Obscure pathology of pulled elbow: dynamic high-resolution ultrasound-assisted classification

Abstract

AimPulled elbow or nursemaid’s elbow is a radial head subluxation caused by a sudden pull on the extended pronated forearm. Children with pulled elbow usually respond dramatically for reduction, yet others show delayed improvement with no clear pathologic explanation. The aim of our study is to propose an explanation for the varying clinical response after the reduction of pulled elbow aided by ultrasound classification of the underlying pathology and its impact on management.Patients and methodsFifty children with a mean age of 3.8 ± 1.1 (standard deviation [SD]) years with pulled elbow were scanned by static and dynamic ultrasound utilizing the other elbow as the standard. The radial annular ligament (RAL) was examined for integrity and interposition, with measurement of the radiocapitellar distance. Reduction was performed following the hyperpronation technique, and postreduction splinting was guided by ultrasound findings. Postreduction scans and 1-year follow up were performed.ResultsOf the 50 included children, 39 (78%) had intact, yet interposed annular ligament (classified as type I) and 11 (22%) had torn annular ligament (classified as type II). The latter underwent splinting for 7 days. Three out of the 50 children had recurrent subluxation and constituted false-negative cases for the detection of torn ligament and represented the reoccurrence rate of 6%. The sensitivity, specificity, and accuracy for the ultrasound diagnosis of torn RAL were 76.9, 92.3, and 92%, respectively.ConclusionPulled elbow is classified as follows: type I, with an interposed RAL, and type II, with torn ligament.