OTA 2005 Posters
Scientific Poster #71 Basic Science
Cell Viability of Human Chondrocytes after Traumatic Joint Disruption
Purpose: Posttraumatic arthritis (PTA) is a common and well recognized problem that affects patients of all ages. Various etiologies have been proposed for PTA, one of which entails altered cell viability of chondrocytes after cartilage disruption with articular fracture. To date, few studies have looked at what happens to human chondrocytes after joint trauma. The purpose of this study is to characterize the viability of human chondrocytes after fracture, as well as to determine if viability is affected by location of the chondrocyte relative to fracture.
Methods: Osteochondral fragments (n=36) were obtained and analyzed within 24 hours. All fragments were not usable in joint reconstruction and would otherwise have been discarded. The joint from which the fragment was obtained, age, sex, and number of days since trauma were recorded. The time from injury averaged 4.6 days. Using a straight-edged razor, each fragment was halved in a plane orthogonal to the articular surface and then labeled with a live/dead assay (Molecular Probes). Confocal microscopy was used to view the cartilage both at and away from the fractured edge. The percentage of viable cells was determined for discrete zones of articular cartilage (superficial, middle, deep, and osteochondral) using an image analysis package (NIH Scion Image).
Results: Cell viability was quantified in 29 samples. The mean fraction of live cells for the nonfractured region was 42.1%, 84.2%*, 74.5%*, and 60.0% for the superficial, middle, deep, and osteochondral zones, respectively (*P<0.05 versus superficial). The mean fraction of live cells for these zones located along the fractured edge was 24.1%, 37.6%*, 43.6%*, and 36.5% (*P<0.05 versus superficial). The mean fraction of live cells in each nonfractured zone was significantly greater (P<0.05) than its counterpart along the fractured edge. Control specimens (nonfractured) showed 97.5% viability.
Conclusion/Significance: These data suggest that the greatest decrease in chondrocyte viability after articular fracture occurs along the fractured edge. The middle and deep zones of the cartilage are privileged areas with high chondrocyte viability relative to other zones. These findings might provide further insight into the role of chondrocyte death in PTA.