Doppler ultrasound provides clear diagnosis of tennis elbow

Neovascularity measured with power Doppler ultrasound can be used to both diagnose and rule out tennis elbow. This approach could improve patient care, as clinicians start their search sooner for less common causes of elbow pain, instead of waiting to see if treatment for tennis elbow resolves the problem.

Dr. Cornelius du Toit from Saunders Sports Medicine and colleagues from other facilities in Queensland, Australia, published their study in the British Journal of Sports Medicine, which made it available online Feb. 28.

They studied 25 patients with a mean age of 50 years. All had a diagnosis of tennis elbow in joints that had been affected for a median of 10 months, ranging from three to 120 months. Seven of these patients had two affected elbows. The other 18 had tennis elbow in only one arm, but the researchers performed ultrasound exams on both elbows.

The researchers also included 19 asymptomatic patients in the study, with a mean age of 45 years, for a total of 32 affected elbows, 18 contralateral unaffected elbows, and 38 unaffected elbows.

All patients received a gray-scale ultrasound exam, a power Doppler ultrasound exam, and the gold standard clinical exam for comparison. The researchers studied the common extensor tendon looking for neovascularity, lateral epicondyle bone spurring or irregularity, maximum anterior-posterior thickness, and echogenicity.

They found gray-scale ultrasound exams of changes in the common extensor tendon were not as accurate for diagnosis as the neovascularity shown with power Doppler ultrasound, which had a positive likelihood ratio of 45.39. The clinical severity of tennis elbow did not correlate with neovascularity scores, however, and neovascularity was spread evenly throughout the edges and deep into the tendon. Combining gray-scale and power Doppler ultrasound results provided a strong negative likelihood ratio of 0.05.

The researchers concluded that measuring neovascularity with power Doppler ultrasound is a more effective diagnostic tool for identifying tennis elbow than examining the tendon for changes visible with gray-scale ultrasound. They also recognized that combining the results of power Doppler ultrasound and gray-scale could help clinicians rule out tennis elbow when patients have similar symptoms, possibly providing appropriate treatment more quickly.