Radial Collateral Ligament of the Elbow

OBJECTIVES: An abnormality of the radial collateral ligament (RCL) in the setting of lateral epicondylitis can indicate a poor clinical outcome; therefore, accurate assessment is important. The purpose of this study was to characterize the proximal RCL attachment, or footprint, as seen on sonography using cadaveric dissection correlation and magnetic resonance arthrography. METHODS: For the first part of this study, 4 cadaveric elbow specimens were imaged with sonography before and after dissection to characterize the RCL. After Institutional Review Board approval with consent waived, 26 consecutive magnetic resonance (MR) arthrograms of the elbow were identified. The sonograms and MR arthrograms were retrospectively reviewed to measure the length of the RCL footprint and its percentage of the combined RCL and common extensor tendon (CET) humeral footprints. RESULTS: The mean RCL footprint length and percentage of the combined RCL and CET footprints were 8.4 mm (range, 7.4-10.0 mm) and 54% as measured from the elbow specimen sonograms and 9.1 mm (range, 6.4-12.5 mm) and 54% as measured from the MR arthrograms. The mean RCL footprint length combining data from specimens and MR arthrograms was 8.9 mm (range, 6.4-12.5 mm), covering 54% of the combined RCL and CET footprints. CONCLUSIONS: The RCL can be differentiated from the CET on sonography with knowledge of the RCL humeral footprint extent, which measured 8.9 mm in length and comprised 54% of the combined RCL and CET footprints.