Aluminum levels and stores in patients with total hip endoprostheses from TiAIV or TiAINb alloys.

Aluminum ranks as a potentially hazardous agent. Pathologic findings in different organs show that it can accumulate in brain, muscle, liver and bone. Therefore, we investigated whether patients with cementless total hip endoprostheses made out of titanium alloys containing aluminum are at risk. In order to determine the complete aluminum body loading in patients who have had their hip replacement for a long period of time (mean 58 months), we mobilized possible stores of aluminum with desferoxamine (DFO). Electrothermal atomic absorption spectroscopy was used to quantify the level of aluminum in serum and urine before and after DFO treatment. A serum aluminum value of 10 micrograms/l or less is internationally accepted as safe. The average serum aluminum level in this study was 14.2 micrograms/l, which is slightly above the limit, but clearly below those levels which can lead to disease (> 50 micrograms/l). No relevant storage of aluminum was found. This latter finding is more important since chronically elevated aluminum levels lead to cellular deposits, which affect the cellular biochemistry. The values before and after DFO mobilization did not differ substantially, indicating that aluminum in alloys for biomaterials can be regarded as safe as far as the risk of aluminum release in vivo is concerned. Histologic studies of bone from the bone-metal interface also showed no deposits of local aluminum release.