Abstract: Objective To analyse the effect of ultrasound-guided femoral nerve block combined with esketamine on haemodynamics and analgesia in patients undergoing total knee arthroplasty (TKA).Methods A total of 82 patients who underwent TKA in our hospital from March 2024 to February 2025 were selected as the research objects.They were divided into two groups by random number table method,41 cases in each group,and both of them were anesthetized by lumbar-rigid combined anesthesia,the control group was anesthetized by intravenous self-controlled analgesia,and the observation group was anesthetized by ultrasound-guided femoral nerve block combined with esketamine.Recording hemodynamic indexes at baseline before anesthesia (T0),5min after skin cutting (T1),and 2h after the operation (T2);detecting stress indexes at T0,24 h after the operation (T5),and 48h after the operation (T6);and evaluating the patients' pain at rest and in motion using visual analog scoring (VAS) at T2,6h after the operation (T3),12h after the operation (T4),T5,and T6,respectively.and the adverse reactions of the two groups were counted.Results At T1-T2,compared with T0,the mean arterial pressure (MAP),heart rate (HR),diastolic blood pressure (DBP) and systolic blood pressure (SBP) of the two groups decreased,and the differences were statistically significant (P<0.05).The resting state VAS scores at T3,T4,T5 and T6 in the observation group were (1.64±0.39) points,(1.88±0.43) points,(1.73±0.37) points and (1.74±0.46) points,which were significantly lower than those in the control group [(2.74±0.55) points,(2.29±0.58) points,(2.01±0.38) points and (1.84±0.44) points],and the differences between the two groups were statistically significant (P < 0.05).The VAS scores of exercise state at T3,T4,T5 and T6 in the observation group were (2.86±0.76) points,(3.10±0.66) points,(2.43±0.24) points and (2.25±0.23) points,which were significantly lower than those in the control group [(4.65±0.80) points,(5.05±0.54) points,(3.79±0.59) points and (3.15±0.50) points],and the differences between the two groups were statistically significant (P<0.05).At T5 and T6,compared with T0,the indexes of adrenocorticotropic hormone (ACTH),cortisol (Cor),norepinephrine (NA) and epinephrine (AD) in the two groups increased,and the differences were statistically significant (P<0.05).The incidence of postoperative adverse reactions in the observation group (9.76 %) was higher than that in the control group (7.32 %).There was no significant difference between the two groups (P>0.05).Conclusion Ultrasound-guided femoral nerve block combined with esketamine has less impact on hemodynamics and physiological stress in patients undergoing TKA,and has superior analgesic effect,which can promote the recovery of patients' knee joint and quadriceps muscle strength,and has fewer postoperative adverse reactions.

Key words: ultrasound, femoral nerve block, esketamine, total knee arthroplasty, haemodynamics, analgesic effect