Some patients complain ingrown pain or discomfort after implanting Co-Cr conventional endprosthesis of the hip. Some of this complaint may be attributable for effect on cartilage metabolism. It have been reported that ceramic is bioinert for biological tissue. On the other hand, metal including cobalt-chrome (Co-Cr) have some detrimental effect on biological tissue. However, there is no report concerning acetabular cartilage metabolism after hip endprosthesis implantation. In the present study, we hypothesized that ceramic head have small detrimental effect on cartilage cell metabolism. Specific aim of the study is to compare the protein level of inflammation related cytokines, amount of hyaluronic acid (HA) in culture media, and cartilage mRNA expression in organ culture model of hip end prosthesis implanted using ceramic head and Co-Cr head. Six acetabulum of 3 matured crossbred pig (average weight: 36 +/− 3.6kg) was retrieved. Animal experiment was performed under the rules of ethical committee of animal experiment. Average diameter of pig acetabulum was 26.3 +/− 0.6 mm. Just after sacrifice, mechanical loading using Instron testing machine with 26mm diameter of Co-Cr in right hip and Ceramic heads in left hip was performed in culture media. Ten thousand cycles of cyclic compression and rotation load (1.5kN to 0.15kN of compression and 12 degrees of rotation) to cartilage was applied at 1Hz (Figure 1). Culture media was analyzed for protein levels of inflammation related cytokines and amount of HA. Relative quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) from acetabular cartilage was performed as previously reported using specific primer sets for type II collagen, aggrecan, TNF-alpha, Interleukine-1 and 6, and MMP-1, 3, 13.Introduction
Materials and Methods
