A Development of Measurement System for Radioulnar Instability by Using 3D Electromagnetic Sensor and Pressure Sensor

Triangular Fibrocartilage Complex (TFCC) improves stability of the wrist joint. TFCC injures occur due to falling, traffic accident, abuse of wrist at work, long-time sport such as tennis, baseball and so on. A method of treatment of TFCC injuries is almost established. However, diagnosis has many points to be improved. There are imaging and palpation for diagnosing TFCC injuries. Imaging can confirm ligament tear; however, it cannot measure bone movement. On the other hand, there are ballottement test, piano key sign, ulnar fovea sign and so on in palpation methods, but these methods largely depend on doctor's sense and experience. Therefore, it is impossible to diagnose quantitatively yet. This study has developed a measurement system to assess instability of ulna toward palmar side and wrist pressure quantitively in real time by using 3D electromagnetic sensor and pressure sensor. Then, this study has measured instability of healthy people. After that, we analyzed a strain of the measurement. In addition, we confirm the repeatability of strain in healthy people.