Review of the all-polyethylene tibial component in total knee arthroplasty. A minimum seven-year follow-up period. A retrospective analysis of 144 total knee arthroplasties was performed between 1975 and 1981 with a minimum follow-up period of seven years. A posterior cruciate condylar prosthesis was used in each procedure. Patients were followed clinically and roentgenographically, and a set of statistical variables was established based on elevation in joint line, tibial component angular alignment, overall limb alignment, and position of the tibial component on anteroposterior and lateral roentgenograms. Review of the study group found that the Hospital for Special Surgery knee scores improved from a preoperative score of 55 to a postoperative score of 88, with 94.5% having good or excellent results. The mean postoperative range of motion was 106 degrees with a mean extension of -0.3 degrees. Radiolucencies developed in 41% of the knees with 5% of the knees having progressive radiolucencies. Eight knees were considered failures based on clinical and roentgenographic evaluations. Factors found to significantly affect the formation of radiolucent lines included a shift of the tibial component medially by greater than 4 mm, a varus tilt of the tibial component greater than 2 degrees, and the diagnosis of rheumatoid arthritis. The only variable associated with aseptic loosening was an elevation of the joint line by greater than 8 mm. 