Ultra sonographic findings for chronic lateral epicondylitis.

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% to 100%, a 90% specificity with a 98% PPV and a high likelihood ratio (9 to 10). 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.