Anterior cruciate ligament injury and radiologic progression of knee osteoarthritis: a systematic review and meta-analysis
Ajuied A, Wong F, Smith C, Norris M, Earnshaw P, Back D, And Davies A. Am J Sports Med. 2013; [Epub ahead of print].
Take Home Message: Sustaining an ACL rupture increases the likelihood of knee osteoarthritis in a 10-year follow-up period.
The current gold-standard for treating an anterior cruciate ligament (ACL) deficient knee is an ACL reconstruction, which attempts to restore basic biomechanical function and thus delaying knee osteoarthritis (OA). Unfortunately, the prevalence of knee OA after an ACL injury and the efficacy of an ACL reconstruction at preventing knee OA are still unclear. Therefore, Ajuied and colleagues completed a meta-analysis to assess the development and progression of OA at a minimum of 10 years after an ACL injury. They focused on studies that used the Kellgren & Lawrence grading system, which is a commonly used assessment of radiographic OA severity. Relevant articles were identified via the PubMed, Medline, EMBASE, and AMED databases. Two independent reviewers screened the articles for the inclusion criteria, which included surgically and non-surgically treated ACL rupture patients, patients with isolated ACL injuries or in combination with meniscal and/or medial collateral ligament injury, and radiological assessment with the Kellgren & Lawrence grade. The authors identified 9 articles for the systematic review and 6 articles for the meta-analysis. The 9 articles included 615 patients (422 male, 222 female), which included 228 (37%) patients with a known meniscal injury and 520 (85%) patients who received an ACL reconstruction (typically a bone-patellar tendon-bone autograft). At follow-up 309 (52%) out of 596 knees with a history of an ACL injury had radiographic OA (Kellgren-Lawrence Grade > 2). A knee with a prior ACL injury was almost 4 times as likely to have knee OA compared with a contralateral knee that had no ACL injury. Regardless of whether the knee had an ACL reconstruction or not they were 3 to 5 more likely to have knee OA compared with the contralateral uninjured knee.
This study provides clinicians with information supporting the concept that sustaining an ACL rupture increases the risk of OA later in life. Furthermore, performing an ACL reconstruction to restore normal knee mechanics may still leave the knee at greater risk for OA. However, clinicians must cautiously interpret these results because the meta-analysis focused on the contralateral knee as the control knee for comparison and excluded the study with radiographs of the ipsilateral joint at baseline. By excluding this study, the author eliminated the only study able to assess the true risk of disease progression. Meniscal injuries were also not accounted for, which prevents clinicians from truly understanding the long-term implications of an ACL rupture or ACL reconstruction because the meniscus has been shown to play a vital role in the long-term health of the knee joint. Regardless of these limitations this study highlights that despite an ACL reconstruction our patients may still be more likely to have knee OA later in life, which should cause all of us to pause and wonder how we can improve our current treatment strategies to protect the long-term health of the joint.
Questions for Discussion: Do you think the research needs to separate the influence of a meniscal tear with an ACL injury to make the findings more applicable to you?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban