Comparison Of Ultrasonography To Mri In The Diagnosis Of Lower Extremity Bone Stress Injuries.

Abstract

BACKGROUND: Bone-stress injuries (BSIs) are relatively common in college-level athletes and can result in substantial disability leading to prolonged leave from sport when diagnosed in more advanced stages. Early detection and intervention of BSIs in this population is critical given the demanding NCAA schedules and expectations for timely returns to full activity. Currently, the gold standard for detecting early-stage BSIs is magnetic resonance imaging (MRI), however with recent global advancements in ultrasound technology, there are new opportunities for early diagnosis of BSIs in the sports medicine clinic and training-room settings. PURPOSE: To examine the sensitivity and specificity of ultrasound imaging (USI) in the diagnosis of BSIs, utilizing MRI as the gold standard. STUDY DESIGN: Cohort Study (diagnosis) METHODS: Thirty-nine elite primarily NCAA division 1 athletes (mean age, 21.64 years; standard deviation [SD], 7.24; range 18-62) underwent USI and MRI for clinical suspicion of a BSI in the lower extremity. 32 females and 7 males enrolled, with running as the most common sport (44%). An 8-point assessment system was utilized on USI for detecting BSI, and the Fredericson Criteria was used to classify MRI findings. Sensitivity, specificity, positive and negative predictive values (PPV and NPV) of USI compared to MRI were calculated. RESULTS: Using MRI, there were 31 (79%) athletes with a positive and 8 participants with a negative BSI diagnosis. The most common bone injuries were metatarsal (51%) and tibia (33%). Aaverage days to onset was 31.87 (SD = 34.20). Compared to MRI, USI demonstrated 0.77 sensitivity (95% confidence interval [CI], 0.59-.0.90) and 0.75 specificity (95% CI, 0.35-0.97) in detecting BSI, with a PPV of 0.92 (95% CI, 0.75-0.99) and NPV of 0.46 (95% CI, 0.19-0.75). Subcutaneous edema was the most sensitive (0.81, 95% CI=0.63-0.93) USI finding but the least specific (0.25, 95% CI=0.03-0.65), while calcified bone callus was the most specific (0.88, 95% CI=0.47-1.00) but least sensitive (0.26, 95% CI=0.12-0.45). CONCLUSION: USI is a reliable screening tool for sports medicine providers to combine with their clinical evaluation in the diagnosis of bone stress injuries. Further research is ongoing to determine the role of USI in follow-up care and return-to-play protocols.