CEMENT PARTICLES INHIBIT BONE-GROWTH INTO TITANIUM CHAMBERS IMPLANTEDIN THE RABBIT

Particles of bone cement have been shown previously to stimulate the r esorption of bone. The purpose of this study was to determine whether particles of bone cement (BC) have an adverse effect on bone ingrowth. The bone harvest chamber was implanted bilaterally in the proximal ti bial metaphysis of 6 mature rabbits. Both the fixed outer cylinder and the inner removable core of the chamber have a transverse 1 mm wide p ore providing a continuous canal for tissue ingrowth. After an initial 6-week period for osseointegration of the outer cylinder, the content s of the inner core were harvested repeatedly at 3 weekly intervals. I n the first series of rabbits, the carrier solution, 1% sodium hyaluro nate (Healon) was implanted first. In subsequent implantations, Healon was mixed with small fabricated particles of BC (averaging 3.54 mm in diameter) to fill the channel of the core. The contralateral chamber was left empty and served as a control. In the second series of rabbit s, implantation was carried out sequentially using the same material b ilaterally. The sections from the control harvests, and those with Hea lon alone contained extensive trabecular bone arranged longitudinally in the canal, in a fibrovascular stroma. The sections containing BC pa rticles were infiltrated by foamy, mononuclear and multinuclear histio cytic cells. Less trabecular bone was seen in the sections containing BC particles compared to the control sections or those containing Heal on alone. Previous studies have shown that particles of bone cement st imulate bone resorption. In this study, BC particles have also been sh own to diminish the formation of new bone.