“…Further compounding the problem is the occurrence of subsequent meniscus tears that are reported in the majority of natural history studies [ 8,16,23,26,34,35,49,58,61,78,85,117,120,121,147,160 ] , along with chondral injuries and articular cartilage lesions that presumably result from further giving-way episodes [ 26,35,37,46,49,58,78,92,144,149 ] or increased catabolic activity [ 27 ] . Levy and Meier [ 92 ] reported that the frequency of articular cartilage damage in chronic ACL-de fi cient knees was 79 % overall, with increases from 40 % at 1 year, 60 % at 5 years, and >80 % 10 years following the injury.…”