Abstract:

BACKGROUND: Severe pain after total hip arthroplasty is an important factor for successful rehabilitation of postoperative joint function. Analgesic method after total hip arthroplasty is a hot issue.
OBJECTIVE: To investigate the analgesic effect of different concentrations of ropivacaine after total hip arthroplasty.
METHODS: 69 patients undergoing total hip arthroplasty were recruited from Department of Anesthesiology, Suqian People’s Hospital, from January 2012 to June 2014. According to the ASA classification, their physical status was graded I to III. The involved patients were randomly divided into three groups: 0.25% ropivacaine group, 0.3% ropivacaine group, 0.35% ropivacaine group. Each group had 23 cases. At 30 minutes after the surgery, different concentrations of ropivacaine, 20 mL, were injected to patients due to continuous fascia iliaca compartment block. The catheter was then connected to a patient-controlled analgesia pump programmed to deliver 10 mL with a lockout interval of 60 minutes, for postoperative analgesia (72 hours). At 12, 24, 48 and 72 
hours of blockade, the visual analogous scale (VAS) scores at rest, passive and active activity were recorded. When VAS score at rest ≥ 4 points, parecoxib sodium 40 mg was injected intravenously. The consumption of ropivacaine within 72 hours after the blockade, application of parecoxib sodium, time of ambulation, and adverse reactions during blockade were recorded. The analgesic effect in the three groups was also observed.
RESULTS AND CONCLUSION: Compared with 0.25% ropivacaine group, static VAS scores of 0.3% ropivacaine group and 0.35% ropivacaine group showed no significant difference (P > 0.05), passive and active VAS scores were significantly decreased (P < 0.05), and the consumption of ropivacaine within 72 hours after the blockade was significantly decreased. There was no significant difference in the rest, passive and active VAS scores between 0.3% ropivacaine group and 0.35% ropivacaine group (P > 0.05). The ropivacaine consumption of 0.3% ropivacaine group and 0.35% ropivacaine group was not statistically significant (P > 0.05). The usage of parecoxib sodium in 0.3% ropivacaine group and 0.35% ropivacaine group was significantly lower than that in 0.25% ropivacaine group (P < 0.05). Day of first walk was earlier in the 0.3% ropivacaine group and 0.35% ropivacaine group. The incidence of complications among the three groups showed no significant difference (P > 0.05). Experimental findings indicate that, three different concentrations of ropivacaine has certain analgesic effects after total hip arthroplasty with fewer adverse reactions, and the concentration of 0.3% ropivacaine is the suitable concentration for postoperative analgesia of total hip arthroplasty, it can reduce the amount of parecoxib sodium and shorten the day of first walk.

Key words: Arthroplasty, Replacement, Hip, Nerve Block, Analgesia