Youngswick-Austin procedure: the effect of plantar arm orientation on metatarsal head displacement.

The Youngswick-Austin metatarsal head procedure was developed to allow for correction of a mildly elevated metatarsal head and/or to shorten an abnormally long first metatarsal. However, it was difficult to accurately and consistently predict the amount of plantar metatarsal head displacement utilizing this modification of the Austin procedure. This study demonstrated, through the use of preoperative templates and a mathematical formula, that the angle of the plantar arm relative to the weightbearing surface of the foot is what dictates the amount of plantar metatarsal head displacement. The authors divide the angle of the chevron osteotomy into a dorsal and plantar arm angle and demonstrate that the larger the angle of the plantar arm, the greater one can plantarly displace the metatarsal head.