Effects Of The Second Total Knee Replacement On Early Postoperative Cognitive Function In Elderly Patients

Objective: To investigate the effects of second total knee replacement on early postoperative cognitive function in elderly patients by comparing the changes of postoperative cognitive function and inflammatory cytokines between first and second elective total knee replacement.Methods: 96 ASA II or III patients aged ?60 years undergoing total knee replacement under general anesthesia were enrolled in our study. According to the number of operations they were divided into the first operation group and the second operation group(n=48). Patients were given cognitive function assessment preoperatively and 1d, 3d, 5d, 7d after operation using the Mini-Mental State Examination(MMSE). Postoperative cognitive dysfunction(POCD) was defined by MMSE score decreased ?2 compared with preoperative level. Patients were divided into POCD or non-POCD(NPOCD) group according to the occurrence of POCD. The blood samples were collected before anesthesia induction and 24 h after surgery for detecting the concentrations of IL-1, IL-6, and IL-10 by enzyme-linked immunosorbent assay(ELISA).Results: The incidences of POCD in second group on 3d and 5d postoperatively(56.3% and 10.4%) were significantly higher than those of first group(25.0% and 2.1%)(P< 0.05). Compared with NPOCD group, the concentration of IL-6 at 24 h after operation was significantly higher than its preoperative level and the concentration of IL-10 at 24 h after operation was significantly lower than its preoperative level(P< 0.05) in POCD group. Compared with preoperative level, the concentration of IL-6 was significantly increased and the concentration of IL-10 was significantly decreased(P< 0.05) at 24 h after operation in patients with POCD of two groups. Compared to patients with POCD in the first operation group, the concentration of IL-6 was significantly increased and the concentration of IL-10 was significantly decreased(P< 0.05) at 24 h after surgery in patients of POCD in the second operation group.Conclusion: The incidence of early POCD after the second operation of total knee replacement in elderly patients shows higher than rate after the first operation, which may be related to the concentration of IL-6 increased and the concentration of IL-10 decreased.