Mechanical comparison of application of locking intramedullary nail to locking compression plate in the ovine metatarsus.

Background

The metatarsal bone is commonly utilized in preclinical fracture models in sheep. A majority of studies achieve fracture stabilization with bone plating, but more recently intramedullary interlocking nails (IMN) have been utilized. The mechanical properties of this unique surgical technique utilizing an IMN has not yet been fully elucidated or compared to the traditional locking compression plating (LCP) technique. We hypothesize that a mid-diaphysis metatarsal critical-sized osteotomy stabilized with an IMN will provide equivalent mechanical stability to LCP with less variance of mechanical properties across specimens.

Methods

Sixteen ovine hind limbs were transected at the mid tibia with soft tissue intact and utilized for implantation. A 3-cm osteotomy was created in the mid-diaphysis of all metatarsi. For the IMN group, a 147 mm × 8 mm IMN was implanted from distal to proximal through the sagittal septum of the distal metatarsus and the bolts locked in place using an IMN guide system. For the LCP group, a 3.5-mm 9-hole LCP was secured to the lateral aspect of the metatarsus with three locking screws in the proximal and distal holes leaving the central three holes empty. All metatarsal constructs were fitted with three strain gages on proximal and distal metaphyses and the lateral aspect of the IMN or LCP at the osteotomy site. Non-destructive mechanical testing was performed in compression, torsion, and four-point bending.

Results

The IMN constructs showed overall greater construct stiffness with less variance in strain between constructs than the LCP constructs in 4-point bending, compression, and torsion.

Conclusions

IMN constructs may provide superior mechanical properties for a critical-sized osteotomy model of the ovine metatarsus when compared to lateral LCP constructs. Further

Informations de copyright

2023 Annals of Translational Medicine. All rights reserved.

Déclaration de conflit d'intérêts

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://atm.amegroups.com/article/view/10.21037/atm-22-2746/coif). The authors have no conflicts of interest to declare.