Optimal Radial Head Prosthesis Sizing in Elbow Trauma: A Review of Anatomical Principles and Clinical Techniques.

» This review synthesizes current evidence and techniques for optimal spherical radial head arthroplasty, focusing on the importance of accurate prosthesis sizing to ensure a successful outcome. » Replication of the native radial head's diameter and height is important. Mismatch can lead to pain, stiffness, capitellar wear, altered joint kinematics, and accelerated arthritis. » For diameter, the minimal outer diameter of the reconstructed native head is the most reliable guide. If comminution prevents this, the capitellar width on computed tomography scans provides a strong correlative measurement. » For height, the prosthesis should align with the proximal edge of the lesser sigmoid notch. Intraoperatively, direct visualization or fluoroscopic assessment of the lateral ulnohumeral joint space is recommended to detect overlengthening. » Diagnosing postoperative sizing errors is challenging. A defined radiographic technique comparing the radial head/neck length with the contralateral elbow on 45° flexion views can help quantify overlengthening.