title: Bi-linear mechanical property determination of acellular human patellar tendon grafts for use in anterior cruciate ligament replacement.
abstract: Anterior cruciate ligament rupture is rising in its prevalence amongst the young and those with physically active lifestyles. Acellular human patellar tendon (PT) grafts offer a promising restoration solution, returning knee joint stability and overcoming some of the current disadvantages of autologous or allogeneic grafts. However, it is necessary to ensure that the decellularisation bio-processes involved do not cause structural changes in the microstructure of the tendon tissue that may adversely affect the mechanical properties, particularly with respect to the physiological range of loading. Sixteen cadaveric human PT grafts were sourced and processed from eight donors, with full ethical approval and consent for use in research. Eight specimens were allocated for decellularisation, while the remaining eight contralateral specimens were used as native controls. Testing consisted of 12 preconditioning cycles followed by uniaxial extension until failure occurred. Stress-strain data was then fitted to a bi-linear model using least squares regression by a custom-written Matlab script. The elastic moduli for the toe region and linear region of each specimen were determined, in addition to the transition point co-ordinates and strain energy density for increasing strain. No significant differences were found between groups for all of the parameters investigated. Hence, the shape and magnitude of the stress-strain profile was found to be the same for both groups throughout loading. The results of this study indicated that decellularisation appeared to have no effect on the material properties of human PT grafts under quasistatic conditions. Therefore, acellular human PT grafts can offer a viable additional solution for ACL replacement compared to current autologous and allogeneic treatment options.
authors.affiliation: (IMBE) Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK. Electronic address: A.Herbert@leeds.ac.uk.
authors.forename: Anthony
authors.initials: A
authors.lastname: Herbert
authors.affiliation: IMBE, Faculty of Biomedical Sciences, University of Leeds, Leeds, UK.
authors.forename: Christopher
authors.initials: C
authors.lastname: Brown
authors.affiliation: NHS Blood & Transplant Services, Speke, Liverpool, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Rooney
authors.affiliation: NHS Blood & Transplant Services, Speke, Liverpool, UK.
authors.forename: John
authors.initials: J
authors.lastname: Kearney
authors.affiliation: IMBE, Faculty of Biomedical Sciences, University of Leeds, Leeds, UK.
authors.forename: Eileen
authors.initials: E
authors.lastname: Ingham
authors.affiliation: (IMBE) Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK.
authors.forename: John
authors.initials: J
authors.lastname: Fisher
mesh_terms: D000368:Aged; D016118:Anterior Cruciate Ligament / Q000502:physiology / Q000601:surgery*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D055595:Mechanical Phenomena; D008875:Middle Aged; D017847:Patellar Ligament / Q000601:surgery*; D019737:Transplants
keywords: ACL replacement; Acellular biological scaffold; Patellar tendon