Objective To evaluate the efficacy of phonophoresis of etofenamate gel for postoperative analgesia after total knee arthroplasty (TKA).Methods A total of 80 adult patients were randomly divided into experimental and control groups (n =40 in each group).The same basic analgesia protocol was performed in both groups,while phonophoresis of etofenamate gel was performed only in the experimental group (twice per day,from day 1 to day 7,postoperatively).Data recorded during an 8-week follow-up included Visual Analogue Scale (VAS) scores at rest and during continuous passive motion before surgery and 1 d,3 d,5 d,and 7 d after surgery,range of motion before surgery and 3 d,5 d,7 d,and 8 weeks after surgery,and Hospital for Special Surgery (HSS) scores before surgery and 8 weeks after surgery.SPSS 18.0 was used for statistical analysis.Results The VAS scores at rest and during continuous passive motion 3 d,5 d,and 7 d after surgery were lower in the experimental group than in the control group (P ＜ 0.05).The range of motion 3 d,5 d,7 d,and 8 weeks after surgery was better in the experimental group than in the control group (P ＜ 0.05).The HSS scores 8 weeks after surgery were better in the experimental group than in the control group (P ＜ 0.05).Conclusion Phonophoresis of etofenamate gel provides effective pain control after TKA and is helpful for early functional recovery.