Radiographic and histologic study of porous coated tibial component fixation in cementless total knee arthroplasty.

Radiographic changes occurring beneath three types of non-cemented, porous coated, cobalt-chrome tibial components were retrospectively reviewed a minimum of 1 year after arthroplasty. Radiolucent zones, radiodense lines, and loose sintered particles were commonly observed. These changes are consistent with non-rigid, fibrous tissue fixation. Histologic evaluation of two specimens retrieved at revision surgery revealed predominantly fibrous tissue within the porous surface under the tibial plateau. The long-term implication of fibrous tissue fixation of porous coated tibial implants in unknown.