Chondrocyte viability after intra-articular calcaneal fractures in humans

Background: Chondral damage from the impact of injury may contribute to the high incidence of post-traumatic arthritis after calcaneal fractures, but this has yet to be proven. We sought to study the effect of intra-articular calcaneal fractures on chondrocyte viability and to correlate these effects with injury severity, time from injury to surgery, and patient age and co-morbidities. Methods: Irreducible osteochondral fragments from 12 patients undergoing operative treatment for intra-articular calcaneal fractures were analyzed. Control cartilage was obtained from four tissue donors who died of unrelated causes. The cartilage was assessed for chondrocyte viability through the full thickness of tissue using a Live/Dead assay followed by laser scanning confocal microscopy. Patient demographics including injury classification and severity, time from injury to surgery, and patient age were recorded. Results: Chondrocyte viability from fracture patients averaged 72.8% +/- 12.9% (range 53% to 95%), which was significantly lower than the 94.8% +/- 1.5% viability observed in the control specimens (p = 0.005). Chondrocyte viability declined with higher energy injuries (p = 0.13), time from injury to surgery (p = 0.07), and increasing patient age (p = 0.07). However, none of these factors reached a level of statistical significance. Conclusions: A significant decline in chondrocyte viability occurs after intra-articular fractures of the calcaneus. This may contribute to the development of post-traumatic arthritis.