Abstract:
"Patient-Specific Finite Element Analysis of Chronic Contact Stress Exposure After Intra-Articular Fracture of the Tibial Plafond"
This study investigates the biomechanical consequences of surgically reduced intra-articular fractures of the tibial plafond, using patient-specific finite element (FE) analysis. The research aimed to quantify how residual joint incongruities lead to altered contact stresses, which are a proposed etiology for post-traumatic osteoarthritis (PTOA). FE models were developed for 11 patients, each including a model of their fractured ankle after surgical reduction and a model of their intact, contralateral ankle. The simulation encompassed a 13-step sequence representing the stance phase of gait. A novel metric, "chronic contact stress exposure," was calculated by summing contact stresses across the gait cycle, weighted by time. This metric, considered a measure of degeneration propensity, was compared between the intact and fractured ankle pairs. The results showed that intact ankles had lower, more uniform, and centrally located peak contact stress exposures. In contrast, fractured ankles exhibited a series-average peak contact stress elevation of 38% (with a maximum of 82%) compared to their intact counterparts, a statistically significant difference (p=0.0015). Fractured ankles also had less area exposed to low stresses and a greater area with high stress. The study found that chronic contact stress over-exposures, defined as stresses exceeding a provisional 6 MPa damage threshold, ranged from nearly zero to 18 times the value seen in the matched intact ankles. This patient-specific modeling approach represents a significant step toward understanding the complex relationship between altered contact mechanics and long-term joint health following intra-articular fractures.
