Is a Magnetic-Manual Targeting Device an Appealing Alternative for Distal Locking of Tibial Intramedullary Nails?


Department of Trauma Surgery, Medical University of Vienna, Vienna, Austria


In order to enable a radiation-free, accurate and simple positioning of distal locking screws, a combined magnetic and manual targeting system has been developed by Sanatmetal®. Where a low-frequency magnetic field is initially used to detect the position of the first drill hole and three more holes can be found with a mechanical template.

Our cadaver study was performed to evaluate the accuracy and efficiency of this device.

Materials and Methods
In two runs, 30 probands (group 1: 10 students; group 2: 10 residents; group 3: 10 attendings), none of who being familiar with the device, tested the radiation-free system using 60 intact cadaver tibias. Each proband performed the surgical procedure twice in succession.

Referring to the first attempts, 9.6, 7.2 and 7.1 minutes were the time periods required to insert the four distal screws and the relevant values for the second attempts were 8.6, 6.3 and 6.2 minutes; in both cases revealing a significant difference between group 1 and 2 and group 1 and 3. Furthermore, the mean values within each group indicated a significant decrease of the test duration. Out of the 240 drillings, only one failure (group 1) occurred, representing an accuracy of 99.58 %. Of the probands, 90 % rated the targeting device better than the free-hand technique and 77 % at least attested a high user-friendliness.

Due to our satisfactory test results, the brief training, the steep learning curve and the radiation-free technique the new device has to be considered an appealing alternative for distal locking.