Biomechanical evaluation of two different screw positions for fusion of the calcaneocuboid joint

In triple arthrodesis performed for severe deformity and neuroarthropathy i n poorly compliant patients with osteoporotic bone, fixation of the arthrod esis is critical. We biomechanically tested an alternative means of stabili zation for calcaneocuboid fusions. In seven matched pairs of fresh-frozen c adaver feet, we removed the soft tissue from around the calcaneocuboid join t, except for the capsule, and we did not resect the articular cartilage. O ne joint of each pair was fixed with an oblique standard screw, and the con tralateral joint was stabilized with an axial screw placed perpendicularly to the joint surface. Testing on an MTS Mini Bionix Test Frame (MTS Systems Corp., Eden Prairie, MN) demonstrated that the axial screw provided signif icantly higher initial stiffness and maximum load to failure. We concluded that an axial screw provided better fixation of the calcaneocuboid joint.