title: The effect of the addition of hydroxyapatite graft substitutes upon the hoop strain and subsequent subsidence of a femoral model during impaction bone grafting.
abstract: Impaction bone grafting using morcellised allograft can successfully restore bone stock in revision surgery. However, concerns exist regarding supply of bone and transmission of infection. Bone-graft extenders, such as tricalcium phosphate (TCP) and hydroxyapatite (HA), are used to minimise the use of donor bone. However, concerns exist around a reported increased risk of femoral fracture during impaction bone grafting with a 1:1 mixture of TCP/HA and morcellised bone graft (MBG) during impaction grafting in human cadaveric femora. Using a sawbones model, it was evaluated whether there was increased femoral cortical strain with a HA:MBG mixture during impaction grafting compared to MBG impacted at the same and a greater force. Subsequently the subsidence behaviour of the different graft mixes was compared by using a loaded femoral stem in an endurance test. It was demonstrated that the femora with the MBG:HA graft had greater cortical hoop stresses but improved subsidence behaviour compared to a graft composed of pure MBG impacted at the same force.
authors.affiliation: Orthopaedic Research Unit, Addenbrooke's Hospital, Cambridge, CB1 1QQ, United Kingdom. imcnamara@doctors.org.uk
authors.forename: I R
authors.initials: IR
authors.lastname: McNamara
authors.forename: A
authors.initials: A
authors.lastname: Rayment
authors.forename: R
authors.initials: R
authors.lastname: Brooks
authors.forename: S
authors.initials: S
authors.lastname: Best
authors.forename: N
authors.initials: N
authors.lastname: Rushton
mesh_terms: D016025:Bone Transplantation / Q000379:methods*; D002130:Calcium Phosphates / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry*; D004548:Elasticity; D005269:Femur / Q000601:surgery*; D006801:Humans; D008422:Materials Testing; D013314:Stress, Mechanical; D014783:Viscosity
chemical_list: D002130:Calcium Phosphates; D017886:Durapatite; C018392:tricalcium phosphate