A retrospective comparison of the effect of eMP CS and traditional PS prosthesis on ERAS of total knee arthroplasty

Introduction: The theoretical advantage of medial pivot (MP) knee was thought to justify and replicate the natural knee motion, however, rarely have the comparisons between different designed prosthesis on the enhanced recovery after surgery (ERAS) of TKA can be available. We compared the effect of using Evolution Medial Pivot(eMP) knee system cruciate-substituting (CS) prosthesis and traditional posterior-stabilized(PS) prosthesis on the enhanced recovery after surgery (ERAS) of TKA in order to have a profound understanding of the clinical effects of medial pivot prosthesis. Hypotheses: eMP-CS prostheses can help patients to achieve better recovery after TKA Methods: This study was a retrospective comparison between 2 groups of patients having unilateral TKA(48MP-CS-TKA vs 52 PS-TKA) from Jan 2019 to Mar 2020. The main factors were compared in 2 groups, including Visual Analogue Scale(VAS) pain score,HSS score,FJS-12,range of motion(ROM) and incidence of perioperative complications,as well as overall satisfaction. Results: The VAS score was significantly lower at 1 week,6weeks,3 months and 6 months postoperation than preoperation in two groups(P＜0.05).The HSS score was significant higher at 1 week,,6weeks,3 months and 6 months postoperation than preoperation in two groups (P＜0. 05).The range of motion of knee joint was more than 90° at 1 week after operation in both groups. The recovery of ROM was satisfactory at the early stage,and the ROM increased further with time.There was no statistical difference in VAS,HSS and ROM between two groups in 1 week,6 weeks,3 months and 6 months postoperatively(P＞0.05).In the last follow-up,“Climbing stairs” and “Standing from low sitting position” were the very condition in which the eMP group scored higer.None statistical difference in FJS-12 total score was found between two groups. No significant difference in perioperative complication incidence and blood transfusion rate,and patient-reported satisfaction were observed between two groups(P＞0. 05). Conclusion: Both eMP-CS prostheses and traditional PS prostheses can help to achieve ERAS after TKA.All patients get a satisfying knee function,and the incidence of perioperative complications was low. Nevertheless,it is more natural for eMP-CS prostheses patients to walk stairs and stand up,but no significant difference in patient-reported satisfaction was observed between eMP-CS prostheses and tradional PS prostheses.