Total knee arthroplasty using an uncemented, polyethylene tibial implant. A seven-year follow-up study

A seven-year postoperative evaluation of 54 patients with either osteoarthrosis or rheumatoid arthritis was conducted. Uncemented, posterior cruciate-retaining, pegged tibial implants produced clinical and roentgenographic results comparable to those seen with standard cemented total knee arthroplasty (TKA). Subsidence, however, seemed to be slightly increased in the uncemented group especially if there was incomplete coverage of the tibial plateau surface. The mere presence of subsidence was not correlated with any increase in pain, although the four implant failures in which the patients had painful loose prostheses all had some subsidence. The cumulative survival rate at seven years was 92.3%, with four arthroplasty failures. Roentgenographic appearance of condensation about the pegs was not statistically correlated with the presence or absence of pain or subsidence. The roentgenographic appearance of opacification in the declivities of the undersurface of the component, however, was associated with a statistically significant decrease in the incidence of subsidence.