In vivo skeletal response and biomechanical assessment of two novel polyalkenoate cements following femoral implantation in the female New Zealand White rabbit

Glass-ionomer cements (GIC) offer several advantages over the conventional acrylic-based bone cements. The formation of an adhesive bond with bone and metals, a low setting exotherm and no systemic or local toxicity are some of the advantages cited. This study examines the in vivo biological and bio mechanical behavior of two polyalkenoate cements (LG26 and LG30) implanted for 6 wk into the submetaphyseal spongiosa of the rabbit femur. Cements wer e implanted as both set cement rods and unset cement dough. Implantation of set rods resulted in the formation of variably mineralized osteoid/woven b one at the bone-cement interface. Mechanical (push-out) testing revealed th e strength of this bone-cement interface was of similar magnitude to contro l (PMMA-rod implanted) animals. The bone of LG cement-dough implanted anima ls exhibited demineralization of pre-existing bone local to the site of imp lantation, accumulation of aluminum both locally and at a distance from the site of implantation, and defective mineralization of newly formed osteoid . The histological picture following LG implantation was strikingly similar to human renal osteodystrophy, in which skeletal accumulation of aluminum is a noted feature. The development of a GIC with low/no aluminum release f rom the unset cement dough is a priority in the further development of thes e cements for possible orthopaedic applications. (C) 1998 Kluwer Academic P ublishers.