Characterisation of the tensile properties of demineralised cortical bone when used as an anterior cruciate ligament allograft

Hexter, Adam T.; Shahbazi, Shirin; Thangarajah, Tanujan; Kalaskar, Deepak; Haddad, Fares S.; Blunn, Gordon

Affiliations

¹Institute of Orthopaedics and Musculoskelatal Science, University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK

²University College Hospital, 235 Euston Rd, Bloomsbury, London, NW1 2BU, UK

³University of Portsmouth, School of Pharmacy and Biomedical Sciences, Portsmouth, PO1 2DT, UK

Abstract and keywords

Background: Graft choice in anterior cruciate ligament (ACL) reconstruction remains controversial and some grafts fail due to inadequate osteointegration. Demineralised cortical bone (DCB) is an osteoinductive collagen-based scaffold. The aim of this study was to measure the tensile properties of DCB from different locations and from different ages, and determine its compatibility with current ACL fixation systems.

Methods: The tensile properties of DCB manufactured from femur and tibia of young (9 month) and old (2–3 years) sheep was measured to determine the most appropriate graft choice. The ultimate load and stiffness of DCB allograft using two fixation systems, interference screws and sutures tied around screw posts, was measured ex vivo in an ovine ACL reconstruction model. Comparison was made with superficial digital flexor tendon (SDFT) and ovine ACL.

Results: DCB derived from young tibia had the highest ultimate load and stiffness of 67.7 ± 10.6 N and 130.2 ± 64.3 N/mm respectively. No DCB fixation system reached the published peak in vivo force through the ovine ACL of 150 N. SDFT fixation with interference screws (308.2 ± 87.3 N) did reach the in vivo threshold but was significantly weaker than ovine ACL (871.0 ± 64.2 N).

Conclusion: The tensile properties of DCB were influenced by the donor age and bone. Owing to inferior tensile properties and incompatibility with suspensory fixation devices, this study indicates DCB is inferior to current tendon grafts options for ACL reconstruction.

Keywords: Anterior cruciate ligament (ACL); Demineralised bone matrix; Demineralised cortical bone; Graft fixation; Tensile properties

Links

DOI: 10.1016/j.jmbbm.2020.103981

PubMed: 32823143

WoS: 000569166000001

History

Received: 2019-10-01

Revised: 2020-01-21

Accepted: 2020-07-08

Online: 2020-07-23

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