A Comparison of Results after Anterior Cruciate Ligament Reconstruction in over 40 and under 40 Years of Age: A Meta-Analysis

Anterior cruciate ligament (ACL) injury is one of the most common injuries that occur in the knee, and ACL reconstruction (ACLR) is commonly performed for preventing aggravation of degenerative changes and restoring of knee stability in young, athletic patients. This meta-analysis has a purpose of evaluating the clinical and arthrometrical outcomes of ACLR in a group of middle age patients (40 years and older) and comparing with patients under 40 years of age. MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, and SCOPUS electronic databases were searched for relevant articles comparing the outcomes of ACLR between younger and older than 40 years of age until December 2016. Data searching, extraction, analysis, and quality assessment were performed based on the Cochrane Collaboration guidelines. Clinical outcomes were evaluated and compared between groups. The results were presented as mean difference for continuous outcomes with 95% confidence intervals whereas risk ratio for binary outcomes. Seven studies were included in the meta-analysis. Based on International Knee Documentation Committee classification, side-to-side difference, Tegner activity score, Lysholm knee score, there were no significant clinical and mechanical differences between the groups. This meta-analysis confirmed that after ACLR, middle age (＞40 years) and young age (＜40 years) patients did not present with significant difference in clinical and arthrometric results.