CONTINUOUS PASSIVE MOTION IN COMPUTER-ASSISTED AUSCULTATION OF THE KNEE

A study of physiological patellofemoral crepitus (PPC) signal recorded from adolescent knees has yielded information which suggests that dec ay time of PPC amplitude due to continuous passive motion (CPM) activi ty is a consistent and useful signature variable for a given knee. The PPC vibrational signal was induced in each case by 1 min of static lo ad on the patella and postural variables during the examination were c arefully controlled. The speed of CPM has been noted as a factor direc tly influencing the rate of PPC amplitude decay; specifically, a highe r CPM speed contributes to an increased decay constant at a cost of in creased inter-subject variability. It is proposed that CPM might form an important basis for the ultimate development of a computer-based au scultation technique for diagnosis of patellofemoral joint disorders.