Posterior translation of the radial head in magnetic resonance imaging of lateral epicondylitis: a cross-sectional study

Abstract Background:Disruption of the lateral collateral ligament complex (LCLC) causes posterolateral rotatory instability (PLRI). This is usually post-trauma but may also result from lateral epicondylitis. The present study examined the amount of posterior translation of the radial head related to LCLC injury, Common extensor tendon (CET) injury, and Baker classification in patients with lateral epicondylitis.Methods:We retrospectively evaluated the findings for patients with lateral epicondylitis of the humerus who underwent surgery at our institution between April 2016 and July 2021. Fifteen elbows with preoperative coronal and sagittal MR images were included. We evaluated posterior translation of the radial head on sagittal elbow MRI and compared it according to LCLC and CET lesion classifications in lateral epicondylitis.Results:Mean patient age was 49 years. All patients received single or multiple steroid injections before surgery. In the LCLC classification, four, nine, and two lesions were classified as LCLC0, LCLC1, and LCLC2, respectively. The mean radio-humeral distance (RHD) values for the LCLC lesions were 0.65 mm in LCLC0, 2.46 mm in LCLC1, 2.22 mm in LCLC2. RHD was significantly greater in LCLC1 than in LCLC0. In the CET classification, five, six, and four lesions were classified as CET1, CET2, and CET3, respectively. The mean RHD values for the CET lesions were 1.33 mm in CET1, 2.68 mm in CET2, 1.48 mm in CET3.Conclusions:Posterior translation of the radial head on MRI in patients with lateral epicondylitis is greater in cases with LCLC lesions than in those with normal findings.