Pin removal in slipped capital femoral epiphysis: the unsuitability of titanium devices.

In an effort to predict which slipped capital femoral epiphysis fixation devices might cause fewer retrieval problems, 27 consecutive implant-retrieval procedures were reviewed, and mechanical tests using many currently available devices were performed. Problems occurred with both stainless steel and titanium devices if implanted for > 1 year. This tendency for increased problems was statistically significant for the titanium group, and analysis of a retrieved titanium screw showed evidence of osseointegration (direct bone-metal contact at > 90% of the interface) using backscattered image scanning electron microscopic analysis. These clinical data and data from mechanical testing suggest that stainless steel screws or trocar-tipped Steinmann pins are better suited for fixation of slipped capital femoral epiphysis.