单髁置换术后膝关节内外侧间室应力变化有限元分析

Finite Element Analysis of Stress of Medial and Lateral Compartments of Knee Joints after Unicompartmental Knee Arthroplasty

目的:采用有限元分析方法研究单髁置换术后膝关节表面应力变化,为深入了解单髁置换术优势及劣势提供依据。方法:对6例单髁置换术后及6例正常人膝关节屈伸活动时关节表面应力变化进行动态有限元分析,并与项目组前期全膝关节置换术后关节表面应力分析进行对比。结果:正常组屈曲30°以后内侧间室应力大于外侧间室(P<0.05);单髁置换组屈曲0°、60°、90°时内侧间室应力大于外侧间室(P<0.05);全膝置换组在所有屈曲角度下内侧间室应力大于外侧间室(P<0.05)。屈曲60°及90°时单髁置换组内侧间室应力大于全膝置换组(P<0.05);所有屈曲角度下,单髁置换组外侧间室应力大于全膝置换组外侧间室应力(P<0.05);屈曲0°、30°、60°及120°时,单髁置换组外侧间室应力都大于正常膝组(P<0.05)。结论:单髁置换术可增加膝关节关节面应力及加速对侧间室关节炎发展,从而影响手术远期疗效,但在严格把握手术适应症、优化手术操作、假体适当改良、指导患者合理康复后,该术式仍具有优势。

Objective To explore stress changes of articular surface of knees after unicompartmentalknee arthroplasty（UKA） using the finite element analysis,so as to make clear the advantages and dis-advantages of such a surgery. Methods Dynamic finite element analysis was performed for 6 patients af-ter UKA and 6 healthy subjects,and compared with previous analysis of patients undergoing total kneearthroplasty（TKA）. Results The stress of medial compartment was significantly bigger than that of thelateral of normal knees when bending to 30°（P〈0.05）. It was the same case for postoperative knees ofTKA in the whole flexion movement and those of UKA at the bending angle of 0°,60° and 90°（P〈0.05 for both）. At the bending angle of 60° and 90°,the stress of the medial compartment of postopera-tive UKA knees was significantly bigger than that of the TKA knees and in the whole flexion move-ment,the stress of the lateral compartment of the former was significantly bigger than the latter,Thestress of lateral compartment of postoperative UKA knees was bigger than the normal controls at thebending angle of 0°,30°,60° and 120°（P〈0.05）. Conclusion UKA may increase the stress of kneejoints and accelerate the development of osteoarthritis of the contralateral compartment,leading to poorlong-term effect. However,the surgery still has advantages if strictly choosing surgery indications,optimiz-ing the surgical operations,properly improving prosthesis and reasonably guiding patients rehabilitation.