Introduction: The incidence of Anterior cruciate ligament (ACL) injury continues to increase each year. Many tools have been developed and validated to specifically measure function after an ACL injury. However, variability in these tools makes it difficult to compare and pool the results across different studies, potentially impacting on the quality of the evidence available to patients, clinicians, and policy makers. The aim of this scoping review was to summarize the different functional outcome measures and study characteristics in longitudinal studies of people following ACL injury.
Methods: Four electronic databases were searched: Medline, EMBASE, SPORTDiscus and CINAHL, from inception to October 2020. This review included longitudinal studies (with at least three months between at least two timepoints) published in any language, that reported any measure of function following an ACL injury that was managed either surgically or conservatively. Two independent reviewers screened titles/abstracts and the full text of potentially eligible studies. Data extraction was completed using a piloted data extraction sheet by two reviewers, with agreement determined by a third reviewer.
Results: The included studies (n=265) had a combined sample of 106,449 participants, of which 62,085 (58%) were male and 44,364 (42%) were female. Participants’ mean age was 27.5 years and a total of 17 different self-reported functional outcome measures reported. The International Knee Documentation Committee (IKDC) was the most frequently reported functional measure (n=141, 53%), followed by Lysholm (n=106, 40%), Tegner (n=80, 30%) and Knee Injury and Osteoarthritis Outcome Score (KOOS) (n=58, 22%), with the IKDC and KOOS becoming increasingly more common over the last three decades. Most of the included studies (n=196, 74%) presented a follow-up duration of at least 2 years (range 6 months to 27 years). The proportion of male to female participants increased by 10% over the last three decades- 1990s (32%) to 2010s (42%).
Conclusion: This review revealed that IKDC, Lysholm, Tegner and KOOS were the most frequent measures of function in longitudinal ACL studies. Although most studies reported a follow-up duration of longer than 2 years, almost a quarter had a follow-up duration of less than 1 year. Despite the proportion of female participants in the included studies increasing over the last 30 years, more male than female participants continue to be included in longitudinal ACL studies.
Impact/Application to the field: The results of this study can guide clinicians and researchers towards outcome measures more frequently used in longitudinal studies following ACL injury to aid in the standardisation of ACL research and further inform the effectiveness of treatment following this debilitating but common injury.
Conflict of Interest: My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.