A method for in-vivo kinematic analysis of the forearm.
OBJECTIVE
To develop a method for in-vivo kinematic study of normal forearm rotation using computed tomographic (CT) images and a custom apparatus which allows for control of amount of forearm rotation.


METHODS
The forearm of one asymptomatic volunteer was CT-scanned in five positions: neutral, 60 degrees pronation, maximal pronation, 60 degrees supination, and maximal supination. Surface registration of the pronated/supinated image datasets with the neutral position was performed. The resulting transformation matrices were decomposed into finite helical axis (FHA) parameters. Kinematics were expressed as motion of the radius relative to the ulna.


RESULTS
The axes of the forearm passed through the volar region of the radial head at the proximal radioulnar joint (PRUJ), extending towards the dorsal region of the ulnar head at the distal radioulnar joint (DRUJ). Distinct FHAs were calculated for each forearm position analyzed relative to neutral rotation. Forearm pronation FHAs were different from forearm supination FHAs.


CONCLUSIONS
Our experimental methodology is capable of describing the in-vivo kinematics of the forearm with good accuracy and reliability. Future in-vivo studies would need to be performed using a larger sample size to further validate our preliminary results. An ideal clinical application of this methodology would be in the comparative study of patients with forearm dysfunction.
Tay
Shian Chao
SC
Orthopaedics Biomechanics Laboratory, Division of Orthopaedic Research, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
van Riet
Roger
R
Kazunari
Tomita
T
Koff
Matthew F
MF
Amrami
Kimberly K
KK
An
Kai-Nan
KN
Berger
Richard A
RA
D000328:Adult; D001696:Biomechanical Phenomena / Q000295:instrumentation / Q000379:methods; D005542:Forearm / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D009068:Movement / Q000502:physiology*; D019047:Phantoms, Imaging; D012399:Rotation; D036542:Tomography, Spiral Computed / Q000379:methods