[Experimental determination of sliding friction during insertion of femoral intramedullary nails].

No data have published concerning the procedure of driving in intramedullary nails. An extensive experimental device consisting of a contact-free distance measurement, a dynamograph connected to strain gages and an accelerometer now enabled this investigation. Among other things we determined the range of sliding friction for each stroke at different levels of nail-progression. Depending of the depth of nail-progression forces between 200 N und 400 N were measured. When the nail is stuck these values rise to over 1000 N. The sliding-process lasted between 10 ms and 20 ms. Knowledge of these data is of major importance for improvement of surgical technique and possible development of mechanical nail-insertion aids.