Articular fragment restoration is critical to mitigate post-traumatic osteoarthritis in a porcine pilon fracture model

OBJECTIVE: During articular fracture reconstruction, orthopedic surgeons are frequently faced with the dilemma of retaining small articular fragments versus discarding these fragments. The purpose of this study was to compare post-traumatic osteoarthritis (PTOA) development between tibial plafond fractures and plafond fractures with a missing articular fragment (MF) in a porcine model. DESIGN: High-energy tibial plafond fractures in skeletally mature Yucatan mini pigs (n ​= ​12) were created. During surgery, a 3 ​× ​3 mm section of the articular surface was removed in six animals (MF group). Ankle synovial fluid was analyzed for IL-1β, IL-1Ra, IL-6, IL-8, and IL-10 concentrations obtained at initial surgery and 12 weeks post-surgery. Plafond and talus sections were evaluated for subchondral bone porosity and stained with Sanderson's Rapid Bone Stain and blindly evaluated to determine the Osteoarthritis Research Society International (OARSI) grade and vascular invasion. RESULTS: Fractured ankles had greater concentrations of IL-1β, IL-1Ra, IL-6, IL-8, and IL-10 compared to control ankles. There was no difference in cytokine concentrations between fractured and fractured ​+ ​MF ankles. Fractured ankles had significantly greater bone porosity, vascular invasion, and OARSI grade as compared to the control group. In comparing tibial plafonds, the MF group had significantly more bone porosity, more vascular invasion, and a higher average OARSI grade than the anatomically reconstructed group. In comparing the talus, the MF group had higher average OARSI grade and similar bone porosity. CONCLUSIONS: Articular fractures with a MF had worse PTOA development as measured by bone porosity, vascular invasion, and OARSI grade than the anatomically reconstructed fractures.