Analysis of Finger Joint Kinematics Before and After MCP Joint Arthroplasty

The purpose of this study is to assess the kinematical changes in the flexion of the finger joints after MCP arthroplasty. Angular joint position in relation to its corresponding excursion was used to quantify the kinematics of the finger. The assessment used real time data acquisition and fresh-frozen cadaver hands. Several important benchmarks were considered in analyzing the data. First of all, the initiation of the digit was considered. When a tendon is pulled, motion is normally observed in the DIP first, followed by the PIP, and finally the MCP. This order should be maintained after the arthroplasty. For our kinematics study, it is also important to note any significant increase or decrease in the time of the initiation. Other benchmarks we considered include the starting and ending angle of the joints. The start and ending angle is important when studying the overall range of motion of the digit. The overall range of motion affects basic hand function and is one measure of successful arthroplasty. Excursion was also considered as an overall measure of how well the prosthesis mimics the original joint. Large changes in excursion could indicate that the original center of rotation has not been maintained.