The biomechanical evaluation of stability and three-dimensional movements for atlanto-axial joint following artificial atlanto-odontoid joint arthroplasty

Abstract

Objective To investigate the biomechanical performance of stability and three-dimensional movements for athmto-axial ioint following artificial atlanto-odontoid ioint arthroplasty.Methods Twelve human cadaveric specimens CO-C4 were loaded nondestructively with 1.53 Nm in the unconstrained testing apparatus.The tested states were intact specimen,after odontoidectomy,posterior transarticular screws,after artificial atlanto-odontoid ioint arthroplasty,and after fatigue test in order.After each state,the range of motion(ROM)at the level of C1,2 Was measured in flexion-extension,lateral bending,and axial rotation direction.Results The angular range of motion and neutral zone during axial rotation at C1-C2 after artificial atlanto-odontoid ioint arthroplasty were proven to get close normal ROM.But there was significant difierence in flexion,extension,lateral bending at C1-C2 as compared with odontoidectomy and intact spine.There were smaller ROM during flexion.extension and lateral bending at C1-C2 after artificial atlanto-odontoid ioint arthroplasty and transarticular screws,but there was significant difference in axial rotation after artificial atlanto-odontoid ioint arthroplasty and transarticular screws.No abrasion and bnormal mobilization were observed after 2000 cycles of flexion,extension,lateral bending and axial rotation in flatigue test.Conclusion The serf-designed artificial atlanto-odontoid ioint arthroplasty Call basically restore excellent stability,and reserve the movement of atlanto-axial ioint instantly after operation. Key words: Biomechanics; Atlanto-odontoid joint; Atlanto-axial joint; Arthroplasty