OPTIMAL PROSTHESIS SIZING FOR RADIAL HEAD ARTHROPLASTY A Review of Current Evidence and Guidelines

Y Radial head arthroplasty is a viable surgical option when a radial head fracture cannot be reconstructed. Radial head arthroplasty provides a load-bearing articular structure against the capitellum in unstable fractured elbows. Studies have emphasized the importance of choosing the correct implant size to replicate the native radial head anatomy, citing various consequences of improperly sized radial head prostheses. Overstuffing of the radiocapitellar joint, or lengthening of the radius, has been extensively studied because of its detrimental effects on elbow biomechanics, but other types of improper sizing also have negative consequences. In the setting of severe fracture-dislocation or revision surgery, anatomic landmarks that are useful for prosthesis sizing often are missing. Various methods have been described to provide guidance for the accurate sizing of a prosthetic radial head; a retrieved radial head, the proximal edge of the lesser sigmoid notch, the radiocapitellar synovial fold, and the ulnohumeral joint space all represent useful references. Intraoperative radiographic examination is an important step while assessing implant size, including the height of the prosthetic radial head. Since no single method is perfect on its own, the surgeon should combine as many reference measures as possible, both before and during the procedure, for accurate prosthesis sizing in order to achieve successful outcomes.