Purpose: To assess which individual gray-scale and color Doppler US findings and their combination are strongly associated with lateral epicondylitis. Also to determine whether chronic lateral epicondylitis is possible without any positive US findings.
Methods: 49 patients (6 bilateral) underwent gray-scale ultrasonic imaging between 2005 to 2007. All had a history of lateral epicondylitis and had concordant pain during US probe compression in the common extensor region. Mean patient age was 47 (sd 7.7) years; M/F ratio 21/28; L/R ratio 17/32. Five symptom free volunteers (all bilateral) with a mean age of 36 (sd 8.7) years; M/F = 4/6; L/R = 5/5.
Results: Neovascularity determined by color Doppler and four gray-scale US findings – a convex external contour, an erosive lateral epicondular cortex, internal calcifications, or a tear – have a specificity and PPV of 100% with conclusive likelihood ratios. However, only the sensitivity for neovascularity is above 50%. A combination of gray-scale and color Doppler shows a sensitivity between 92% to100%, a 90% specificity with a 98% PPV and a high likelihood ratio (9 to10).
Conclusion: The combination of gray-scale and color Doppler changes is diagnostically superior to identify chronic lateral epicondylitis. Signs which confirm the diagnosis are a convex boundary, an erosive cortex, internal calcifications, a tear, and neovascularity. Patients with positive clinical signs and concordant pain but no US findings require further MRI evaluation.