 
capital femoral epiphysis, this expectation clouded the 
physician's ability to consider an alternative diagnosis.
     The radiographic characteristics of slipped capital 
femoral epiphysis are described in Case 10.
     This case presents a good opportunity to review the 
anatomy of the bony pelvis.  This knowledge is 
important when describing the location of abnormalities 
over the phone when discussing a patient with an 
orthopedic surgeon who is relying on your verbal 
description of the patient's radiographs.
     Identify the labeled structures in the radiograph of 
the pelvis.

View Pelvic Radiograph.

A.  Iliac crest
B.  Sacroiliac joint
C.  Femur head
D.  Acetabulum
E.  Femoral capital physis
F.  Obturator foramen
G.  Pubic symphysis
H.  Lumbosacral junction
I.  Iliac fossa
J.  Pubic ramus
K.  Ischial tuberosity
L.  Femur neck
M.  Greater trochanter
N.  Anterior superior iliac spine

Return to Radiology Cases In Ped Emerg Med Case Selection Page

Return to Univ. Hawaii Dept. Pediatrics Home Page

Web Page Author:
Loren Yamamoto, MD, MPH
Associate Professor of Pediatrics
University of Hawaii John A. Burns School of Medicine