Finite Element Analysis of Stress of Medial and Lateral Compartments of Knee Joints after Unicompartmental Knee Arthroplasty / 中国运动医学杂志

ABSTRACT

Objective To explore stress changes of articular surface of knees after unicompartmental knee arthroplasty (UKA) using the finite element analysis,so as to make clear the advantages and disadvantages of such a surgery.Methods Dynamic finite element analysis was performed for 6 patients after UKA and 6 healthy subjects,and compared with previous analysis of patients undergoing total knee arthroplasty (TKA).Results The stress of medial compartment was significantly bigger than that of the lateral of normal knees when bending to 30° (P＜0.05).It was the same case for postoperative knees of TKA 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 postoperative UKA knees was significantly bigger than that of the TKA knees and in the whole flexion movement,the stress of the lateral compartment of the former was significantly bigger than the latter,The stress of lateral compartment of postoperative UKA knees was bigger than the normal controls at the bending angle of 0°,30°,60° and 120° (P＜0.05).Conclusion UKA may increase the stress of knee joints and accelerate the development of osteoarthritis of the contralateral compartment,leading to poor long-term effect.However,the surgery still has advantages if strictly choosing surgery indications,optimizing the surgical operations,properly improving prosthesis and reasonably guiding patients rehabilitation.