Radiological Assessment of Hip Fracture Union RUSH and Modified RUSH

Abstract Objective：Intertrochanteric fracture is a common senile disease, which is mainly treated by surgery. The evaluation of postoperative healing of such fractures has always been based on qualitative evaluation of clinical and radiological indicators. Currently, there are no quantitative evaluations of hip fracture union other than the Radiographic Union Score or Hip (RUSH) score. The aim of this study was to evaluate fracture healing of intertrochanteric fractures treated with intramedullary nailing and plates using RUSH and the modified RUSH score we developed. Methods：We collected a total of 96 patients with surgically treated intertrochanteric fractures, including 46 with lateral plate fixation and 50 with intramedullary nailing. Six orthopedic surgeons assessed the overall impression of fracture union on more than 200 postoperative X-rays without knowing any information, followed by the use of RUSH and modified RUSH to evaluate the x-rays separately to see if the two methods improved the consistency of intertrochanteric fracture union. Results：the consistency of overall fracture healing impression was moderate（ICC=0.487）, RUSH and modified RUSH improved the consistency to substantial（ICC=0.80）and basically perfect（ICC=0.81）, respectively. In addition, for the evaluation of union of all intertrochanteric fractures, the overall score of plate was always higher than that of intramedullary nail. When the lateral plate and intramedullary nail were separately scored, the RUSH score of plate was basically the same as modified RUSH, while the modified RUSH of intramedullary nail was higher than modified RUSH. Ultimately,the medial (r=0.54 and R =0.53) and anterior (r=0.55 and R =0.54) and the global score (R =0.68 and R =0.68) in the single cortex showed a high correlation with the overall fracture healing impression in both RUSH and modified RUSH scores. Ultimately,medial (r=0.54 and r =0.53) and anterior (r=0.55 and r=0.54) in individual cortices and overall scores (r=0.68 and r =0.68) showed a high correlation with overall fracture healing impressions in both RUSH and modified RUSH scores. Conclusions：we developed a new hip fracture score comparable to the RUSH score that significantly improves the consistency of radiographic assessment of intertrochanteric fracture union. Most importantly, modified RUSH filled the callus formation gap in RUSH scores between cortical bridging and no cortical bridging. Therefore, we recommend the use of RUSH or a modified RUSH score to improve orthopedic surgeons' assessment of intertrochanteric fracture union.