Designing of double-threaded intramedullary pin and evaluation of ex vivo biomechanical resistance to axial compression load on the canine long bone fracture gap model

Intramedullary (IM) pinning is a biological method of fracture fixation; but associated with complications ofpin migration, proximal fragment collapse and rotational instability. The study aimed to design double threaded(DT) IM pin evaluated its biomechanical resistance axial compression load in comparison end-threaded(ET) simple Steinman (SS) on the canine long bone gap model. DT was designedconsidering various morphometric measurements (17 femur 8 tibia bones) lateral radiographs routinely done healthy dogs. For ex vivo study, distal third created 17 (8 femoral, 9 tibial) cadaveric bones. A normograde using SS, ET keeping atleast 10 mm at site (fracture gap-model). occupying 60-70% narrowest medullary canal used for ETand DT, >80% SS models. bone-implant constructs were subjected (N) till5 displacement or till dislodgement implant 0.5 mm/min velocity ona servo-hydraulic testing machine. magnitude load/mm influencedby (femur vs tibia) types. In femur, pins sustained higher loads followedby ET. However, tibia, required highest followed by pin. studyreports first kind indigenously designed biomechanically superior threaded longbone fixation