Age estimation of living individuals is a regular activity in medico-legal practice. Among the available tools for determining skeletal age, some authors have stated that the disappearance of epiphyseal scars could be a useful marker. The aim of the present study was to assess whether the presence of an epiphyseal scar on the knee, as seen on a plain X-ray, was linked to biological age. A total of 988 frontal X-rays of individuals (509 females and 479 males) aged between 15 and 40 years were analyzed to see whether a scar was visible or not on each of the three epiphyses of the knee. A scar was visible for 96% of the females and 98% of the males. For each sex, scars were visible at each year of age, from 15 to 40 years. In younger females, there were 15 individuals with no scar visible on the fibula, 16 on the tibia, and 20 on the femur. For males, the ages were respectively 16, 17, and 18 years. On a frontal X-ray, the persistence of epiphyseal scars was not a marker of a recent fusion. All individuals with fully ossified knee that had no scar on the femur were older than 18 years. Further studies focusing on epiphyseal scars on MR and CT scans could be useful, as these techniques allow the more precise analysis of the epiphysis.