[Feedback-controlled weight bearing following osteosynthesis of the lower extremity]

Truly partial weight bearing by usual mode of mobilisation after an operation of the lower limb is not a realistic goal. Frequent and massive overloading could recently be shown in a series of patients with joint replacements. Significant improvements in the loading pattern could be demonstrated with the use of an acoustic feedback system. Our goal was to test the clinical application of this method by using a similar system in the form of an insole-installed device. In the same trial, data on the real weight bearing pattern with prescribed loading after osteosyntheses was to be collected with and without the feedback device. We measured weight bearing continuously in two groups of patients. The first group was mobilised in the usual manner whereas the second group was acoustically alerted to overloading when passing the limit of 15 kg by a sensor device in the insole. Our results showed that 40.8% of steps made by patients mobilised in the usual manner were massively overloaded whereas 12.7% of steps in the second feedback-group produced even minor overloading. Apart from certain technical difficulties, the method was well accepted by the patients. The usual method of progressive weight bearing is unreliable. The value of partial weight bearing after internal fixation of the lower limb remains to be evaluated. In cases in which partial weight bearing is recommended, more attention should be paid to observing the prescribed limits and a reliable system that alerts the patient of excessive weight bearing would be most useful. For routine use in clinics a technically more reliable PMT Feedback System has to be developed.