Anterior cruciate ligament (ACL) injury initiates a biochemical cascade that leads to cartilage degradation and the development of posttraumatic osteoarthritis (PTOA). ACL and acute traumatic meniscus tears have been linked to the development and progression of PTOA. As such, there is an unmet need to identify treatments that may alter the progression of PTOA following ACL meniscus injury. The overarching hypothesis of this project is that intraarticular administration of long-acting anti-inflammatory agents will alter the progression of PTOA following ACL reconstruction.
The current standard of care for patients with combined ACL and meniscus injuries consists of surgical treatment often with a short course of postoperative physical therapy. However, the current mechanically-based standard of care does not address the persistent inflammatory process that promotes cartilage degradation and PTOA progression. The pro-inflammatory stimulation of meniscus cells increases matrix metalloproteinase (MMP) and cytokine activity, and the combination of pro-inflammatory cytokines and compressive loading like what may be seen during sporting and high demand activities further results in degradative enzyme activity and increased production of pro-inflammatory mediators. In this way, the meniscus plays an active role in promoting the cycle of articular cartilage degradation and PTOA progression after ACL reconstruction.
Reducing MMP and cytokine activity after ACL and meniscus injury may alter the progression of PTOA for this at-risk patient population. After ACL injury and reconstruction demonstrate triamcinolone acetonide effectively reduces cartilage degradation, the inflammatory cascade and corresponding cartilage degradation are reinitiated after surgery, hyaluronate treatment 1 week after surgery unsuccessfully mitigates the inflammatory and catabolic processes, and pain and persistent postsurgical cytokine activity at 4 weeks were predictive of inferior knee biomechanics 6 months after surgery. In addition, long-acting agents may provide a greater treatment effect as temporal regulation of cytokine activity may more successfully alter the pro-inflammatory environment than shorter-duration treatments. These results identify that long-acting anti-inflammatory treatment is needed to alter the path of PTOA following meniscus injury and administration 8 weeks after surgery may offer the optimal timing of treatment.
The model whereby femoral shape change and cytokine activity are mediated by a long-acting anti-inflammatory agent (extended-release triamcinolone acetonide) will be tested. Femoral shape changes have been demonstrated after ACL injury and reconstruction, with shape changes in the first 6 months after surgery correlating with subsequent MRI evidence of cartilage degradation and inferior patient-reported outcomes 3 years postoperatively. A Phase 2a, double-blind, placebo-controlled, randomized controlled trial will be performed. The trial will determine if a long-acting anti-inflammatory agent (extended-release triamcinolone acetonide) improves patient-reported outcomes and/or lessens progressive bone shape changes or cartilage breakdown when compared to placebo (saline). Saline was chosen as the placebo as saline has few potential risks and rare adverse events and is the most commonly used placebo treatment option used in knee osteoarthritis research.
