title: A Biomechanical Comparison of Allograft Tendons for Ligament Reconstruction.
abstract: BACKGROUND
  Allograft tendons are frequently used for ligament reconstruction about the knee, but they entail availability and cost challenges. The identification of other tissues that demonstrate equivalent performance to preferred tendons would improve limitations. Hypothesis/Purpose: We compared the biomechanical properties of 4 soft tissue allograft tendons: tibialis anterior (TA), tibialis posterior (TP), peroneus longus (PL), and semitendinosus (ST). We hypothesized that allograft properties would be similar when standardized by the looped diameter.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  This study consisted of 2 arms evaluating large and small looped-diameter grafts: experiment A consisted of TA, TP, and PL tendons (n = 47 each) with larger looped diameters of 9.0 to 9.5 mm, and experiment B consisted of TA, TP, PL, and ST tendons (n = 53 each) with smaller looped diameters of 7.0 to 7.5 mm. Each specimen underwent mechanical testing to measure the modulus of elasticity (E), ultimate tensile force (UTF), maximal elongation at failure, ultimate tensile stress (UTS), and ultimate tensile strain (UTε).
  
  
  RESULTS
  Experiment A: No significant differences were noted among tendons for UTF, maximal elongation at failure, and UTϵ. UTS was significantly higher for the PL (54 MPa) compared with the TA (44 MPa) and TP (43 MPa) tendons. E was significantly higher for the PL (501 MPa) compared with the TP (416 MPa) tendons. Equivalence testing showed that the TP and PL tendon properties were equivalent or superior to those of the TA tendons for all outcomes. Experiment B: All groups exhibited a similar E. UTF was again highest in the PL tendons (2294 N) but was significantly different from only the ST tendons (1915 N). UTϵ was significantly higher for the ST (0.22) compared with the TA (0.19) and TP (0.19) tendons. Equivalence testing showed that the TA, TP, and PL tendon properties were equivalent or superior to those of the ST tendons.
  
  
  CONCLUSIONS
  Compared with TA tendons, TP and PL tendons of a given looped diameter exhibited noninferior initial biomechanical strength and stiffness characteristics. ST tendons were mostly similar to TA tendons but exhibited a significantly higher elongation/UTϵ and smaller cross-sectional area. For smaller looped-diameter grafts, all tissues were noninferior to ST tendons. In contrast to previous findings, PL tendons proved to be equally strong.
  
  
  CONCLUSIONS
  The results of this study should encourage surgeons to use these soft tissue allografts interchangeably, which is important as the number of ligament reconstructions performed with allografts continues to rise.
authors.affiliation: Department of Orthopaedics, University of Maryland, Baltimore, Baltimore, Maryland, USA.
authors.forename: Jeremiah E
authors.initials: JE
authors.lastname: Palmer
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, College Park, Maryland, USA.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Russell
authors.affiliation: Department of Orthopaedics, University of Maryland, Baltimore, Baltimore, Maryland, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Grieshober
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, College Park, Maryland, USA.
authors.forename: Abigail
authors.initials: A
authors.lastname: Iacangelo
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, College Park, Maryland, USA.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Ellison
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, College Park, Maryland, USA.
authors.forename: T Dylan
authors.initials: TD
authors.lastname: Lease
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, College Park, Maryland, USA.
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Orthopaedics, University of Maryland, Baltimore, Baltimore, Maryland, USA.
authors.forename: R Frank
authors.initials: RF
authors.lastname: Henn
authors.affiliation: Department of Orthopaedics, University of Maryland, Baltimore, Baltimore, Maryland, USA.|Fischell Department of Bioengineering, University of Maryland, College Park, College Park, Maryland, USA.
authors.forename: Adam H
authors.initials: AH
authors.lastname: Hsieh
mesh_terms: D064591:Allografts / Q000033:anatomy & histology / Q000502:physiology*; D000070598:Anterior Cruciate Ligament Injuries / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D000070632:Hamstring Tendons / Q000502:physiology / Q000637:transplantation; D006801:Humans; D013710:Tendons / Q000033:anatomy & histology / Q000502:physiology* / Q000637:transplantation*; D013718:Tensile Strength; D014184:Transplantation, Homologous
keywords: allograft tendons; knee ligament reconstruction; peroneus longus; semitendinosus; tibialis anterior; tibialis posterior