Abstract： BACKGROUND: Continuous passive motion assisted with diathermia will promote the restoration of joint movement of the extremities.OBJECTIVE: To improve joint movement with continuous motion assisted with diathermia after surgical treatment on simple fracture of upper or lower extremity.DESIGN: A randomized controlled trial.SETTING: Huaxi Hospital of Sichuan University.PARTICIPANTS: Eighty-four cases of simple extremity fracture treated in the Orthopedic Department of Huaxi Hospital of Sichuan University from October 2000 to July 2002 were included in this trial. Of them, 16 cases were elbow movement disorder and 68 were knee movement disorder. They were randomly assigned into two groups with 42 cases each.METHODS: The 42 cases in the treatment group were preheated before continuous passive motion while those in the control group just received continuous passive motion. The improvement of joint movement between thetwo groups were assessed and compared according to the joint movement scale.MAIN OUTCOME MEASURES: The joint movement before and after treatment and the indices of joint movement scale in the two groups.RESULTS: All of the eighty-four cases entered the analysis. The joint movement in the treatment group was better than that in the control group [ (101.40 ± 25.76)° vs (86.14 ± 27.66)°, t = 5.25, P ＜ 0.01 ]. The index of joint movement scale in the treatment group was also higher than that of the control group[ (84.32 ± 16.54) vs(64. 89 ± 13.76) ] ( t = 4.24, P ＜ 0.01 ) ].CONCLUSION: Continuous passive motion assisted with diathermia is better than simple continuous passive motion in improving the joint movement and function of elbow and knee.