title: Osteochondral graft fixation using a bioresorbable bone cement.
abstract: Multiple osteochondral grafts can be used to resurface large joint defects in both humans and horses. In humans, immediate postoperative weight bearing can be prevented, however in the equine, it is unavoidable. Early weight bearing can create detrimental graft micromotion. The aim of this study was to investigate the role of a bioresorbable cement in improving the initial stability of multiple osteochondral graft repairs of large subchondral cystic lesions in the horse. Configurations employed for filling a 20mm diameter cylindrical defect included: (A) twelve 4.5mm diameter grafts with cement, (B) five 6.5mm diameter grafts with cement, (C) four each of 4.5mm and 6.5mm grafts with cement and (D) cement only. Intact bone slices (E) were also tested. Push-out tests were used to quantify construct to host sidewall interface fixation. Configuration (A) proved clinically impractical (n=3). Configurations (B) (n=6), and (C) (n=4) had statistically similar interface stiffnesses and failure stresses (43+/-8 and 30+/-12 MPa and 0.96+/-0.1 and 1.2+/-0.3 Mpa, respectively) suggesting that they are equally susceptible to interface movement in the immediate postoperative period. By way of comparison, defects filled only with cement had an average stiffness of 53+/-7MPa and failure stress of 1.8+/-0.3 MPa (n=6) while the intact femoral condyle demonstrated a stiffness of 108+/-7 MPa and failure stress of 18+/-0.4 MPa (n=6). Cement augmentation improved immediate postoperative stability of multiple osteochondral graft constructs over uncemented constructs, although in all cases the observed moduli of elasticity and yield stress values were lower than those observed for cement only and intact bone test specimens. (all numbers are mean+/-SEM).
authors.affiliation: School of Engineering, University of Guelph, Guelph ON, Canada N1G 2W1.
authors.forename: Adele
authors.initials: A
authors.lastname: Changoor
authors.forename: Mark B
authors.initials: MB
authors.lastname: Hurtig
authors.forename: R
authors.initials: R
authors.lastname: John Runciman
mesh_terms: D020341:Absorbable Implants / Q000592:standards*; D000818:Animals; D001843:Bone Cements / Q000592:standards*; D018786:Bone Substitutes; D002356:Cartilage; D002484:Cementation / Q000592:standards*; D004548:Elasticity; D006736:Horses; D008422:Materials Testing; D016474:Weight-Bearing
chemical_list: D001843:Bone Cements; D018786:Bone Substitutes