The medical records of 319 patients who underwent 350 primary total knee replacements were analyzed retrospectively. The age range was 44-89 years (average 66). In all we used a Biomet ACG prosthesis and preserved the posterior cruciate ligament. Results, measured objectively with Knee Society scores, were satisfactory for all ages, especially the younger. However, even in older age groups subjective results were promising. We emphasize the importance of preserving the posterior cruciate ligament and its advantages for all age groups.