Ankle and subtalar kinematics during dorsiflexion-plantarflexion activities.
BACKGROUND
Understanding the effect of weightbearing on subtalar and ankle joint kinematics is critical for the diagnosis and treatment of foot disorders. However, dynamic in vivo kinematics of these joints are not well studied. The purpose of this study was to compare in vivo kinematics during nonweightbearing and weightbearing activities in healthy subjects.


METHODS
Seven healthy subjects with a mean age of 32 (range, 23 to 42) years were enrolled. Oblique lateral fluoroscopic images of nonweightbearing and weightbearing dorsiflexion-plantarflexion activities were recorded. Three dimensional subtalar, ankle, and ankle-subtalar joint complex kinematics were determined using 3D-2D model registration techniques with 3D bone models and single-plane fluoroscopy.


RESULTS
During the weightbearing activity from 20 degrees dorsiflexion to 15 degrees plantarflexion, the subtalar joint was significantly more everted, dorsiflexed, and abducted, and the calcaneus showed a significantly more posterior position, than during the nonweightbearing activity. The ankle joint was significantly more plantarflexed and adducted during the weightbearing activity than the nonweightbearing activity. The ankle-subtalar joint complex was significantly more everted, and the calcaneus showed significantly greater posterior position than the nonweightbearing activity.


CONCLUSIONS
These observations provide basic quantitative descriptions of weightbearing and nonweightbearing kinematics for healthy joints.


CONCLUSIONS
These data can serve as the basis for comparison with pathologic feet for both diagnostic and therapeutic purposes.
Yamaguchi
Satoshi
S
Room 330, MAE-A, Gainesville, FL 32611-6250, USA. y-satoshi@mvb.biglobe.ne.jp
Sasho
Takahisa
T
Kato
Hideyuki
H
Kuroyanagi
Yuji
Y
Banks
Scott A
SA
D000328:Adult; D000843:Ankle Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D011403:Pronation / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D013380:Subtalar Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D013484:Supination / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult