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The in vivo kinematics of the rheumatoid wrist
Author(s) -
Evans James S.,
Blair William F.,
Andrews James G.,
Crowninshield Roy D.
Publication year - 1986
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100040202
Subject(s) - kinematics , wrist , medicine , physical medicine and rehabilitation , geology , computer science , anatomy , physics , classical mechanics
The objectives of this study were (a) to describe the three‐dimensional in vivo kinematic behavior of wrists affected by rheumatoid arthritis, (b) to correlate kinematic parameters and two radiographic indices of carpal disease, and (c) to describe the in vivo kinematic behavior of the Swanson Silastic wrist implant. Fifteen normal wrists, 17 rheumatoid wrists, and 7 wrists with Silastic wrist implants were tested using a three‐dimensional sonic digitizing system. The motion of the hand segment relative to the forearm segment, corresponding to the positions exhibited during flexion‐extension motion (FEM) and radial‐ulnar deviation (RUD), was described using the equivalent screw displacement (ESD) concept. The mean magnitudes of ESD rotation for both FEM and RUD were statistically different (p < 0.05) among the normal, rheumatoid, and implant groups. The remaining ESD parameters (i.e., mean values for the translation, the direction angles of the ESD axis, and the intercepts of this axis with the planes of motion), the minimum separation between the FEM and RUD axes, and the coordinates of the midpoint of this separation were not statistically different (p > 0.05) among the normal, rheumatoid, and implant groups. The two radiographic indices (carpal collapse and carpal translation) did not correlate with the magnitude of rotation or with any other ESD parameter.