Argenson et al. reported 10 years ago on the clinical outcome of 160 unicondylar replacements over 3-10 years in patients who met the relevant surgical indications from July 1989 to March 1997 with a cemented Miller-Galante prosthesis with a metal base. Galante prosthesis with metal base for unicondylar replacement. In the previous study (3-10 years of follow-up), two knees were revised due to wear and replaced with polyethylene liners; three cases had progression of osteoarthritis, two in the lateral tibiofemoral joint and one in the patellofemoral joint. None of the cases underwent revision surgery due to aseptic loosening. The Hospital for Special Surgery knee score (HSS) improved from a preoperative score of 59 to a score of 96. From the results of this score, 147 cases (92%) had excellent outcomes (85-100 points). The average knee flexion was up to 128°. What changes have occurred in the clinical status of this group of patients over the last decade and what is the long-term outcome of unicondylar replacements? To answer these questions, Argenson et al. of the University of Aix-Marseille, France, continued the previous study with a 20-year follow-up, and the results were published in a recent issue of the JBJS. The mean age of this group of patients at the time of initial surgery was 66 years. After an average of 20 years of follow-up, only four patients died and seven were lost to follow-up. 11 patients were revised to total knee replacements, three had patellofemoral replacements, and five had polyethylene liners replaced. Reasons for revision included progression of osteoarthritis in 12 knees, aseptic loosening in 2 knees (no cases of aseptic loosening at 3-10 years of follow-up), and polyethylene wear in 5 knees (liner replaced at an average of 12 years). The clinical and functional scores of the Knee Society Score were 91 and 88, respectively, at the end-of-life follow-up. The mean knee flexion was 127. The authors concluded that in cases of knee osteoarthritis involving only one compartment, the choice of a cemented Miller-Galante prosthesis with a metal base for unicondylar replacement provided sustained pain relief and restored and maintained good knee function without total knee replacement for a long period of time, as shown by the 20-year follow-up results.