TY - JOUR
T1 - Pediatric supracondylar humerus fractures
T2 - Effect of bone-implant interface conditions on fracture stability
AU - Lamdan, Ron
AU - Liebergall, Meir
AU - Gefen, Amit
AU - Symanovsky, Naum
AU - Peleg, Eran
PY - 2013/12
Y1 - 2013/12
N2 - Background: Closed reduction and percutaneous fixation with Kirschner wires (KWs) is the standard of care of pediatric supra-condylar humerus fractures (SCHFs). Failure modes leading to loss of reduction are not clear and have not been quantified. Multiple factors may weaken the KW-bone interface bonding conditions. To the best of our knowledge, the possible effect of this decrease on different KW configurations and fracture stability has never been studied. Purpose: To investigate the effect of bone-KW friction conditions on SCHF post-operative mechanical stability and to formulate clinical guidelines for KW configuration under different conditions. Methods: Finite element-based model of a fixated SCHF was used to simulate structure stability for two lateral divergent versus crossed lateral and medial KW configurations under varying KW-bone friction conditions. Results: Finite element simulations demonstrated that crossed KWs provide superior stability compared with the divergent configuration when KW-bone bonding is compromised. When KW-bone bonding conditions are adequate, crossed and divergent KW configurations provide similar, sufficient fracture stability. Conclusions: Under normal bone-implant interface conditions, the two diverging lateral KW configuration offers satisfactory mechanical stability and may be the preferred choice of SCHF fixation. When KW-bone bonding is suboptimal, as when one or more of the lateral KWs are re-drilled, addition of a medial KW should be considered in order to improve stability despite risk to ulnar nerve.
AB - Background: Closed reduction and percutaneous fixation with Kirschner wires (KWs) is the standard of care of pediatric supra-condylar humerus fractures (SCHFs). Failure modes leading to loss of reduction are not clear and have not been quantified. Multiple factors may weaken the KW-bone interface bonding conditions. To the best of our knowledge, the possible effect of this decrease on different KW configurations and fracture stability has never been studied. Purpose: To investigate the effect of bone-KW friction conditions on SCHF post-operative mechanical stability and to formulate clinical guidelines for KW configuration under different conditions. Methods: Finite element-based model of a fixated SCHF was used to simulate structure stability for two lateral divergent versus crossed lateral and medial KW configurations under varying KW-bone friction conditions. Results: Finite element simulations demonstrated that crossed KWs provide superior stability compared with the divergent configuration when KW-bone bonding is compromised. When KW-bone bonding conditions are adequate, crossed and divergent KW configurations provide similar, sufficient fracture stability. Conclusions: Under normal bone-implant interface conditions, the two diverging lateral KW configuration offers satisfactory mechanical stability and may be the preferred choice of SCHF fixation. When KW-bone bonding is suboptimal, as when one or more of the lateral KWs are re-drilled, addition of a medial KW should be considered in order to improve stability despite risk to ulnar nerve.
KW - Finite elements
KW - Kirschner wires
KW - Pediatric
KW - Supra-condylar
UR - http://www.scopus.com/inward/record.url?scp=84890474577&partnerID=8YFLogxK
U2 - 10.1007/s11832-013-0533-4
DO - 10.1007/s11832-013-0533-4
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AN - SCOPUS:84890474577
SN - 1863-2521
VL - 7
SP - 565
EP - 569
JO - Journal of Children's Orthopaedics
JF - Journal of Children's Orthopaedics
IS - 6
ER -