New Concept for Correction of Brachymetatarsy by 3D CT-Scan Measurement

Abstract

We reported progressive metatarsal lenghtening by external fixator after osteotomy by open approach without bone interposition in a case of brachymetatarsia upon the third and fourth metatarsals. After a tomodensitometry planification, the biometry of the five metatarsal bones was done by X-ray and CT scan by measuring each metatarsal length (1 to 5) in the sagittal, horizontal and coronal plans and angles. The average amount of lengthening was 17 mm for the third and 15 mm the fourth at the end, 40% of the original length (range, 36 to 44%). In the same time, we treated hallux valgus by osteotomy. Decrease of motion and joint deformity did not occur. The control of the CT scan allowed choosing the real orientation and length of the two metatarsal bones to obtain an adequate parabola. Measurements with CT scan were more reliable than Xray.