Purpose: To determine the histopathologic changes in coralline hydroxyapatite tricalcium phosphate (HA-TCP) blocks used in the treatment of the postenucleation socket syndrome (PESS).
Methods: Twenty-four patients were treated with HA-TCP blocks placed directly into the orbital fat to correct the PESS. Eight of these patients required partial removal of the material for various reasons between 32 and 371 days after the initial operation. The orbital implants were decalcified and processed for light and electron microscopic examination.
Results: Light microscopy demonstrated fibrovascular ingrowth into the pores of the implant in all cases. Osteogenesis was observed in three cases in the periphery of the implant. Ossification occurred in the implants after a mean implantation duration of 276 days versus 67 days in cases without ossification.
Conclusion: Implants of HA-TCP, a new material used in ophthalmology, demonstrate the presence of fibrovascular ingrowth, reflecting the excellent biointegration of this material.