Quantification of Reaming Debris at the Fracture Gap of Diaphyseal A2 and A3 Fractures After Reamed Intramedullary Nailing of the Sheep Tibia

Background: The aim of this study was to visualize the intramedullary bone debris after reamed nailing of long bones. To date, there is no protocol to quantify bone debris in the fracture gap. The hypothesis was to show if there are differences between A2 and A3 fractures. Methods: In this trial 17 sheep tibiae were used. On the medullary isthmus eight A2 und nine A3 fractures were produced. Afterwards, reposition, closure of the soft tissue and reaming procedure up to 10% of the bonecortex were done. For internal fixation, a plastic implant was used. The region of interest was scanned with the Micro-CT 80 and the fracture gap was contoured from a special software (SCANCO Medical AG, Switzerland). The threshold for the reaming debris was set at 549.9 mgHA/cm 3 . The analysis of the bone debris located at the fracture gap was measured by percent of debris volume to gap volume. For statistical analysis the Wilcoxon test was used and a level of significance of p < 0.05 was chosen. Results: The fracture gap width ranged from 0.3 to 1.7 mm in both groups. Comparing A2 and A3 fractures there was no significant difference concerning the percentage of reaming debris at the fracture gap. The Median of A2 fractures was 20.5 and 21% for A3 fractures. Conclusions: The results show reaming produces intramedullary bonegrafting. Despite different fracture planes of A2 and A3 fractures, no significant differences in the amount of reaming debris located at the fracture gap could be found. However the percental rate of reaming debris at the fracture gap of plain fractures is negligible. This research shows that there is potential for reaming debris to be applied effectively as a prophylactic and osteogenetic autograft. Together with the high stability of the intramedullary nail an all embracing concept of osteosynthesis could be established.