Degenerative changes in the knee 2 years after anterior cruciate ligament rupture and related risk factors: a prospective observational follow-up study.
Van Meer BL, Oei EHG, Meuffels DE, van Arkel ERA, Verhaar JAN, Bierma-Zeinstra SMA, and Reijman M. Am J Sports Med. 2016. [Epub Ahead of Print].
Take Home Message: Among 143 people with an anterior cruciate ligament (ACL) rupture, 40% had worsening osteophytes or cartilage defects during the first 2 years after injury. Males and people with a meniscal tear, medial cartilage defect at baseline, or medial bone marrow lesion at 1-year follow-up may be at risk for these early structural changes.
Sports Med Res has summarized several studies reporting that an athlete is at increased risk for knee osteoarthritis after an anterior cruciate ligament (ACL) injury. Unfortunately, we still need a deeper understanding of the early structural changes to design effective screening tools and interventions. Therefore, van Meer and colleagues completed a prospective cohort study to identify which factors are related with early (2 years post-surgery) structural changes as assessed by magnetic resonance imaging (MRI). A total of 143 patients (18-45 years of age, 49 females) with a diagnosed ACL rupture completed the study. At baseline (within 6 months of injury), 1 year, and 2 years post injury participants completed questionnaires and received a physical examination. Participants completed questionnaires to assess patient characteristics, activity level, and frequency of giving away. Participants underwent MRI at baseline, 1 year, and 2 years post injury to assess cartilage defects, joint effusion, presence of bone marrow lesions, and meniscal tears, progression of cartilage defects, and progression of osteophytes. During the 2-year follow-up period, 40% of participants had progression of cartilage defects and/or osteophytes. The authors noted that physical activity level, episodes of giving way during the first year, and treatment strategy (surgery, delayed surgery, conservative care) were unrelated to structural changes. The authors found 4 determinants of worsening cartilage defects:
1. male sex (4.4 times more likely to have worsening)
2. medial cartilage defects at baseline (3.7 times more likely to have worsening)
3. presence of a medial bone marrow lesion at 1-year follow-up (5.2 times more likely to have worsening)
4. presence of a meniscal tears (6.4 times more likely to have worsening)
Overall, this study provides clinicians with further insight into the connection between ACL rupture and early structural changes that may precede osteoarthritis. However, it is important to recognize that we are unsure about how many people who had worsening cartilage defects will develop symptomatic knee osteoarthritis. Regardless, clinicians should be aware of these risk factors because they may help us screen patients who are high risk and may need to be educated about their risk and advised to seek early care or increased screening. Furthermore, these predictive factors may also be used for targeting future pharmacological and rehabilitative treatment options. Future research may also clarify if baseline and 1 year follow-up MRIs may be valuable. For example, post-traumatic bone marrow lesions usually resolve within the first 12 months. However, patients who have a medial bone marrow lesion at 12 months may be more likely to have cartilage loss during the first 2 years after injury. Until more research can be completed, clinicians should recognize that male patients or patients with meniscal tears or cartilage defects at baseline might be at greater risk for cartilage loss over the next 2 years. Clinicians should educate these patients about their risk and steps they can take to reduce the risk for joint symptoms and osteoarthritis (e.g., weight management, adopting strategies to prevent future injuries).
Questions for Discussion: Do you discuss the long-term implications of injury with your patients? If so, are your patients are receptive to this counseling?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban
van Meer, B., Oei, E., Meuffels, D., van Arkel, E., Verhaar, J., Bierma-Zeinstra, S., & Reijman, M. (2016). Degenerative Changes in the Knee 2 Years After Anterior Cruciate Ligament Rupture and Related Risk Factors: A Prospective Observational Follow-up Study The American Journal of Sports Medicine, 44 (6), 1524-1533 DOI: 10.1177/0363546516631936