Arthrography is a valuable diagnostic tool in pediatric orthopaedics. Although it is considered safe for systemic use of water-soluble contrast media, toxicities in some tissues have been identified.

The goal of this study is to describe the ultrastructural alterations induced by intra-articular two water soluble contrast media, namely Dimeglumine and Iopromide, in rabbit joint cartilage.

60 rabbit knees were used in this study, 20 receiving 1 ml injections of Dimeglumine, 20 receiving 1 ml injections of Iopromide and the remainder of the knees served as control and injected 1 ml physiological saline. The animals were killed after 1 hour, 1 day, 1 week and 2 weeks and a specimen of the knee cartilage were immersed in to %5 Glutaraldehyde + Phosphate buffer solution and fixed for overnight at +5° C. Tissues were postfixed in %1 Osmium Tetroxide solution for 1 hour and samples were routinely proccessed for electron microscopy.

In the knees injected with SF, the cartilage appeared normal on transmission EM examination and only rare chondrocytes with small glycogen and lipid vacuoles were observed, whereas in those injected with Dimeglumine and Iopromide, increased activation of cells, glycogen and lipid accumulation, collagen fibrils in matrix and especially in those injected with Iopromide decreased matrix around the cells were present in the cartilage. There were very rare picnotic cells in these samples. Contrast agents have local effects as well as systemic effects. In this study detrimental local effects of contrast agents have been demonstrated by high dose exposure in rabbit joint cartilage. We concluded that further work is needed to determine if these effects are of clinical importance.

We have compared the results of simple patellectomy (group A, n = 16) and patellectomy with advancement of the vastus medialis obliquus (group B, n = 12) in a prospective, randomised trial, with a minimum follow-up of three years.

The results in group B were significantly better (p < 0.001) than those in group A. Although the patella should be preserved if possible, we advocate advancement of the vastus medialis obliquus when patellectomy is necessary.