Development of an in-vivo method of wrist joint motion analysis.
BACKGROUND
A clinically applicable method of plotting wrist joint motion in three-dimensions has not been described. Computer modelling has been used to improve joint arthroplasty elsewhere in the body. We aimed to develop a method of measuring, and modelling, wrist joint motion that could potentially be used to improve the kinematic performance of wrist arthroplasty designs.


METHODS
An electromagnetic system was used to record wrist motion in three-dimensions. A small pilot study attempted to assess repeatability. A larger group of volunteers with normal wrists was also studied. An iterative computer model, using a two-axis hinge, was developed. One output from this model, the offset of the two axes of motion, is presented as an example of the possible applications of this method of analysis.


RESULTS
For any one individual, in the pilot study, the offset of the axes calculated was relatively reproducible. Between individuals the difference in the offset of the axes was more marked. In 99 normal sets of data the mean axis offset was 6.8mm (range 28 mm to -21 mm) A positive value represented the radio-ulnar deviation axis placed distal to the flexion-extension axis.


CONCLUSIONS
The three-dimensional motion plots generated using this method could be used clinically to follow disease progression or recovery following surgery. The computer modelling method described has potential applications, if further refined, to wrist joint arthroplasty design.
Leonard
L
L
Royal United Hospital, Foxhill, The Old Rope Walk, Tetbury, GLOS GL8 8XQ, Bath, UK. lisa.leonard@virgin.net
Sirkett
D
D
Mullineux
G
G
Giddins
G E B
GE
Miles
A W
AW
D000465:Algorithms; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D008280:Magnetics; D008954:Models, Biological; D009068:Movement / Q000502:physiology*; D010808:Physical Examination / Q000295:instrumentation / Q000379:methods*; D010865:Pilot Projects; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014955:Wrist Joint / Q000033:anatomy & histology / Q000502:physiology*