Earlier ACL reconstruction associated with lower risk of knee osteoarthritis, finds Preclinical study

Dr. Rodeo and the HSS research team, including Theresa T. Lu, MD, PhD, St. Giles Chair for Research in the HSS Research Institute and pediatric rheumatologist, investigated the timing question in preclinical models of ACL reconstruction. In total, 16 models underwent immediate reconstruction after ACL rupture, 16 underwent surgery a week after injury, and 16 had no surgery. After four weeks, the researchers used advanced techniques to identify and measure the number of immune cells present in the spleen and iliac lymph nodes that drain from the knee.

The researchers observed an increase in several immune cell populations in the two surgical groups compared to the no-surgery group. Immune cell counts were significantly higher in the group that had delayed surgery compared to the group that underwent immediate surgery.

The investigators also assessed cartilage changes associated with osteoarthritis in the preclinical models. The group that had delayed surgery showed more severe and extensive signs of cartilage destruction than the group that had immediate surgery.

“Overall, our preclinical study suggests that immediate ACL reconstruction may lower the risk of developing knee arthritis, tying in with existing studies showing that chronic, unresolved inflammation leads to progressive arthritis after knee injury,” Dr. Rodeo says. “These results inform ongoing human studies at HSS in which we are evaluating the optimal timing of surgery and other factors that affect the role of immune cells and inflammatory responses in ligament healing. In these studies, we are evaluating changes in immune cells and inflammation in lymph nodes using magnetic resonance imaging, joint fluids and blood.”