Always struggling with his knees, during the 1960–61 he started to be afflicted by ligament damage. The physios used whatever methods they could to reduce the swellings in his knees, and as he was a big-money signing, Charles would be forced to take to the field week in and week out, despite his injuries.
Throughout the 1960-61 season, Charles struggled with recurring knee issues, which eventually led to ligament damage. The physio team attempted various treatments to reduce swelling, but as a high-profile player, Charles was expected to participate in games regularly, even when injured.