Validation of the Radiographic Union Score for HUmeral fractures (RUSHU): .

BACKGROUND

Early diagnosis and fixation of fractures unlikely to unite can prevent months of morbidity. The Radiographic Union Score for Humeral fractures (RUSHU) is a summative scoring system developed to aid identification of patients at higher risk of developing humeral shaft non-union. Plain radiographs taken six weeks after injury are given a score between four and 12 based on signs of union. Our aim was to assess the validity of the RUSHU prognostic model in an external population.

METHODS

The radiographs of fifty-seven patients were scored independently according to RUSHU methodology by three reviewers (blinded to patient outcome). Interobserver intraclass correlation (ICC) was calculated.

RESULTS

Of the cohort, six (10.5%) progressed to non-union after six months. We observed an interobserver ICC co-efficient of 0.89 (95%CI0.84,0.93) in RUSHU score at six weeks. Median score was significantly higher in the union cohort (10v5 p < 0.001). Using the score of < 8 to predict non-union gave an area under the ROC curve of 0.87 (95%CI 0.83,0.90).

CONCLUSIONS

In this retrospective single-centre study, we have demonstrated good inter-rater reliability. We would suggest that the RUSHU model be assessed in further external validation studies. RUSHU has the potential to reduce morbidity of delayed treatment of non-union.