Review Question - QID 213944

The patient has sustained a tibial plafond or pilon fracture as depicted in Figures A and B. IL-6 is one of many inflammatory molecules that has been found to be elevated in the synovial fluid following an intra-articular ankle fracture.

Post-traumatic arthritis following intra-articular fractures is a known complication. It commonly appears 1-2 years following injury and is related to chondrocyte death at the margins. There has not been shown to be any association between prolonged non-weight bearing, poor patient compliance with weight-bearing restrictions, and hardware reactions with the development of post-traumatic arthritis. However, literature has shown that the inflammatory molecules present in the synovial fluid can have a significant effect on the development of posttraumatic arthritis. Important inflammatory factors that have been found to be elevated include IL-6, IL-8, MMP-1, MMP-2, MMP-3, MMP-9 and MMP-10.

Adams et al. looked at the synovial fluid of 21 patients with an intra-articular ankle fracture and used the un-injured ankle as a control. They found the inflammatory molecules of GM-CSF, IL-10, IL-1 beta, IL-6, IL-8, IL-10, IL-12p70, TNF-alpha, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10 were all elevated. They concluded that these inflammatory molecules may play a role in post-traumatic arthritis development.

Adams et al. looked at the synovial fluid of 7 patients from his previous 21 patients that had intra-articular ankle fractures. They found that IL-6, IL-8, MMP-1, MMP-2, and MMP-3 were significantly elevated in comparison to the uninjured ankle. They concluded that the sustained elevated intra-articular inflammatory environment is a potential contributor to post-traumatic arthritis.

Figures A and B are sagittal and axial CT slices, respectively, that depict a tibial plafond or pilon fracture.

Incorrect Answers:
Answer 1: TGF-Beta has not been shown to be elevated in the synovial fluid and contribute to post-traumatic arthritis. However, TGF-Beta has been shown to be a factor in the inflammatory cycle, immune system signaling and bone signaling (inhibits osteoclasts via osteoprotegrin).
Answer 2: RANKL has not been shown to be elevated in the synovial fluid and contribute to post-traumatic arthritis. RANKL is an important part of bone signaling and metabolism.
Answer 3: IL-2 has not been shown to be elevated in the synovial fluid and contribute to post-traumatic arthritis. IL-2 has important functions within the immune system.
Answer 5: cAMP has not been shown to be elevated in the synovial fluid and contribute to post-traumatic arthritis. cAMP is an intra-cellular signaling molecule.