Any trauma to a joint, even surgery, can potentially start a cascade of events in the joint that lead to cartilage destruction and osteoarthritis. Osteoarthritis has been reported to develop within 10 to 20 years in over half of patients with ACL injuries. However, some research suggests that osteoarthritis is less likely to occur when the torn ACL is reconstructed than when the patient is left with an ACL-deficient knee. If the menisci are intact, fewer than 10 percent of patients have signs of arthritis 10 years after surgery. One recent study found that patients who regained normal knee motion after an ACL injury were less likely to develop arthritis than those who lost knee motion.