Measurement of forefoot varus angle by laser technology in people with flexible flatfoot.
OBJECTIVE
The purpose of this study was to measure the forefoot varus angles in subjects with and without flexible flatfoot (FF) by using laser foot-scanning technology.


METHODS
In the rehabilitation laboratory of a tertiary medical center, 70 subjects with FF, ranging in age from 10 to 50 yr, were recruited. The control group consisted of 30 volunteers without clinical evidence of FF. A total of 100 positive casts were obtained by having their subtalar joints kept in a neutral position. The plantar surface of the positive cast was scanned by a Yeti 3D Foot Scanner. A straight line was drawn between the first and fifth metatarsophalangeal joints. The forefoot varus angle was measured from this line in relation to the line parallel to the ground.


RESULTS
The mean forefoot varus angle was calculated to be 5.01 +/- 4.51 degrees in our FF subjects, and 1.23 +/- 1.96 degrees in the control group. Significant statistical difference in forefoot varus angle was noted between these two groups.


CONCLUSIONS
The laser foot-scanning technique offers fast and accurate measurement of the forefoot varus angles. An average forefoot varus angle of approximately 5 degrees was observed in subjects with FF, which was significantly greater than the subjects without FF. Therefore, we recommend the concept of incorporating adequate forefoot posting at the medial forefoot area of an insole in treating people with FF.
Chen
Max J L
MJ
Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Tao-Yuan, Taiwan.
Chen
Carl P C
CP
Lew
Henry L
HL
Hsieh
Wei-Chi
WC
Yang
Wen-Pin
WP
Tang
Simon F T
SF
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D002370:Casts, Surgical; D002648:Child; D005413:Flatfoot / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008875:Middle Aged; D008961:Models, Structural; D016474:Weight-Bearing / Q000502:physiology