Pilon Fracture With Intra-articular Injection of N-Acetylcysteine (Pilon NAC)

High energy intra-articular fractures of the distal tibia, or Pilon fracture, is a devastating injury with multiple short and long term complications. The incidence of these injuries is increasing as survival rates after motor vehicle collisions increase. The current standard of care for high energy pilon fractures is to place an external fixator at the time of injury and then provide definitive internal fixation when the soft tissue envelope allows, which is usually around 10-14 days. Arguably, the most debilitating long term complication after a high energy pilon fracture is the development of post-traumatic osteoarthritis (PTOA), which occurs in 50% or more of pilon fractures within the first 2 years of surgery. The development of osteoarthritis occurs even in the presence of adequate restoration of the tibial plafond. Part of this issue lies in the fact that ankle joint cartilage is the thinnest of any major articular joint and sustains a great deal of damage at the time of injury. This impaction and injury initiates a cascade of events that ultimately result in cartilage cell death, or chondrolysis. Chondrolysis occurs via necrosis or apoptosis. Apoptosis occurs via a caspase pathway, while necrosis of chondrocytes likely occurs secondary to overproduction of reactive oxidant species (ROS). Recent animal models have demonstrated several things: chondrocyte death is highest along fracture lines, and likely undergo necrosis as opposed to apoptosis. The reason that PTOA likely occurs in such a high percentage of pilon fractures is because of this chondrolysis, and if a method can be developed to decrease the rate of chrondrocyte necrosis, then the rate of PTOA could potentially improve and improve patient outcomes overall. A recent bovine model examined the injection of N-acetylcysteine (NAC) after an intra-articular knee fracture and its effect on the cartilage cell viability. Their study demonstrated that chondrocyte cell viability after an injection of NAC with