Trabecular Metal Patella Implanted into Soft-Tissue in a Post-Patellectomized Knee A Case Report

Clinical performance and microscopic analysis of a porous tantalum patella, retrieved from a 34-year-old male patient eight months after implantation is reported. The patellar component was sectioned and microscopically analyzed to determine the extent and characteristics of the soft tissue ingrowth. The metallic tantalum represented 20 vol.% of the analyzed patellar component. Large and small spherical pores were identified. Only the large pores had tissue ingrowth, where 92% of the pores were filled with tissue. The interconnected characteristic of the large pores apparently aided the tissue ingrowth. Sixty-four percent of the entire volume had tissue ingrowth. Total ingrowth was to the extent of 80%. From the perspective of tissue ingrowth, the study supports the porous tantalum for clinical applications and warrants continued investigation. This is the first report of which the authors are aware that evaluates the extent of soft tissue ingrowth in a human retrieved trabecular metal patella.