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Cortical Thickness: A Determinant of Malrotation for Diaphyseal Both Bone Forearm Fractures?

Saturday, October 20, 2012: 9:14 AM
Melrose (Hilton Riverside)
Meredith Osterman, MD1, Joshua M. Abzug, MD2, David Zelouf, MD1, Ross Chafetz3 and A. Lee Osterman, MD1, (1)Orthopaedic Surgery, Thomas Jefferson University Hospital, Philadelphia, PA, (2)Orthopaedic Surgery, University of Maryland, Timonium, MD, (3)Orthopaedic Surgery, Shriners Hospital for Children Philadelphia, Deptford, NJ

Purpose: Malrotation does not remodel and multiple studies have demonstrated a significant loss of rotational motion with treatment of BBFA fractures.  The purpose of this study was to determine if measurement of cortical thickness proximal and distal to the fracture provided the necessary information to determine malrotation.

Methods: Eight cadaveric specimens had an anterior approach to the midshaft of the radius performed, followed by placement of the Multi-Axial Correction system (Biomet).  Subsequently, a transverse osteotomy was performed in the mid-diaphysis of the radius.  Postero-anterior (PA) and lateral fluoroscopic views were obtained after the osteotomy, as well as after rotation of the distal fragment in 10 degree intervals up to 30 degrees.  A direct approach to the ulna was performed and the same procedure was repeated.  All fluoroscopic images were measured to determine the cortical thickness proximal and distal to the osteotomy.  A statistical analysis was performed utilizing Spearman rho correlations to evaluate for a relationship between degrees of rotation and cortical thickness.

Results: Looking at the radius there was no correlation between degree rotation and bilateral distal cortical thickness for the PA views or lateral views.  Similarly, there was no correlation between degree rotation and bilateral proximal cortical thickness for the PA views or lateral views.  Looking at the ulna there was no correlation between degree rotation and bilateral distal cortical thickness for the PA views or lateral views.  Similarly, there was no correlation between degree rotation and bilateral proximal cortical thickness for the PA views or lateral views. 

Conclusion:

Cortical thickness is not a reliable measure of malrotation when assessing BBFA diaphyseal fractures.  Alternative methods, such as intraoperative assessment of passive forearm rotation or images to assess the radial styloid in relation to the biceps tuberosity, should be employed to better assess any component of malrotation.