Conformational instability of the taylor spatial frame: a case report and biomechanical study.

Abstract

The Taylor spatial frame (TSF) is a second-generation circular fixator used for limb lengthening and deformity correction. While treating a patient for pseudoarthosis, gross instability of a particular TSF construct was observed. A subsequent mechanical study of the TSF was then performed to better understand how its configurations affect frame stability. Various conformations of the TSF were made and tested in compression, bending, and torsional loading. Frame stability was significantly compromised in compression and bending when shorter struts were used and the ring-strut angles were less than 30 degrees. Torsional stability was not significantly affected. Some minor instabilities were noted with an angular ring offset displacement of 25 degrees. Ring-strut angle, a critical factor in truss mechanics, seems to have the greatest influence on stability for the TSF. We recommend that adequate length struts be chosen when constructing a TSF so that ring-strut angles of 30 degrees or less are avoided. Clinical relevance pertains to use of the TSF in atypical conformations, especially in the pediatric population requiring deformity correction.