title: The efficacy of cylindrical titanium mesh cage for the reconstruction of a critical-size canine segmental femoral diaphyseal defect.
abstract: The authors developed a novel technique for the reconstruction of large segmental long bone defects using a cylindrical titanium mesh cage (CTMC). Although the initial clinical reports have been favorable, the CTMC technique has yet to be validated in a clinically relevant large animal model, which is the purpose of this study. Under general anesthesia, a unilateral, 3-cm mid-diaphyseal segmental defect was created in the femur of an adult canine. The defect reconstruction technique consisted of a CTMC that was packed and surrounded with a standard volume of morselized canine cancellous allograft and canine demineralized bone matrix. The limb was stabilized with a reamed titanium intramedullary nail. Animals were distributed into four experimental groups: in Groups A, B, and C (six dogs each), defects were CTMC reconstructed, and the animals euthanized at 6, 12, and 18 weeks, respectively; in Group D (three dogs), the same defect reconstruction was performed but without a CTMC, and the animals were euthanized at 18 weeks. The femurs were harvested and analyzed by gross inspection, plain radiography, computed tomography (CT), and single photon emission computed tomography (SPECT). The femurs were mechanically tested in axial torsion to failure; two randomly selected defect femurs from each group were analyzed histologically. Groups A, B, and C specimens gross inspection, plain radiography, and CT, demonstrated bony restoration of the defect, and SPECT confirmed sustained biological activity throughout the CTMC. Compared to the contralateral femur, the 6-, 12-, and 18-week mean defect torsional stiffness was 44.4, 45.7, and 72.5%, respectively; the mean torsional strength was 51.0, 73.6, and 83.4%, respectively. Histology documented new bone formation spanning the defect. Conversely, Group D specimens (without CTMC) demonstrated no meaningful bone formation, biologic activity, or mechanical integrity at 18 weeks. The CTMC technique facilitated healing of a canine femur segmental defect model, while the same technique without a cage did not. The CTMC technique may be a viable alternative for the treatment of segmental long bone defects.
authors.affiliation: Department of Orthopaedic Surgery, Baylor College of Medicine, 6560 Fannin, Suite 1900, Houston, Texas 77030, USA. rwlindsey@utmb.edu
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Lindsey
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Gugala
authors.forename: Edward
authors.initials: E
authors.lastname: Milne
authors.forename: Michael
authors.initials: M
authors.lastname: Sun
authors.forename: Francis H
authors.initials: FH
authors.lastname: Gannon
authors.forename: Loren L
authors.initials: LL
authors.lastname: Latta
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001852:Bone Lengthening / Q000295:instrumentation*; D018483:Diaphyses / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D004285:Dogs; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016268:Internal Fixators; D016348:Osseointegration / Q000502:physiology; D013526:Surgical Mesh; D013669:Technetium Tc 99m Medronate; D014025:Titanium; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
chemical_list: D014025:Titanium; D013669:Technetium Tc 99m Medronate