Introduction: One of the knee's most often injured ligaments is the anterior cruciate ligament (ACL). ACL reconstruction (ACLR) is currently the gold standard of care for elite athletes, with the aim of regaining function and returning to preinjury levels of activity. Although ACLR usually produces good outcomes, second ACL reinjuries are often found, especially in athletes. The aim of the study is to describe the rate of secondary injury in patients following ACLR .
Methods: A comprehensive search for pertinent scientific papers was carried out for this study utilizing a mix of keywords like "reinjury," "secondary injury", "ACLR", and "rate" across several medical databases, including PubMed, Cochrane, and Wiley Online. There were 200 studies found throughout the search from 2019 to 2024. After conducting separate screenings of the abstracts and reference lists and reaching a consensus on any differences, the reviewers included 11 papers.
Results: The electronic search yielded 189 records across multiple databases, with 11 additional records from a registry. After removing duplicates and screening for eligibility, 11 studies were included in the qualitative synthesis, while other studies were excluded for language, differing criteria, or insufficient parameters. This meta-analysis involved 2,620 patients who were athletes from the USA and Europe, aged 15–26, who experienced a first-time ACL injury and underwent ACL reconstruction (ACLR). The stratified analysis revealed a secondary ACL injury rate of 19% (95% CI: 13%-25%). This study showed low heterogeneity (I = 95%, P<0.10). The study found that the secondary ACL injury rate after ACL reconstruction (ACLR) ranged from 13% to 25%, with variation across studies due to differences in patient demographics and reporting methods. Age was a critical factor, with younger patients, especially men under 18, showing higher rates of graft rupture. Contralateral injuries are believed to be influenced by factors like knee alignment and residual deficits, and females may be particularly vulnerable due to rehabilitation-related compensatory mechanisms.
Conclusion: To our knowledge, this is the first study (within the last 5 years) to review the current available literature focusing on secondary injury rates after ACLR. Findings suggest that secondary reinjury rates after ACLR are comparable to previously reported rates. The study highlights that modification in activity, enhanced rehabilitation and return-to-play (RTP) guidelines, and neuromuscular training may help athletes safely return to sports and lower the risk of reinjury.