O3265: A Pediatric Knee Injury Score Can Predict Need for Surgery

Background: Children and adolescents who sustain acute knee injuries (AKIs) often present to non-orthopaedists for initial assessment. Due to variation in knowledge and familiarity with AKIs, surgical diagnoses may be missed or delayed. Delays in surgery are associated with more severe pathology and poorer clinical outcomes. This study aims to facilitate early identification of surgical AKIs in young patients by developing a scoring tool that does not require sophisticated orthopaedic knowledge.

Methods: This retrospective cohort study included patients who presented ≤7 days after AKI to sports medicine clinics at a single children’s hospital between 2008 and 2024. Patients with atraumatic knee pain or physeal/extra-articular fractures were excluded. We collected data on history, physical exam, imaging, diagnosis, and treatment. The primary outcome of interest was need for surgery. Univariable analyses were followed by purposeful entry multivariate logistic regression to adjust for confounders (reported with odds ratio, OR, and 95% confidence interval, CI). The model coefficients were used to develop a scoring system.

Results: A total of 345 patients were included (mean age 13.5 ± 3.2 years, 53.0% male). After considering clinical and statistical relevance, four variables were entered into a regression model to develop a scoring tool. An effusion on exam (OR 5.1; 95% CI 2.5, 10.4; p< 0.001), age ≥14 years (OR 4.3; 95% CI 2.1, 8.5; p< 0.001), non-contact mechanism of injury (OR 3.5; 95% CI 1.8, 7.1; p< 0.001), and inability to bear weight on exam (OR 3.0; 95% CI 1.3, 6.9; p=0.01) increased the odds of undergoing surgery. These variables were adapted to a scoring system: effusion on exam, two points; age ≥14 years, two points; non-contact mechanism, one point; inability to bear weight on exam, one point. A score of ≥3 points was 87.5% sensitive and 46.3% specific for needing surgery.

Conclusion: A simple, four-variable scoring tool is preliminarily sensitive for identification of surgical knee injuries in young patients. The low specificity was expected, given the reciprocal relationship between sensitivity and specificity. Furthermore, the risks of a false positive result are far outweighed by those of a false negative (i.e., missed surgical diagnosis). This tool will be validated prospectively in the future, and may help reduce missed or delayed diagnoses if successfully implemented in non-orthopaedic settings.