Biomechanical study of the atlantoaxial joint after artificial atlanto-odontoid joint arthroplasty

Abstract

【Abstract】Objective: To investigate the stability and three-dimensional movements of the atlantoaxial joint after artificial atlanto-odontoid joint (AAOJ) arthroplasty by comparing with a conventional method. Methods: After anterior decompression, 24 human ca-daveric spinal specimens of C0-C3 were randomly divided into two groups: Group A receiving artificial AAOJ arthroplasty; Group B experiencing anterior transarticular screw (ATAS) fixation. Two groups underwent flexibility test in intact and instrumented states. Rotational angle of the C0-C3 segments was measured to study the immediate stability and function of anterior decompression with AAOJ arthroplasty compared with the intact state and ATAS fixation. Results: Compared with the intact state, anterior decompression with AAOJ arthroplasty resulted in a sig-nificant decrease in the range of motion (ROM) and neu-tral zone (NZ) during flexion, extension and lateral bending (P<0.05); however, with regard to axial rotation, there was no significant difference in ROM and NZ (P>0.05). Com-pared with anterior decompression with ATAS fixation, an-terior decompression with AAOJ arthroplasty during flexion, extension and lateral bending, significant differ-ence was found in ROM and NZ (P>0.05); however, as for axial rotation, there was a significant increase in ROM and NZ (P<0.05). Conclusion: The self-designed AAOJ has an excellent biomechanical performance, which can restore excellent in-stant stability and preserve the movement of the atlanto-axial joint. Key words: Arthroplasty; Atlanto-axial joint; Bio-mechanics