Efficacy of plasma-sprayed tricalcium phosphate in enhancing the fixation of smooth titanium intramedullary rods.

The osseous tissue response to intramedullary rods plasma-sprayed with TCP was investigated. TCP-sprayed smooth titanium rods and unsprayed controls were bilaterally implanted into the medullary canals of rabbit tibiae. Rabbits in the short-term study were sacrificed at 3 weeks; rabbits in the long-term study were sacrificed at 12 weeks. Pull-out tests were performed and histological sections prepared. The TCP-sprayed titanium rods exhibited significantly higher pull-out strengths than unsprayed contralateral rods at both 3 and 12 weeks, suggesting the bonding of bone to the TCP layer. The TCP-sprayed titanium rods at 3 weeks showed significantly greater osseous tissue response than unsprayed contralateral controls. At 12 weeks, the osseous tissue response was greater than at 3 weeks, and, surprisingly, the response to TCP-sprayed and unsprayed titanium rods was comparable.