Cartilage Injury After Acute, Isolated Anterior Cruciate Ligament Tear: Immediate and Longitudinal Effect With Clinical/MRI Follow-up.
Potter HG, Jain SK, Ma Y, Black BR, Fung S, Lyman S. Am J Sports Med. 2011 Sep 27. [Epub ahead of print]
Anterior cruciate ligament (ACL) injury is common in the athletic population and has been shown to cause an immediate reduction in function and increase the risk for long term joint degeneration. In a recent review, it was reported that 0 to 39% of patients following isolated ACL injury and 40 to 90% patients with combined ACL and meniscus injury will develop knee osteoarthritis within 10 to 15 years. Currently, there is little information regarding the health of knee joint articular cartilage and underlying bone as well as its association with location and severity of long term cartilage loss following ACL injury. The purpose of this prospective longitudinal cohort study was to quantify the articular cartilage damage and bone marrow edema (similar to a bone bruise) associated with acute ACL injury (n = 42 knees), and to measure the difference in articular cartilage loss following ACL reconstruction (n = 28 patients, typically 35 years of age) when compared to patients who opted for non-operative (conservative) treatment (n = 12 patients, typically 42 years of age). Patients with secondary ligamentous injury, intrasubstance meniscal injury, or evidence of osteoarthritis were excluded from the study to reduce the influence of those injuries on the potential risk for articular cartilage loss. Within 8 weeks of injury, all patients received a magnetic resonance imaging scan to visualize the ACL disruption and observe the presence of articular cartilage loss or bone marrow edema. At baseline, 100% of patients exhibited articular cartilage damage, particularly in the lateral compartment. At 1 year follow-up, regardless of treatment choice, there was articular cartilage loss in the lateral femoral condyle, lateral tibial plateau, medial femoral condyle, and patella. When patients followed up between 7 to 11 years after injury there was further evidence of cartilage loss in the lateral femoral condyle, medial femoral condyle, and patella. Patients who opted for non-surgical treatment were more likely to exhibit articular cartilage loss in the medial tibial plateau. Finally, the size of the bone marrow edema at baseline was associated with cartilage loss during the first three years after injury.
This is the first magnetic resonance imaging study to suggest that ACL reconstruction may protect the long-term health of knee joint articular cartilage when compared to non-operative treatment. The results of similar investigations have been highly variable due to inconsistencies in the study design, operative treatment, and population included. The current results indicate that there may be substantial cartilage loss in the lateral femoral condyle, patella, and lateral tibial plateau; however, ACL reconstruction may aid in stemming the long-term effects of ACL injury. It should be noted that the participants included were, on average, 35 years old or older which is a considerably older sample than what has been included in similar previous studies. In the case of the athletic population, it can be easy to focus on the traditional 6 month progression to return to activity when designing treatment paradigms and counseling patients regarding the injury. This study makes it clear that regardless of the treatment selected, it is essential to make patients aware of the potential for long-term joint health issues with their knee. ACL injury was accompanied by articular cartilage injury and bone marrow edema in all patients and was associated with subsequent articular cartilage loss as soon as 1 to 2 years following injury. In the case of a freshman athlete, this means that they might be well on their way to OA before graduation. Does this article change your opinion of treatment for ACL injury in the recreationally active population? Does the knowledge that 100% of patients exhibited cartilage loss immediately following ACL injury change the initial treatment of similar injuries?
Written by: Chris Kuenze
Reviewed by: Jeffrey Driban
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Potter HG, Jain SK, Ma Y, Black BR, Fung S, & Lyman S (2011). Cartilage Injury After Acute, Isolated Anterior Cruciate Ligament Tear: Immediate and Longitudinal Effect With Clinical/MRI Follow-up. The American Journal of Sports Medicine PMID: 21952715