步态周期中"8"字绷带外固定对微创治疗拇外翻术后截骨端动态稳定性的有限元分析OACSTPCD

Objective To establish a biomechanical model of plantar-pressure of hallux valgus with minimally invasive technique combined with traditional Chinese and western medicine,and to study the distribution characteristics and biomechanical rules of plantar-pressure mechanical data of"8"shaped bandage external fixation system in dynamic mechanical environment after hallux valgus.Methods Three different angles of the foot were obtained by combining the time phase corresponding to the ground reaction force with the synchronous three-dimensional motion test,and the stress situation of the foot and ankle during the gait cycle after surgery was simulated.Effective constraints and loading were carried out in the finite element model of external fixation of"8"shaped bandage after minimally invasive treatment of hallux valgus.The stress and displacement force of the osteotomy end in each working period during the walking cycle were calculated(heel following the ground period,support period,accelerated push off period),and then the constant changes of the stress of the fixed osteotomy and the displaced end during the surgical gait cycle were explored.Results During the period of mid-heel following the ground,the maximum total stress at the osteotomy end of the first metatarsal bone was 0.118 MPa,following the ground conditions of the midfoot.The first principal stress was located in the Z-axis direction,at-0.116620 MPa.The maximum total displacement of the osteotomy end was 0.447 mm,and the maximum displacement occured on the X-axis,which was-0.446 mm.The displacement direction was opposite to the X-axis,indicating lateral displacement.During the accelerated push off period,the maximum total stress at the osteotomy end was 1.485 MPa;the first principal stress was-1.467620 MPa;the maximum total displacement of the osteotomy end was 1.667 mm;and the maximum displacement occured on the X-axis,which was-1.658 mm.The working condition during the full support period was the same as the direction during the push off period,followed by the numerical value.Conclusion During the gait cycle,the stress on the osteotomy end of the first metatarsal bone is mainly compressive stress,and the displacement is mainly the lateral shift of the distal osteotomy.Postoperative"8"shaped bandage external fixation can ensure the dynamic stability of the osteotomy end after minimally invasive treatment of hallux valgus in the gait cycle,increase the compressive stress of the osteotomy end,and promote the healing of the osteotomy end.