Cartilage adaptation after anterior cruciate ligament injury and reconstruction: implication of clinical management and research? A systematic review of longitudinal MRI studies.
Van Ginckel A, Verdonk P, and Witvrouw E. Osteoarthritis Cartilage. 2013; 21:1009-1024.
Take Home Message: Cartilage adaption is detectable approximately 2 years follow-up. In this time many changes which occur to the cartilage are a progression of the blunt trauma which the joint is subject to following injury.
After an athlete injures their anterior cruciate ligament (ACL), we make various treatment decisions (e.g., surgical and rehabilitation decisions) with the goal of preventing or delaying the onset of osteoarthritis (OA); however, we lack a true understanding of how cartilage adapts after an ACL injury. If we knew how cartilage changes following an ACL injury then this could help us optimize surgical methods and rehabilitation protocols to delay the development of OA. Therefore, Van Ginckel and colleagues conducted a systematic review of literature to better understand how cartilage changes over time and which factors may affect the rate of cartilage change. The authors used a standardized set of key terms to search several databases (i.e., PubMed, SportDiscus CINAL, Biomed Central, Science Direct, and Web of Science). A total of 5,338 records were identified through this search with 12 being finally selected for qualitative analysis. Two investigators determined the overall quality of the included studies; which assessed reporting, validity, and power of each study. Six of the 12 studies were high quality. Overall, the investigators determined that MRI-based macroscopic cartilage changes were undetectable until 2 years after surgery; however, microscopic changes to cartilage composition may start at the time of the injury, particularly in the lateral compartment of the knee. Researchers also concluded that baseline factors (meniscal status, bone marrow lesion, and time from injury to reconstruction) significantly increase the rate of cartilage changes.
Overall, this study helps clinicians better understand the changes that occur after injury and through the first 2 years of the recovery process. Conceivably, if clinicians are aware of the cartilage changes that occur during this time period we can better tailor rehabilitation programs to limit the furthering of these changes and/or have a preventative effect. For example, we may modify joint loading during exercises to better preserve the articular cartilage. The investigators also suggest that this better understanding may lead to clinicians making return-to-play decisions based on cartilage fragility and functional adaptations following surgery, although more long-term research is needed to better understand how these programs affect cartilage and the development of OA. Ultimately, concomitant injuries incurred at the time of ACL rupture (e.g., meniscal tear, bone marrow lesions) increase the rate of cartilage adaptation, thus speeding up the development of OA. When we see these secondary injuries it may be particularly important for us to counsel our patients about how they can reduce their risk of OA by modifying other risk factors for OA (e.g., maintaining a healthy body weight).
Questions for discussion: What guideline do you currently use when making a return-to-play decision following ACL surgery? Do you believe that incorporating other factors such as cartilage fragility could be done easily within your sports medicine team?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban
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