title: Titanium mesh as a low-profile alternative for tension-band augmentation in patella fracture fixation: A biomechanical study.
abstract: OBJECTIVE
  We performed a simple biomechanical study to compare the fixation strength of titanium mesh with traditional tension-band augmentation, which is a standard treatment for transverse patella fractures. We hypothesised that titanium mesh augmentation is not inferior in fixation strength to the standard treatment.
  
  
  METHODS
  Twenty-four synthetic patellae were tested. Twelve were fixed with stainless steel wire and parallel cannulated screws. Twelve were fixed with parallel cannulated screws, augmented with anterior titanium mesh and four screws. A custom test fixture was developed to simulate a knee flexed to 90°. A uniaxial force was applied to the simulated extensor mechanism at this angle. A non-inferiority study design was used to evaluate ultimate force required for failure of each construct as a measure of fixation strength. Stiffness of the bone/implant construct, fracture gap immediately prior to failure, and modes of failure are also reported.
  
  
  RESULTS
  The mean difference in force at failure was -23.0 N (95% CI: -123.6 to 77.6N) between mesh and wire constructs, well within the pre-defined non-inferiority margin of -260 N. Mean stiffness of the mesh and wire constructs were 19.42 N/mm (95% CI: 18.57-20.27 N/mm) and 19.49 N/mm (95% CI: 18.64-20.35 N/mm), respectively. Mean gap distance for the mesh constructs immediately prior to failure was 2.11 mm (95% CI: 1.35-2.88 mm) and 3.87 mm (95% CI: 2.60-5.13 mm) for wire constructs.
  
  
  CONCLUSIONS
  Titanium mesh augmentation is not inferior to tension-band wire augmentation when comparing ultimate force required for failure in this simplified biomechanical model. Results also indicate that stiffness of the two constructs is similar but that the mesh maintains a smaller fracture gap prior to failure. The results of this study indicate that the use of titanium mesh plating augmentation as a low-profile alternative to tension-band wiring for fixation of transverse patella fractures warrants further investigation.
authors.affiliation: Department of Orthopaedics and Rehabilitation, The University of New Mexico Health Sciences Center, MSC10 5600, 1 University of New Mexico, Albuquerque, NM 87131, United States. Electronic address: aaronjdickens@gmail.com.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Dickens
authors.affiliation: Department of Orthopaedics and Rehabilitation, The University of New Mexico Health Sciences Center, MSC10 5600, 1 University of New Mexico, Albuquerque, NM 87131, United States; Center for Biomedical Engineering, The University of New Mexico Health Sciences Center, MSC01 1141, 1 University of New Mexico, Albuquerque, NM 87131, United States.
authors.forename: Christina
authors.initials: C
authors.lastname: Salas
authors.affiliation: Department of Orthopaedics and Rehabilitation, The University of New Mexico Health Sciences Center, MSC10 5600, 1 University of New Mexico, Albuquerque, NM 87131, United States.
authors.forename: LeRoy
authors.initials: L
authors.lastname: Rise
authors.affiliation: Division of Epidemiology, Biostatistics, and Preventive Medicine, Department of Internal Medicine, The University of New Mexico Health Sciences Center, MSC10 5550, 1 University of New Mexico, Albuquerque, NM 87131, United States.
authors.forename: Cristina
authors.initials: C
authors.lastname: Murray-Krezan
authors.affiliation: Department of Orthopaedics and Rehabilitation, The University of New Mexico Health Sciences Center, MSC10 5600, 1 University of New Mexico, Albuquerque, NM 87131, United States; Center for Biomedical Engineering, The University of New Mexico Health Sciences Center, MSC01 1141, 1 University of New Mexico, Albuquerque, NM 87131, United States.
authors.forename: Mahmoud Reda
authors.initials: MR
authors.lastname: Taha
authors.affiliation: Department of Orthopaedics and Rehabilitation, The University of New Mexico Health Sciences Center, MSC10 5600, 1 University of New Mexico, Albuquerque, NM 87131, United States.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: DeCoster
authors.affiliation: Department of Orthopaedics and Rehabilitation, The University of New Mexico Health Sciences Center, MSC10 5600, 1 University of New Mexico, Albuquerque, NM 87131, United States.
authors.forename: Rick J
authors.initials: RJ
authors.lastname: Gehlert
mesh_terms: D001696:Biomechanical Phenomena; D001863:Bone Screws; D001864:Bone Wires; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008953:Models, Anatomic; D010329:Patella / Q000601:surgery*; D016059:Range of Motion, Articular; D013526:Surgical Mesh; D013718:Tensile Strength; D014025:Titanium; D016474:Weight-Bearing
chemical_list: D014025:Titanium
keywords: Biomechanics; Mesh plating; Patella fixation; Patella fracture; Tension band; Titanium mesh; low-profile