Ultrasound with shear wave elastography in diagnosis and follow-up of common extensor tendinopathy in cases with lateral epicondylitis: a cross-sectional analytic study

Lateral epicondylitis (LE) is a common non-traumatic condition. The diagnosis of LE is typically made clinically. Some lateral epicondylitis patients can profit from supplementary imaging for a precise differential diagnosis. Recently, shear wave elastography has been increasingly attracting public attention in evaluation of tendon pathology and tissue elasticity quantitatively. The purpose of our study was to prove that shear wave elastography can be utilized in the diagnosis and follow-up of lateral epicondylitis. This cross-sectional analytic study involved 42 patients with unilateral lateral epicondylitis (30 males, 12 females with age range: 30–50 years, mean age: 39.9 ± 6 SD). The patients were reviewed by two radiologists with experience of more than 10 years, blinded to each other's results. Lateral epicnodylitis was diagnosed based on clinical criteria. The thickness of common extensor tendon and shear wave speed (SWS) were acquired in elbows bilaterally, along with values of the involved elbows in pre- and post-treatment phases. The comparison between examined groups, inter-rater and intra-rater concordance, and the diagnostic performance have been investigated with paired t-test, an intraclass correlation coefficients (ICCs), and a receiver operator characteristic curve, respectively. The patients with lateral epicondylitis showed a significantly decreased value of shear wave speed on affected side in comparison to the healthy side (P value: 0.000). The shear wave speed of diseased elbows has increased significantly following non-operative management than before therapy. The inter-rater and intra-rater concordance showed both excellent values (ICCs ranged from 0.939 to 1.000) for shear wave speed measurements. Furthermore, a 10.72 m/s cutoff limit of mean SWS (shear wave speed) for differentiating lateral epicondylitis elbows from healthy elbows showed a sensitivity and specificity of 90.5% for both. Shear wave elastography can be of value as a technique with proper reproducibility and proper diagnostic performance for evaluation and monitoring the therapeutic effect in patients with lateral epicondylitis.