Winner of the 2008 Systematic Review Competition: Knee Osteoarthritis after Anterior Cruciate Ligament Injury

BACKGROUND: This is a systematic review of studies on the prevalence of osteoarthritis in the tibiofemoral joint more than 10 years after an anterior cruciate ligament injury, the radiologic classification methods used, and risk factors for development of knee osteoarthritis. METHODS: A systematic search was performed in PubMed, EMBASE, and AMED. Inclusion criteria were studies involving patients with anterior cruciate ligament injury, either isolated or combined with medial collateral ligament or meniscal injury and either surgically or nonsurgically treated, and a minimum 10-year follow-up with radiologic assessment. Methodological quality was evaluated using a modified version of the Coleman methodology score. RESULTS: Seven prospective and 24 retrospective studies were included. The mean modified Coleman methodology score was 52 of 90. Reported prevalence of knee osteoarthritis for subjects with isolated anterior cruciate ligament injury was between 0% and 13%. For subjects with anterior cruciate ligament and additional meniscal injury, the prevalence varied between 21% and 48%. Seven different radiologic classification systems were used in the studies. Only 3 studies reported reliability results for the radiologic assessments. The most frequently reported risk factor for development of knee osteoarthritis was meniscal injury. CONCLUSION: This systematic review suggests that the prevalence rates of knee osteoarthritis after anterior cruciate ligament reconstruction reported by previous reviews have been too high. The highest rated studies reported low prevalence of knee osteoarthritis for individuals with isolated anterior cruciate ligament injury (0%-13%) and a higher prevalence of knee osteoarthritis for subjects with combined injuries (21%-48%). Overall, the modified Coleman methodology score was low for the included studies. No universal methodological radiologic classification method exists, making comparisons of the studies and stating firm conclusions on the prevalence of knee osteoarthritis more than 10 years after anterior cruciate ligament injury difficult.