Survivorship of cementless total knee arthroplasty without tibial plateau screw fixation.

Seventy-two cementless tricompartmental total knee arthroplasties were performed in 47 patients using a porous-coated prosthesis without screw fixation for the tibial components between 1984 and 1986. These individuals were observed at regular intervals for a minimum of three years. Their Hospital for Special Surgery pain and function scores as well as roentgenographic signs of anatomic alignment and subsidence were evaluated at six months, one year, and three years postoperatively. The roentgenographic evaluation for subsidence looked at a measurable difference in the anteroposterior roentgenograph on the medial and lateral plateaus and on the lateral roentgenograph anteriorly and posteriorly. Early postoperative interpretations have suggested pain and knee scores to be much lower than scores in the cemented prosthesis. Reassessment after three years, however, revealed no further deterioration of the noncemented prosthesis in respect to knee scores and survival analysis. Roentgenographic analysis showed no correlation between subsidence and alignment alterations, subsidence and time, or subsidence and pain. It appears that after an initial period of discomfort, the noncemented knee can achieve a functional, clinical, and roentgenographic result much better than previously anticipated. The consequences beyond this time period still remain unknown.