FEASIBILITY OF USING A MAGNETIC TRACKING DEVICE FOR MEASURING CARPAL KINEMATICS

While several different methods have been used to measure carpal kinem atics, biplanar radiography is generally considered to be the most acc urate and popular one. However, biplanar radiography is tedious and so only pseudo-dynamic kinematics can be measured. Recently, magnetic tr acking system has been developed for the measurement of joint kinemati cs which is versatile and easy to use and so the possibility of measur ing motions dynamically. In this study, the capability of a magnetic t racking device to accurately measure carpal kinematics was investigate d by comparing it with biplanar radiography. The kinematics of the thi rd metacarpal, scaphoid, and lunate in five fresh cadaveric specimens were measured using both methods as the wrists were placed in eight po sitions. The finite screw rotation of each bone with respect to the di stal radius during selecting the seven wrist motions was calculated fo r both measuring techniques and compared. In general, the kinematics f or all three bones measured by using either magnetic tracking device o r biplanar radiography was identical and showed no statistical differe nce. The averaged differences ranged from 0.0 to 2.0 degrees. These di fferences were due to the potential effect of the weight of the sensor s and the interference of the attaching rod to the surrounding tissue. It is concluded that the application of the magnetic tracking device to carpal kinematics is warranted, if proper technical procedures as s uggested are followed. (C) 1997 Elsevier Science Ltd. All rights reser ved.