Anterior cruciate ligament reconstruction and the long term incidence of gonarthrosis

Knee ligament injuries are common in sport. A rupture of the anterior cruci ate ligament (ACL) is the most serious of these injuries because it may cau se long term disability. In this literature review, the frequency of post-t raumatic gonarthrosis is examined. There are few long term prospective stud ies but a number of retrospective studies with follow-up times between 5 an d 20 years have been published. These studies show that radiographic gonart hrosis is significantly increased after all knee injuries compared with the uninjured joint of the same patient. Isolated meniscus rupture and subsequ ent repair, or partial or total ruptures of the ACL without major concomita nt injuries, seem to increase the risk 10-fold (15 to 20% incidence of gona rthrosis) compared with an age-matched, uninjured population (1 to 2%). Men iscectomy in a joint with intact ligaments further doubles the risk of gona rthrosis (30 to 40%), and 50 to 70% of patients with complete ACL rupture a nd associated injuries have radiographic changes after 15 to 20 years. Thus , an ACL rupture combined with meniscus rupture or other knee ligament inju ries results in gonarthrosis in most patients. Ten to 20 years after ACL injury, gonarthrosis often presents as a slight j oint space reduction or, occasionally, joint space obliteration (Ahlback gr ades I to II), but is usually not associated with major clinical symptoms. According to the few longitudinal studies, the progress of gonarthrosis is slow, and in some cases the condition seems to remain stable. Time is an im portant determinant for the degree of gonarthrosis and problems demanding t reatment may be encountered only at >30 years after the initial accident.