Common extensor tendon thickness measurements at the radiocapitellar region in diagnosis of lateral elbow tendinopathy.

PURPOSE The aim of this study was to determine the value of measuring common extensor tendon (CET) thickness at the radiocapitellar and capitellar regions with qualitative ultrasonographic findings in the diagnosis of lateral elbow tendinopathy. MATERIALS AND METHODS The study included 164 lateral elbow tendinopathy patients (84 bilateral, 80 unilateral) matched by age, gender, and body mass index with 80 normal subjects. CET was examined using gray-scale and Doppler ultrasonography for tendinopathy, and tendon thickness was measured at two landmark locations: capitellar and radiocapitellar. RESULTS In tendinopathy, tendon thickness including the dominant capitellar region, increased in every measured location. In the capitellar region of the dominant elbow, the cut-off thickness was 5.15 mm, and in the radiocapitellar region, this value was 4.05 mm. For the non-dominant elbow, the cut-off thickness was 4.61 mm, whereas in the radiocapitellar region, this value was 3.51 mm. The greatest risk of tendinopathy was at the radiocapitellar region on the dominant side. The overall sensitivity and specificity of gray-scale findings were 54% and 88%, respectively, and the addition of Doppler readings did not alter these values. When capitellar measurements were added, the values increased to 79% and 80% for sensitivity and specificity, respectively. These values further increased to 93% and 91%, respectively, when radiocapitellar measurements were included. CONCLUSION A second tendon thickness measurement at the radiocapitellar region of CET in addition to the capitellar region is recommended on the grounds that combined qualitative and quantitative evaluation of CET increases the diagnostic per- formance of ultrasonography in lateral elbow tendinopathy.