title: Automated fit quantification of tibial nail designs during the insertion using computer three-dimensional modelling.
abstract: Intramedullary nailing is the standard fixation method for displaced diaphyseal fractures of the tibia. An optimal nail design should both facilitate insertion and anatomically fit the bone geometry at its final position in order to reduce the risk of stress fractures and malalignments. Due to the nonexistence of suitable commercial software, we developed a software tool for the automated fit assessment of nail designs. Furthermore, we demonstrated that an optimised nail, which fits better at the final position, is also easier to insert. Three-dimensional models of two nail designs and 20 tibiae were used. The fitting was quantified in terms of surface area, maximum distance, sum of surface areas and sum of maximum distances by which the nail was protruding into the cortex. The software was programmed to insert the nail into the bone model and to quantify the fit at defined increment levels. On average, the misfit during the insertion in terms of the four fitting parameters was smaller for the Expert Tibial Nail Proximal bend (476.3 mm(2), 1.5 mm, 2029.8 mm(2), 6.5 mm) than the Expert Tibial Nail (736.7 mm(2), 2.2 mm, 2491.4 mm(2), 8.0 mm). The differences were statistically significant (p ≤ 0.05). The software could be used by nail implant manufacturers for the purpose of implant design validation.
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.
authors.forename: Jayani P
authors.initials: JP
authors.lastname: Amarathunga
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia Trauma Service, Princess Alexandra Hospital, Brisbane, QLD, Australia.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Schuetz
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia.
authors.forename: Prasad Kvd
authors.initials: PK
authors.lastname: Yarlagadda
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia b.schmutz@qut.edu.au.
authors.forename: Beat
authors.initials: B
authors.lastname: Schmutz
mesh_terms: D000328:Adult; D000368:Aged; D001858:Bone Nails; D003198:Computer Simulation; D019544:Equipment Failure Analysis / Q000379:methods; D005260:Female; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011474:Prosthesis Design / Q000379:methods; D017755:Prosthesis Fitting / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software; D013314:Stress, Mechanical; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013978:Tibial Fractures / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome
keywords: Three-dimensional modelling; automation; fracture fixation; intramedullary nail; nail fit; tibia