Secondary Logo

Journal Logo

Vannah William M. PhD; Harning, David M. CPO; Hastings, Jeffrey A. MS; Stand, Joseph A.; Drvaric, David M. MD
JPO Journal of Prosthetics and Orthotics: August 21st, 2000
Surface Curvature-Based Modification as a Practical CAD/CAM Rectification for Transtibial Limbs: PDF Only
Free

ABSTRACT

Prosthetic socket digitization creates a quantitative record of the limb shape. From this record, the curvature of the limb's surface at any point can be calculated. The report describes a modification that is based on the limb's surface curvature. Convex areas are relieved and pushed in on, each in proportion to the magnitude of the curvature. Because bony prominences are strong convex shapes (such as the tibial crest), these prominences are relieved. In blinded check-socket testing with 14 subjects, the modification provided a noticeably more comfortable fit (p < .05). The magnitudes of the modifications involved were small; all were <2.0 mm. Although this modification is not a complete rectification, it can provide an improvement in socket fit without cost or other apparent disadvantage. It is necessary to have a quantitative record of the limb shape, such as that available when a computer-aided design/computer-aided manufacturing (CAD/CAM) system is used.

WILLIAM M. VANNAH, directs Biomechanics Research at the Shriners Hospital for Children, Springfield, MA.

DAVID M. HARNING directs the prosthetics department at the Shriners Hospital for Children, Springfield, MA.

JEFFREY A. HASTINGS is a graduate student in engineering at Worcester Polytechnic Institute.

JOSEPH A. STAND is a bioengineer at the Shriners Hospital for Children, Springfield. MA.

DAVID M. DRVARIC is chief of staff at the Shriners Hospital for Children, Springfield, MA.

William M. Vannah, Shriners Hospitals for Children, 516 Carew Street, Springfield; MA 01104. E-mail: wvannah@shrinenet.org

© 2000 American Academy of Orthotists & Prosthetists