gms | German Medical Science

52. Kongress der Deutschen Gesellschaft für Handchirurgie

Deutsche Gesellschaft für Handchirurgie

06.10. - 08.10.2011, Bonn

A new intramedullary device for distal radius fracture fixation – Biomechanical comparison to volar plating

Meeting Abstract

  • corresponding author presenting/speaker Steven L. Moran - Mayo Clinic, Department of Plastic Surgery, Rochester Minnesota, USA
  • Robert Jan van Kampen
  • Andrew R. Thoreson
  • Nathan J. Knutson
  • Joseph E. Hale

Deutsche Gesellschaft für Handchirurgie. 52. Kongress der Deutschen Gesellschaft für Handchirurgie. Bonn, 06.-08.10.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. Doc11dgh69

DOI: 10.3205/11dgh69, URN: urn:nbn:de:0183-11dgh695

Published: October 5, 2011

© 2011 Moran et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Objective: Intramedullary (IM) devices have been introduced for fixation of distal radius fractures overcoming disadvantages encountered in volar plating, such as extensive periosteal stripping, scarring and tendon irritation. Recent advancements now allow for the placement of an expandable nitinol IM scaffold into the distal metaphysis through the intramedullary canal using percutaneous techniques. We hypothesize that this new IM scaffold performs equivalently to volar plating with respect to stabilization and provides adequate fixation of the fracture during rehabilitation.

Methods: A novel IM scaffold for fixation of distal radius fractures was compared to a commercially available titanium volar locking plate and a stainless steel T-plate (SST). Three different devices were implanted in 18 radius bone surrogates (Sawbones® model 1005). To simulate a dorsally comminuted extra-articular distal radius fracture, a 10-mm dorsal wedge osteotomy was performed. Devices were implanted according to respective instructions for use. For the IM scaffold the canal of the distal metaphysis was prepared, and the scaffold was inserted through a 5-mm diameter drill hole on the lateral aspect of the radius, approximately 7 cm proximal to the fracture site. Cannulated screws were inserted over K-wires placed through the fragments and IM scaffold, providing secure fixation and interfragmentary compression. 10,000 cycles of axial loading of 100 N were applied which simulate unrestricted daily activities during fracture healing. Axial and bending stiffness was assessed before and after cyclic loading, by loading to a maximum of 250N and 75N, respectively. The tested axial and bending loads were selected to exceed maximal physiological loading conditions at the distal radius reported in literature. The data were analyzed using a one-factor ANOVA followed by a Tukey-Kramer post-hoc test, and p-values less than 0.05 were considered significant.

Results: Testing revealed no significant (P=0.956) difference in axial stiffness between the titanium volar locking plate (392±67 N/mm) and the IM scaffold (405±108 N/mm) after 10,000 loading cycles while SST plate stiffness was significantly (P<0.001) less (187±53 N/mm). Bending stiffness was not significantly (P=0.931) different between the IM scaffold (67±140 N/mm) and titanium volar locking plate (63±5 N/mm) while the SST plate bending stiffness was significantly (P<0.001) less (25±4 N/mm).

Conclusion: The novel IM scaffold performed equivalently to a commonly-used titanium volar locking plate and was significantly stiffer than a non-locking stainless steel T-plate, in axial loading and dorsal bending. The IM scaffold provides sufficient fixation of dorsally comminuted distal radius fractures during rehabilitation.