Biomechanical analysis of a new screwshank metacarpophalangeal joint prosthesis
Objective To study the biomechanical dynamics properties of a new threaded stem metacarpophalangeal joint prosthesis through three-dimensional finite element analysis and to confirm its feasibility for replacement of metacarpophalangeal joints.Methods Using three-dimensional finite element analysis,models for metacarpophalangeal joint replacements with both the new prosthesis and the Swanson prosthesis were developed.The overall stress distribution in the new and Swanson prostheses,the shear force and relative displacement at the contact area between the prosthesis stem and the medullary cavity under different loads,and the stress distribution and changes at the rotational centers of both types of prostheses at various flexion and extension angles were assessed.Results The new threaded stem metacarpophalangeal joint prosthesis exhibited a uniform stress distribution in the structures excluding the joint surface at 0° extension,with a region of increased stress occurring at the joint surface.At 90° flexion,the increase in stress was most notable at the part of the joint surface in contact,resulting in an arc-shaped stress peak.When the prosthesis was dorsiflexed to 50°,stress peaks were observed on the bottom contact surface,indicating a trend of stress values decreasing uniformly from the joint surface towards the prosthesis stem;As the degree of joint flexion-extension movement increased,the stress values at the rotational centers of both prostheses rose,with the highest stress values occurring at 90° of joint flexion.At all measured angles,the stress values at the rotation center of the new threaded stem metacarpophalangeal joint prosthesis were lower than those at the Swanson prosthesis,with the difference being statistically significant(P＜0.05).With a gradual increase in the load applied parallel to the axis of the third metacarpal and directed towards the distal end of the limb at the center of the proximal joint surface,there was a significant in-crease in the shear force at the contact area between the stem of the new threaded stem metacarpophalangeal joint prosthesis and the medullary cavity.Conclusion The biomechanical characteristics of the new prosthesis surpass those of the Swanson prosthesis,and its fixation method is more reliable,which may lead to a longer lifespan in a clinical setting.
Metacarpophalangeal arthritisMetacarpophalangeal prosthesisThree-dimensional finite element analysis
万方数据
维普
