Factors which increase the risk of meniscus/cartilage lesions after ACL tear.

Are Meniscus and Cartilage Injuries Related to Time to Anterior Cruciate Ligament Reconstruction? 
Chhadia, A., Inacio, M., Maletis, G., Csintalan, R., Davis, B., Funahashi, T. American Journal of Sports Medicine, 2011, 39; 1894 – 1899.
http://www.ncbi.nlm.nih.gov/pubmed/21705649

ACL rupture results in knee instability which places articular structures, like meniscus and cartilage, at increased injury risk. It can be avoided with ACL reconstruction surgery which restores knee stability and allows subject to return to high-demand activities. Meniscus and cartilage lesions may occur at the time of ACL tear or may occur due to present instability (giving – way) episodes. This could indicate that late ACL reconstruction might be associated with increased amount of meniscal and/or cartilage lesions. However, research is somehow inconsistent. Therefore, authors decided to conduct this study with purpose of determining relationships between time to surgery, age, and gender with meniscus injury, cartilage injury, and combined meniscus and cartilage injury pattern.

The authors used the large database within the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry to evaluate time to surgery, age, and gender as risk factors for meniscus and cartilage injury and associations with meniscus repair rates in patients.

Medial meniscus injury was associated with TS (time to surgery), with the 6 to 12 months and >12 months groups both showing an increased risk of medial meniscus injury compared with the 0 to 3 months group. There was no statistically significant association between age or gender and medial meniscus injury. Lateral meniscus injury was negatively associated with female gender, showing a decreased risk of lateral meniscus injury compared with males. There were no statistically significant associations with TS or age and lateral meniscus injury. According to authors, this might suggest that lateral meniscus injuries are more likely to occur at the time of injury, and medial meniscus injuries are more likely to occur during postinjury recurrent instability episodes. Some reports suggest that the increase in meniscus injury rate with time is partially attributable to deterioration in meniscus status from the time of initial injury.

Time to surgery >12 months was associated with an increasing risk of cartilage injury compared with the 0 to 3 months group. Increasing age was associated with an increasing risk of cartilage injury. Female gender was associated with a decreasing risk of cartilage injury compared with males.

For medial meniscus repair rates, both the 3 to 6 months and >12 months groups were associated with a decreased medial meniscus repair rate compared with the0 to 3 months group. Increasing age was associated with a decreasing medial meniscus repair rate. There were no statistically significant associations between gender and medial meniscus repair. For lateral meniscus repair rates, there were no statistically significant associations with TS, gender, or age.

This study confirms notion that prolonged knee instability, due to ACL tear, increase the risk of cartilage and meniscus injury. Nevertheless, it does not suggest that each of the patients who suffered ACL tear should undergo ACL reconstruction, especially if instability episodes do not exist. Given that research shows that even if ones decide to undertake ACL reconstruction, most likely OA changes will occur, therefore decision whether to follow conservative or surgical treatment should be based on several factors and opinions.
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