Two- plane point of care ultrasonography helps in the differential diagnosis of pulled elbow

Pulled elbow (PE) is one of the most common injury in children under the age of five years. Diagnosis of PE is usually based on the typical anamnesis and clinical symptoms. A simple reduction maneuver without the need of any imaging modality can eliminate the problem. Certain fractures however can mimic the physical findings of PE and in this cases reduction should not be attempted. The aim of our prospective diagnostic study was to evaluate the accuracy of a sonographic testing method in the differential diagnosis of PE.

205 children aged 0-5 with clinical suspicion for PE were enrolled in our study. Inclusion criteria were the typical clinical sign of PE: painful, motionless, extended or slightly flexed and pronated arm following a traumatic event under the age of five. We excluded older children and patients with pronounced elbow swelling and initially flexed and supinated upper arm position. A two plane point of care sonographic examination was carried out at each patient immediately after history taking and primary physical survey. Presence of the elevated dorsal sonographic fat pad sign(FPS) and the synovial fringe enlargement (SFE) were examined from dorsal and ventral longitudinal planes. Children with FPS positivity and/or unsuccessful reduction were x-rayed. Suspected occult fractures with persistent complains were also x-rayed on the 3rd week. Sonographic pictures and x-rays were analyzed and compared to clinical findings.

The diagnosis of PE was confirmed in 196 cases. (95.6%). 9 children had type I. supracondylar humerus fractures. (4.39%) Out of these 2 proved to be occult fractures.(0.97%). SFE positivity was detected only in the PE group (156 cases, 76%) fractures have not shown this sign. Elevated FPS was negative in all but one PE cases, while all fractures showed FPS positivity without exception. Evaluating the two parameters together both sensitivity, specificity, negative and positive predictive value were 100%.

The two plane sonographic point of care method is an effective tool for confirming the diagnosis of PE and excluding the presence of fractures. It is an easy, standard and objective procedure which can be used as a fast diagnostic test before reduction attempts.