• Users Online: 386
  • Home
  • Print this page
  • Email this page
Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 
Year : 2017  |  Volume : 3  |  Issue : 1  |  Page : 45-51

Analysis of strut-to-bone lengthening ratio for hexapod frames using mathematical modeling

1 Texas Scottish Rite Hospital, Dallas, TX, Nemours Children's Hospital, Orlando, FL, USA
2 Department of Orthopedic Surgery, Nationwide Children's Hospital, Columbus, OH, USA

Correspondence Address:
Christopher A Iobst
Department of Orthopedic Surgery, Nationwide Children's Hospital, 700 Children's Drive Suite A2630, Columbus, OH 43205-2696
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jllr.jllr_29_16

Rights and Permissions

Background: Hexapod external fixators often incorporate bone lengthening as part of a multi-planar deformity correction plan. The hexapod struts, however, do not distract in the direction of bone lengthening. Their oblique orientation to the ring creates a vector that is the summation of multiple individual strut adjustments. We demonstrate that a 1 mm lengthening of each of all six struts always created more than 1 mm of lengthening at the bone. Methods: The amount of lengthening was analyzed with the Taylor Spatial Frame™ (Smith and Nephew, Memphis, TN, USA) software using two different methods. Results: As the strut lengths got longer the ratio got closer to one but it never reached 1.0. Conclusions: This information is critical when using very short struts or very large rings. In these two scenarios, the Δ frame height relative to the Δ strut length becomes much greater than one. Clinical Relevance: A strut length much greater than one will cause the bone to lengthen much faster than the surgeon desires. It may also lead to unhealthy regenerate bone formation and could create delays in bone healing.

Print this article     Email this article
 Next article
 Previous article
 Table of Contents

 Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
 Citation Manager
 Access Statistics
 Reader Comments
 Email Alert *
 Add to My List *
 * Requires registration (Free)

 Article Access Statistics
    PDF Downloaded18    
    Comments [Add]    
    Cited by others 1    

Recommend this journal