Predicting the Behaviour of Humeral Shaft Fractures: An Independent Validation Study of the Radiographic Union Score for HUmeral Fractures (RUSHU) and Value of Assessing Fracture Mobility
Objectives: To externally validate the Radiographic Union Score for Humeral fractures (RUSHU) and to quantify the predictive relationship of fracture motion on physical examination to non-union. Design: Retrospective cohort study. Setting: Single institutional centre (University teaching hospital). Patients: 92 consecutive patients undergoing non-operative treatment of a diaphyseal humeral shaft fracture were identified over a 4-year period. The average age of the population was 62 years and 42% of the cohort was male. Intervention: Clinical examination for fracture stability was routinely performed on patients by the treating physicians. Radiographic assessment of fracture callus (RUSHU score) at 6-weeks was retrospectively determined. Patients were followed up until union. Main outcome measurements: Stability was graded as motion at the fracture site or the humerus moving as a single functional unit. Results: Fractures with RUSHU score ≤7 were 14 times more likely to proceed to non-union at 6-months (78% sensitivity, 80% specificity). The time to union was 49 weeks for a RUSHU score of ≤7 versus 16 weeks for a RUSHU score of ≥8. The number of operations needed to avoid one non-union was 1.7. Fractures mobile at 6-weeks were 6.5 times more likely to proceed to non-union at 6-months (77% specificity, 67% sensitivity). Mobile fractures had a longer time to union (41 weeks) than non-mobile fractures (17 weeks). Conclusion: The RUSHU score and clinical assessment of fracture mobility are effective and valid tools in identifying patients at risk of developing non-union of humeral shaft fractures and can enhance early decision making in fracture management.
- Trauma and Orthopaedics