Last update:
03-Jun-2020

OBJECTIVE To determine the effects of continuous passive motion (CPM), in conjunction with standard physiotherapy, after total knee arthroplasty (TKA), on the active range of motion of the knee and postoperative pain.

METHOD The trial was conducted on 75 patients aged 50–80 years (Clinical Trial Identifier: ISRCTN91125056). The patients were allocated randomly into three groups of 25. The control group followed only the standard in-hospital postoperative physiotherapy intervention. The two study groups followed the physiotherapy intervention, and in addition a 6-day-application of CPM, for 30 minutes twice daily in the first group (CPM-30), and for 60 minutes twice daily in the second group (CPM-60). The range of knee's flexion and extension were recorded preoperative, and post-operative, at the 1st week (post-intervention) and 4th week (follow-up). The post-operative pain levels were evaluated on the 2nd (pre-intervention) and 8th (post-intervention) postoperative days, using the Pain Visual Analogue Scale (VAS).

RESULTS At the 1 week postoperative, only the CPM-60 group had significantly greater flexion by 7.55° (p=0.029) than the control group. At the 4th postoperative week, the degrees of flexion in both intervention groups were statistically higher than in the control group (CPM-30 by 5.42° [p=0.011] and CMP-60 by 13.38° [p<0.001]). The CPM-60 group had a 7.96° greater range of active flexion compared to the CPM-30 group (p<0.001). No difference was observed between the three groups regarding the range of active extension or postoperative pain.

CONCLUSIONS After TKA, the implementation of CPM for 60 minutes twice daily, in addition to the standard physiotherapy intervention, may significantly increase postoperative active knee flexion, but with no effect on knee extension or the pain levels.

Key words: Continuous passive motion, Pain, Physiotherapy, Range of motion, Total knee arthroplasty.