Single‐Operator Stress Ultrasound Evaluation of Ulnohumeral Joint Instability Related to Medial Ulnar Collateral Ligament Injury

This article introduces a novel, single-operator stress ultrasound technique for evaluating medial ulnar collateral ligament (MUCL) integrity by assessing medial ulnohumeral joint (MUHJ) widening under valgus stress. Unlike prior methods requiring dual operators, specialized equipment, or the use of hand/wrist weights, this approach was designed for clinical efficiency, reproducibility, and patient comfort. By positioning the patient comfortably in a side-lying position with the elbow flexed to 50°, MUHJ width is measured at baseline (maximally apposed) and manually stressed positions, in a manner that may reduce muscular compensation, avoid viscoelastic creep, and facilitate consistency. While additional research is needed to evaluate clinical feasibility, assess reliability, and compare our technique with previously published methods of dynamic MUCL assessment, the aim of this manuscript is to describe our technique and provide a rationale for its potential utility in musculoskeletal ultrasound practice and research.