Heel fractures cause chondrocyte viability decline
By Elaine Fiedler
Researchers investigating chondrocyte viability after intra-articular calcaneal fractures found a significant decline, which may contribute to the high incidence of posttraumatic arthritis. The authors of Paper 219 also reported that the extent of decline appears to vary with patient age and injury factors such as severity and time from injury to surgery.
In this IRB-approved study, investigators compared irreducible chondral fragments from 11 patients undergoing operative treatment for intra-articular calcaneal fractures (12 fractures) to control cartilage 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. Data was analyzed statistically using ANOVA, and correlations by linear regressions.
The authors also recorded patient demographics including patient age, time from injury to surgery and injury classification and severity.
The average age of the fracture patients was 33 years (range: 19 to 61 years); the average age of the donors was 47 years (range: 46 to 48 years). The average time between injury and surgery was 21 days (range: 14 to 42 days). Seven patients had Sanders Type II fractures; three had Type III fractures, and two had Type IV fractures. A similar degree of severity was noted in soft tissue injury (seven as Tscherne grade 1, two as grade 2 and three as grade 3).
Chondrocyte viability from the fracture patients averaged 72.8 percent (±12.9 percent), which was significantly lower than the 94.8 percent (±1.5 percent) 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).
A significant decline in chondrocyte viability occurs after intra-articular fractures of the calcaneus, which probably plays a role in the high risk of posttraumatic arthritis after calcaneus fractures. The authors note, however, “there is a moderate degree of variability from patient to patient with some patients demonstrating very little cellular necrosis. This variability at the cellular level may explain why two patients who have both been anatomically reduced may experience very different clinical and radiographic outcomes.”
Investigators also found a strong trend toward significance when correlating chondrocyte viability with patient age. Older patients generally had lower chondrocyte viability after fracture. Chondrocyte necrosis also increased with longer times between injury and surgery.
The authors included Scott T. Ball, MD; Kyle Jadin, PhD; R. Todd Allen, MD, PhD; Alexandra K. Schwartz, MD; Robert L. Sah, MD, ScD, and Michael E. Brage, MD—all of San Diego, Cal.