A Comparison of Bicortical and Intramedullary Screw Fixations in Jones' Fractures Using Finite Element Analysis: Preliminary Report / 대한스포츠의학회지

ABSTRACT

Intramedullary screw fixation and bicortical screw fixation are widely used operation methods in the surgical treatment of Jones fractures. The purpose of this study is to evaluate of mechnical stability in two kind of Jones fracture. Using Mimics, three-dimensional models of the fifth metatarsal were reconstructed form computed tomography images of a 23-year-old Korean healthy male. Normal and osteoporotic bone models were made by changing bone density or thickness of cortical and cancellous bone. Two kinds of fixation techniques, i.e., intramedullary and bicortical screw fixation models, were simulated and muscles forces related to the fifth metatarsal base were applied. Maximum contact pressure difference were measured as 20,818 MPa, 12,155 MPa in normal bone, 23,371 MPa, 13,765 MPa in 85% cancellous osteoporotic bone, 24,310 MPa and 14,264 MPa in 75% cancellos osteoporotic model, 21,337 MPa, 20,971 MPa in -0.5 mm cortical osteoporotic bone, 26,322 MPa and 36,153 MPa in -1 mm cortical osteoporotic model, respectively for intramedullary screw fixation and bicortical screw fixation. Displacements on fracture interface were 0.208 mm, 0.126 mm in normal bone while 0.229 mm, 0.127 mm in 85% cancellos osteoporotic model, 0.241 mm, 0.127 mm in 75% cancellos osteoporotic model, 0.223 mm, 0.271 mm in -0.5 mm cortical osteoporotic model, 0.292 mm, 0.480 mm in -1 mm cortical osteoporotic model, respectively for intramedullary screw fixation and bicortical screw fixation. Bicortical screw fixation is superior in mechanical stability than intramedullary screw fixation for normal bone quality Jones fractures. For cortical osteoporotic bone Jones fractures, however, intramedullary screw fixation can give a better mechanical stability than bicortical screw fixation.