A novel methodology for the study of injury mechanism: ankle fracture analysis using injury videos posted on YouTube.com.

PURPOSE

An inherent deficiency in the understanding of the biomechanics of fractures is the reliance on cadaveric or other nonphysiological injury models resulting from the prohibitive ethical and practical considerations of conducting injury studies in live participants. We describe a novel methodology for studying injury mechanisms using in vivo injury videos obtained from Youtube.com demonstrating injuries as they occur in real time and correlating them with the resulting injury radiographs.

METHODS

Over 1000 video clips of potential ankle fractures were assessed for clear visualization of the mechanism of injury, including the foot position and deforming force. Candidate videos were selected if the mechanism of injury was classifiable by those described by Lauge-Hansen and there appeared to be a significant mechanism to likely cause fracture. X-rays were then requested from the individuals posting the video clips. Videos and x-rays were reviewed and classified using the Lauge-Hansen system in a blinded manner. The deforming mechanism in the video clips was classified as supination external rotation, supination adduction (SAD), pronation external rotation (PER), or pronation abduction. X-ray fracture patterns were similarly classified.

RESULTS

Two hundred forty videos were selected and individuals posting the videos were contacted. Of 96 initial positive responses, we collected 15 videos with their corresponding radiographs. Eight had SAD-deforming trauma and seven had PER-deforming trauma as appreciated in the videos. There were 12 true ankle fractures. All five fractures judged by video to be SAD injuries resulted in a corresponding SAD pattern radiographic ankle fractures. Of the seven fractures judged by video to be PER injuries, only two resulted in PER pattern radiographic ankle fractures. Five PER injuries resulted in supination external rotation ankle fracture patterns.

CONCLUSION

Our series shows that when in vivo injury videos are matched to their corresponding x-rays, the Lauge-Hansen system is only 58% overall accurate in predicting fracture patterns from deforming injury mechanism as pertaining to SAD and PER injury mechanisms. All SAD injuries correlated but only 29% of PER injuries resulted in a PER fracture pattern. This study illustrates the ethical and practical difficulties of using public access Internet YouTube videos for the study of injury dynamics. The current case series illustrates the method's potential and may lead to future research analyzing the validity of the Lauge-Hansen classification system as applied to in vivo injuries.