A novel osteochondral implant.

A novel implant for the use as an osteochondral graft was designed. This implant was prepared by stepwise formation of calcium phosphate crystals within the matrix of a lyophilised collagen sponge. Chondrocytes were then grown on this material to create the osteochondral implant. The implant was characterized with light microscopy, scanning electron microscopy (SEM), electron diffraction crystallography (EDX), and IR. It was observed with IR that the implant had a peak, that was not found so distinctly in its components, at 1400 cm(-1), implying a strong interaction of the two main ingredients of the implant, calcium phosphate and collagen. This strong interaction was also shown in the graft degradation test while the untreated collagen sponge degraded rapidly (in one day) the mineral loaded implant was able to maintain its integrity for two weeks. In the chondrocyte culture medium degradation of the implant was shown by a decrease of the calcium content and calcium to phosphorous ratio. Also, EDX revealed the presence of sulfur one and two weeks after incubation, an element not found among the components of the implant, possibly due to the development of an extracellular matrix. SEM showed that the form of the crystals of calcium phosphate differed depending on whether they were prepared on the template, collagen, or in the absence of a template. The chondrocytes appeared to be growing in number on the implant and their shapes were morphologically normal. The chondrocyte loaded collagen-calcium phosphate composite could thus be considered a potential tissue engineered osteochondral implant.