Journal of Postgraduate Medicine
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Year : 1987  |  Volume : 33  |  Issue : 2  |  Page : 77-80  

Mobilization of knee-joint injuries by a continuous passive motion machine.

AB Tillu, PM Kekre, PB Bhonsale, RN Katre 

Correspondence Address:
A B Tillu

How to cite this article:
Tillu A B, Kekre P M, Bhonsale P B, Katre R N. Mobilization of knee-joint injuries by a continuous passive motion machine. J Postgrad Med 1987;33:77-80

How to cite this URL:
Tillu A B, Kekre P M, Bhonsale P B, Katre R N. Mobilization of knee-joint injuries by a continuous passive motion machine. J Postgrad Med [serial online] 1987 [cited 2020 Apr 10 ];33:77-80
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Full Text


In orthopaedics, there is much controversy about whether early mobilization of intra-articular fractures is beneficial or not. Continuous passive motion has been experimentally proved to be helpful for: (a) regeneration of articular cartilage and (b) to get a good range of motion.[1] In our hospital, due to disproportionate ratio of patients to physiotherapists, early mobilization of patients operated upon around the knee joint is a great problem. We, therefore, with the help of an engineer, indigenously developed a continuous passive motion machine (C.P.M.) which is fairly inexpensive as compared to other models available elsewhere. The basic aims of this machine were: (a) early vigourous mobilization of the operated patient with much active supervision of doctors and physiotherapists and (b) aiding regeneration of articular cartilage. We wish to present our experience of using this machine in 13 cases mobilized post-operatively.


Thirteen cases, the details of whom are shown in [Table 1a] and [TABLE 1b], were mobilized post-operatively with the help of a continuous passive motion machine for 3 weeks. Eight cases were of traumatic etiology and the rest 5 had non-traumatic affection of the joint. All the patients were operated upon within one week of their injuries. Initially for the first few days, patients were kept on the C.P.M. machine for two hours (one hour in the morning and one hour in the evening) with prior adjustment of speed and arc of motion. Subsequently, this period was increased to 4 hours per day (1 hour in the morning, 1 hour in the afternoon, 1 hour in the evening and 1 hour at night). In between the session's on the C.P.M. machine, all patients were instructed to strictly adhere to the static quadriceps drill and active mobilization of the affected limb by themselves. Analgesics were given to all patients for an initial period of 4-5 days. Results were recorded at the end of 3, 6 and 12 weeks.


None of our patients required analgesics beyond 4-5 days. All tolerated continuous passive motion well. Initially for the first 2-3 days, patients complained of pain at each session for a period of 5-10 minutes at the beginning but this was bearable. Thereafter, pain gradually diminished. All patients could sleep in the night well without pain. Four patients showed minimal swelling of the foot and leg for the first 2 days. This was treated with elastocrepe bandage. Swelling totally disappeared at the end of the 5th day. [Table 2] shows the range of movements at the knee joint pre-operatively as well as at the end of 3 and 12 weeks. In all traumatic cases, good range of movement (100) was achieved within 8-10 days. For non-traumatic cases, the average period to gain good range of movement was 17 days (range: 12-20 days).

At the end of 3 weeks, all patients had extension lag. But at the end of 6 weeks, only 3 patients had 10 of extension lag. At the end of 12 weeks, none of the traumatic cases had any extension lag but 3 cases of non-traumatic origin had fixed flexion deformity pre-operatively which persisted after operation and mobilization. In all cases, post-operatively, there was a definite increase in the range of motion.


Early mobilization of the joint is very essential to prevent disastrous end results. For this purpose, we attempted to use minimally supervised method of early vigourous mobilization, which aided to a great extent in the post-operative rehabilitation of patients. Besides obtaining a good range of painless motion, we noticed a psychological beneficial effect. Due to painless motion, patient gets confidence to perform early active exercises. This does have a beneficial effect on the ultimate range of motion and muscle power. Salter et al[1] have mentioned the advantage of cartilage regeneration due to C.P.M., but in our study, we could not confirm this through arthroscopy.

The only disadvantage of our machine was that it made a little noise which was disturbing to other patients. The A.C. motor of the machine became hot when used for more than 3-4 hours at a time. This trouble may be eliminated by using a D.C. motor.

We cannot comment on our results as this was our preliminary report on a very small number of patients but we believe that a modified version of this C.P.M. machine has potential to replace a physiotherapist in the post-operative mobilization of the hip and knee joints.


1Sailer, R. B., Simmonds, D. F., Malcolm, B. W., Rumble, E. J., MacMichael, D. and Clements, N. D.: The biological effect of continuous passive motion on the healing of full thickness defect in articular cartilage. An experimental investigation in the rabbit. J. Bone & Joint Surg., 62A: 1232-1251, 1980.

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