A COMPARATIVE BIOMECHANICAL EVALUATION OF A NONCONTACTING PLATE AND CURRENTLY USED DEVICES FOR TIBIAL FIXATION

The appearance of porous bone under fixation plates during fracture he aling, attributed to disturbance of blood supply by the plate, has led to new plate designs with reduced plate to bone contact. The fixation stability afforded by these devices, in comparison to implants common ly used for fixation, is not well known. Therefore, the construct stif fnesses of osteotomized synthetic tibiae fixed with dynamic compressio n plates, external fixators, or two configurations of noncontact plate s were compared in axial compression, bending, and torsion with and wi thout cortical contact at the osteotomy site. The results of this stud y show that (1) the noncontact plated constructs achieve comparable fi xation rigidity to constructs using dynamic compression plates or exte rnal fixators, if applied at a distance no greater than 5 mm from the surface of the tibia, and (2) the fixation rigidity of the noncontact plate decreases as the distance between plate and bone surface increas es.