Chondral injuries to the knee joint refer to damage that’s done to the articular cartilage on the ends of the bones that make up the knee, the femur and tibia, but can also occur on the back side of the patella (kneecap). Chondral injuries are common to the knee joint especially with ACL injuries or multi-ligament injuries. One study reported 23% of acute ACL injuries and 54% of chronic ACL knees had articular cartilage damage.