Session VII - Foot / Ankle

Sat., 10/12/13 Foot/Ankle, PAPER #79, 10:29 am OTA 2013

Does the Müller AO Classification System for Ankle Fractures Correlate More Closely to the Mechanism of Injury Than the Lauge-Hansen System?

Edward K. Rodriguez, MD, PhD1; John Y. Kwon, MD2; Lindsay M. Herder, BA1; Paul T. Appleton, MD1;
1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
2Massachusetts General Hospital, Boston, Massachusetts, USA

Purpose: This study was conducted to assess whether the Lauge-Hansen (LH) and the Müller AO classification systems for ankle fractures radiographically correlate consistently with real in vivo injuries as based on observed mechanism of injury.

Methods: Videos of potential study candidates sustaining ankle injuries were reviewed on YouTube.com and individuals were recruited for participation if the video was of sufficient quality to classify the injury mechanism and if the individual demonstrated sufficient trauma likely to have sustained an ankle fracture. Corresponding injury radiographs were obtained. Injury mechanism seen in the video clips was classified using the LH system as supination/external rotation (SER), supination/adduction (SAD), pronation/external rotation (PER), or pronation/abduction (PAB). Corresponding radiographs were classified by the LH system and the AO system.

Results: Of over 2500 video clips reviewed, 625 demonstrated an injury mechanism classifiable by the LH system with a likelihood of sustaining an ankle fracture and were invited to participate. Of the 116 responders, 30 injury videos with their corresponding radiographs were collected. Of the video clips reviewed, 16 had SAD deforming trauma and 14 had PER deforming trauma. There were 26 ankle fractures, 3 nonfractures and 1 subtalar dislocation. 12 fractures judged by video to be SAD injuries had corresponding SAD fracture patterns. Five PER video injuries had PER fracture patterns. Eight PER video injuries resulted in SER fracture patterns and one resulted in a SAD fracture pattern. When using the AO classification, all 12 SAD type injuries that resulted in a fracture resulted in 44A type fractures while the 14 PER injuries resulted in nine 44B fractures, two 44C fractures, and three 43A fractures.

Conclusion: When in vivo video injury clips of ankle fractures are matched to their corresponding radiographs, the LH system is 65% consistent in predicting fracture patterns from deforming injury mechanism. When using the AO classification system, overall consistency was 81%, as a PER mechanism appears to mostly result in 44B type fractures. The AO classification, despite its development as a purely radiographic system, appears to correlate with in vivo injuries more consistently than the LH system.

Alphabetical Disclosure Listing

• The FDA has not cleared this drug and/or medical device for the use described in this presentation   (i.e., the drug or medical device is being discussed for an “off label” use).  ◆FDA information not available at time of printing. Δ OTA Grant.