| 摘要 |
PROBLEM TO BE SOLVED: To provide an osteotomy guide of a thighbone, determining a resection line crossing a distal end of the thighbone in all replacement technique of an artificial knee joint.SOLUTION: An osteotomy guide formed with a slit 151 for guiding a bone saw is installed on a bone surface of a distal end 161 of a thighbone 16. Also, an acceleration sensor 141 capable of respectively measuring three gravity in directions of an X axis and a Y axis perpendicular to each other and a Z-axis directed in a condyle direction at the distal end is installed specifically positioned with the slit. The acceleration sensor is turned internally and externally around a function shaft 162 so as to become three different postures. Two difference vectors are calculated from 3 three-dimensional vectors formed of coordinate values based on the gravity on the X axis, the Y axis and the Z axis. A cross product of the difference vectors is found. The fact that this cross product becomes the rotating shaft in the coordinate system is paid attention, and the coordinate value of the rotating shaft is compared with the coordinate value of the acceleration sensor, and thereby the posture of the acceleration sensor is corrected by an adjusting mechanism so that the rotating shaft becomes parallel to the function shaft. |
