Background: Ultrasonography (US) is often used in the assessment of lateral epicondylitis (LE). The strength of evidence supporting its role is, however, not well-documented.
Purpose: To describe and compare the US tendinopathic changes observed in patients with LE and the general population, including any correlation between patient characteristics and US outcomes.
Study design: Cross-sectional study; Level of evidence, 3.
Methods: Tendon thickness, color Doppler activity, and bone spur were assessed by US in 264 participants with healthy elbows and 60 patients with chronic LE. In addition to patient characteristics, Patient-Rated Tennis Elbow Evaluation (PRTEE) score, pain, and disability were recorded.
Results: Depending on the measurement technique used, mean LE tendon thickness increased by 0.53 mm (10.2%) or 0.70 mm (14.5%) as compared with the contralateral arm and 0.40 mm (7.9%) or 0.41 mm (8.5%) as compared with the general population. Mean color Doppler activity (scale, 0-4) was 3.47 in the LE arm versus 0.13 in the contralateral asymptomatic arm and 0.26 in the general population. Bone spur was observed in 78% of the LE arms as opposed to 45% in the contralateral arms and 50% in the general population. In the LE group and the general population, the prevalence of bone spur increases with age. No correlations were observed with pain, disability, PRTEE, and disease duration.
Conclusion: Increased common extensor tendon thickness is part of the tendinopathic changes observed in LE. However, given the marked variation in natural tendon thickness and small increases in tendon thickness in patients with LE, this technique cannot be used as a stand-alone diagnostic tool but rather as a supplement to the overall assessment. The contralateral elbow (if asymptomatic) is a better tendon thickness comparator than a general population mean value. Color Doppler activity is an indicator of ongoing tendinopathy and supports the LE diagnosis, but it is not pathognomonic for the condition. Absence of Doppler activity in a patient with suspected LE should raise suspicion of other diagnoses. Identification of a bone spur is of very limited clinical value given the high prevalence in the general population. The important outcomes of pain, disability, PRTEE, and disease duration did not correlate with any of the investigated US techniques.
Keywords: bone spur; color Doppler; lateral epicondylitis; tendon thickness; tennis elbow.