Changes in strain distribution along the radius and ulna with loading and interosseous membrane section.

The changes in strain distribution along the radius and ulna with loading and interosseous membrane (IOM) section were analyzed in this biomechanical study. Four cadaveric upper extremities were dissected and strain gauges applied. The forearm was loaded at the distal radius with a carpal implant after being positioned upright in neutral forearm rotation. Strain measurements were recorded before and after transection of the IOM. Before IOM transection, increased compressive strain was measured on the ulnar border of the ulna, while increased tensile strain was recorded on the dorsal aspect of the ulna, the dorsal aspect of the radius, and the lateral border of the radius when compared with the unloaded forearm. This suggests bowing of the radius and ulna with the convex side dorsally and bowing of the radius with the convex side radially. After IOM transection, increased tensile strain on the lateral border of the radius and the ulnar border of the ulna was measured when compared with the loaded forearm with an intact IOM. No change in strain patterns was measured by the strain gauges located on the dorsal aspect of the radius or ulna after IOM transection. The increased tensile strain during constant load application suggests increased bending moments acting on the radius and ulna after IOM transection.