Absence of radiographic abnormalities in nursemaid's elbows

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.

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.

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.

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.

Therapeutic Level III-retrospective comparative study.