The Clinical Efficacy and Risk Factors after Revision and Reconstruction of Anterior Cruciate Ligament.

The aim of this study was to study the clinical efficacy and prognostic factors after revision and reconstruction of anterior cruciate ligament. All the patients who underwent the first revision of anterior cruciate ligament (ACL) reconstruction in the department of sports medicine from January 2001 to December 2015 were collected. The demographic information, the first revision and reconstruction information of ACL, and the information during the first ACL reconstruction were collected. A total of 335 cases were included. Lysholm score, Tegner activity score, and IKDC subjective score at the last follow-up were significantly higher than those before operation. Compared with graft failure caused by sports injury, the postoperative scores of patients with revision due to life accidents or initial reconstruction techniques were significantly lower (P < 0.05). The postoperative Lysholm score of patients with femoral canal drilling through the tibial canal was lower than that of patients with anterior internal approach. The postoperative IKDC score of patients who underwent medial meniscus suture at the same time was higher than that of patients without meniscus combined injury. ACL revision can improve the stability and function of knee joint. Compared with the revision caused by life accident or technical reasons of primary reconstruction surgery, the patients with graft failure caused by sports injury have better postoperative recovery. Medial meniscus suture and anterior internal approach drilling of the femoral bone canal have a statistically protective effect on the clinical function after ACL revision.

EGR1 promotes the cartilage degeneration and hypertrophy by activating the Krüppel-like factor 5 and ß-catenin signaling.

Osteoarthritis is one of the most common orthopedic diseases in elderly people who have lost their mobility. In this study，we observed abnormally high EGR1 expression in the articular cartilage of patients with osteoarthritis. We also found significantly high EGR1 expression in the articular cartilage of mice with destabilized medial meniscus (DMM)-induced osteoarthritis and 20-month-old mice. In vitro experiments indicated that IL-1ß could significantly enhance EGR1 expression in primary mouse chondrocytes. EGR1 over-expression in chondrocytes using adenovirus could inhibit COl2A1 expression and enhance MMP9 and MMP13 expression. And silencing EGR1, using RNAi, had the opposite effects. Moreover, EGR1 over-expression accelerated chondrocyte hypertrophy in vitro, and EGR1 knockdown reversed this effect. We then explored the underlying mechanism. EGR1 over-expression increased Kruppel-Like Factor 5 (KLF5) protein level without influencing its synthesis. Enhanced EGR1 expression induced its integration with KLF5, leading to suppressed ubiquitination of KLF5. Moreover, EGR1 prompted ß-catenin nuclear transportation to control chondrocyte hypertrophy. Ectopic expression of EGR1 in articular cartilage aggravated the degradation of the cartilage matrix in vivo. The EGR1 inhibitor, ML264, protected chondrocytes from IL-1ß-mediated cartilage matrix degradation in vitro and DMM-induced osteoarthritis in vivo. Above all, we demonstrate the effect and mechanisms of EGR1 on osteoarthritis and provide evidence that the ML264 might be a potential drug for treating osteoarthritis in the future.