title: A New Mini-External Fixator for Treating Hallux Valgus: A Preclinical, Biomechanical Study.
abstract: Proximal metatarsal osteotomy is the most effective technique for correcting hallux valgus deformities, especially in metatarsus primus varus. However, these surgeries are technically demanding and prone to complications, such as nonunion, implant failure, and unexpected extension of the osteotomy to the tarsometatarsal joint. In a preclinical study, we evaluated the biomechanical properties of the fixator and compared it with compression screws for treating hallux valgus with a proximal metatarsal osteotomy. Of 18 metatarsal composite bone models proximally osteotomized, 9 were fixed with a headless compression screw and 9 with the mini-external fixator. A dorsal angulation of 10° and displacement of 10 mm were defined as the failure threshold values. Construct stiffness and the amount of interfragmentary angulation were calculated at various load cycles. All screw models failed before completing 1000 load cycles. In the fixator group, only 2 of 9 models (22.2%) failed before 1000 cycles, both between the 600th and 700th load cycles. The stability of fixation differed significantly between the groups (p < .001). The stability provided by the mini-external fixator was superior to that of compression screw fixation. Additional testing of the fixator is indicated.
authors.affiliation: Associate Professor, Department of Orthopaedics and Traumatology, Istanbul Medipol University Medical Faculty, Istanbul, Turkey. Electronic address: drmehmeterdil@gmail.com.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Erdil
authors.affiliation: Orthopedist, Department of Orthopaedics and Traumatology, LNB State Hospital, Istanbul, Turkey.
authors.forename: Hasan Huseyin
authors.initials: HH
authors.lastname: Ceylan
authors.affiliation: Orthopedist, Department of Orthopaedics and Traumatology, Istanbul University Medical Faculty, Istanbul, Turkey.
authors.forename: Gokhan
authors.initials: G
authors.lastname: Polat
authors.affiliation: Medical Doctor, Department of Orthopaedics and Traumatology, Bezmialem Vakif University Medical Faculty, Istanbul, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Kara
authors.affiliation: Faculty, Department of Mechanical Engineering, Istanbul Technical University, Istanbul, Turkey.
authors.forename: Ergun
authors.initials: E
authors.lastname: Bozdag
authors.affiliation: Faculty, Department of Mechanical Engineering, Istanbul Technical University, Istanbul, Turkey.
authors.forename: Emin
authors.initials: E
authors.lastname: Sunbuloglu
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D016267:External Fixators; D006215:Hallux Valgus / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008682:Metatarsal Bones / Q000503:physiopathology / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*
keywords: biomechanical stability; cannulated screw; external fixator; hallux valgus; proximal osteotomy