Devices for continuous passive motion, also known as motor-driven splints, are widely used in rehabilitation therapy following injuries and surgery. They present an adjunct method substituting the physical work of a physiotherapist. The method is indicated in early post-injury or post-operative periods. It is expected to increase blood drainage and remove haemarthrosis and synovial fluid exudate which precede an undesired development of granulation and fibrous tissues. However, continuing such an intensive therapy after 3 to 4 post-operative weeks lacks its raison d'être. The only exceptions include conditions after autologous chondrocyte transplantation and a supplementary therapy to active rehabilitation programmes for releasing muscle hypertonia which restricts movement. Values for the range of motion set up on the device cannot be considered the real values pertinent to the exercised joint; these are usually considerably lower. Key words: continuous passive motion, motor-driven splint.