Wide excision of the distal ulna: biomechanical testing of a salvage procedure.

PURPOSE: To study changes in the relationship of the distal radius and ulna after progressive resection of the distal ulna.

METHOD: Six-degree-of-freedom motion sensors were used to determine relative motion and a displacement transducer was used to determine strain changes in the interosseous membrane (IOM). These were applied in cadaveric specimens loaded to simulate wrist motion and axial compressive forces.

RESULTS

Strain in the IOM decreased with increasing resection of the distal ulna. The distance between the radius and ulna decreased with increasing resection up to 20% of ulna length.

CONCLUSIONS

The decreased strain in the IOM and stabilization of the distance between the radius and ulna at 20% resection level provides biomechanical support for the satisfactory clinical results seen after wide ulnar resection. Wide excision of the distal ulna may be a viable salvage alternative to creation of a one-bone forearm.