Chondrocyte apoptosis following intraarticular fracture in humans.
The primary objective of the present study was to establish the degree to which chondrocyte apoptosis occurs in vivo following intraarticular fractures in humans. Fracture cartilage specimens were obtained from patients undergoing surgical intervention for fractures of the articular surface of the proximal tibia. Normal proximal tibia cartilage specimens served as controls. Apoptotic chondrocytes were identified and quantified using TUNEL analysis. The percentage of TUNEL positive chondrocytes in the fractured articular cartilage specimens (mean 18.5%, range 1-44%) was found to be an order of magnitude higher than the percentage observed in control specimens (mean 1.9%, range 0-4%). The percentage of TUNEL positive chondrocytes following intraarticular fracture is much higher than that reported for chronic degenerative conditions such as osteoarthritis and rheumatoid arthritis. These data provide strong evidence that chondrocyte apoptosis is a consequence of intraarticular fracture and suggest that chondrocyte apoptosis may play a particularly significant role in the subsequent development of post-traumatic arthritis.