BACKGROUND: 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. METHODS: Various conformations of the TSF were made and tested in compression, bending, and torsional loading. RESULTS: 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. CONCLUSIONS: 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.
BACKGROUND: 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. METHODS: Various conformations of the TSF were made and tested in compression, bending, and torsional loading. RESULTS: 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. CONCLUSIONS: 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.