Response of human cancellous bone to identically structured commercially pure titanium and cobalt chromium alloy porous-coated cylinders

Abstract

In order to better understand the human cancellous bone ingrowth response into porous coated biomaterials, identically structured commercially pure (CP) titanium and cobalt chromium alloy cylindrical implants were placed into the distal femoral condyles of five human patients. Bone indices (BIs), a measure of bone ingrowth and mineral apposition rates (MARs), were determined for cancellous bone around each implant. The mean BI for CP titanium implants measured 48·4 ± 21·5% while that for cobalt chrome alloy implants measured 26·7 ± 19·7% ( p < 0·05). Mean MARS surrounding CP titanium at 0·92 ± 0–32μ/day were similar to those surrounding cobalt chromium at 0·94 ± 0·39 μm/day ( p > 0·05), however, cancellous bone advanced towards CP titanium and away from cobalt chromium. Based on bone index and the direction of cancellous bone remodeling, the implant model used in this study suggests that there are differences in the response of human cancellous bone to CP titanium and cobalt chromium alloy in porous coated implants.