Fixation of a hydroxyapatite-tricalcium phosphate-coated cementless knee prosthesis. Clinical and radiographic evaluation seven years after surgery.

Miller-Galante II total knee arthroplasty (MG II TKA) was performed on 32 knees in 30 patients. On both the femoral and tibial components, the fibre-metal area was plasma-sprayed with hydroxyapatite-tricalcium phosphate (HA-TCP). The clinical and radiographic outcome was evaluated. A mean preoperative knee score of 26.0 +/- 18.6 (SD) increased to 97.5 +/- 3.5 and a mean pre-operative functional score of 21.7 +/- 15.0 (SD) increased to 83.4 +/- 12.4 at follow-up of seven years. Clear zones were common around the components at one month post-operatively but had completely disappeared after six months. An autopsy of a patient who underwent MG II TKA with HA-TCP two years previously, showed osteogenesis in all parts of the fibre-metal, and bone tissue comprised 77.7% of the interface. This coated prosthesis has good early fixation which is maintained at seven years with good clinical and radiographic outcomes.