BACKGROUND: Disagreement exists between physicians on the usefulness of a 
prereduction radiograph for diagnosis and treatment of nursemaid's elbows in 
children. Some evidence suggests that nursemaid's elbows have identifying 
features on radiographs. This study compares the radiographs of nursemaid's 
elbows to normal, control elbows in children and hypothesizes that 
differentiating features do not exist on radiograph.
METHODS: For this retrospective case-control study, hospital billing records 
were searched to identify all patients under age 6 treated with closed reduction 
for a nursemaid's elbow between November 2005 and October 2009. Twenty-seven 
nursemaid's elbows were age-matched and sex-matched to 27 normal "comparison 
view," control elbows. Radiocapitellar line offset, proximal radial length, 
anterior fat pad angle, and visibility of the posterior fat pad were measured on 
the radiographs by 2 raters. Their interrater reliability was assessed with 
intraclass correlations, and the nursemaid's and control elbow measures were 
compared using Wilcoxon tests.
RESULTS: Nursemaid's elbows and healthy control elbows did not differ 
significantly in offset of the radiocapitellar line from the capitellum center 
on anteroposterior (P=0.49) or lateral views (P=0.67), in proximal radial length 
(P=0.95), anterior fat pad angle (P=0.49), or posterior fat pad visibility 
(P=1.00) on lateral views.
CONCLUSIONS: Nursemaid's elbows are indistinguishable from healthy elbows on 
radiograph. Thus, the term "radial head subluxation" appears to be a misnomer, 
and prereduction radiographs should only be used to eliminate the possibility of 
fracture. From a radiologic perspective, nursemaid's elbows remain a diagnosis 
of exclusion.
LEVEL OF EVIDENCE: Therapeutic Level III-retrospective comparative study.