Anatomical Monopolar Press-Fit Radial Head Arthroplasty: Surgical Technique and Expected Outcomes

Abstract

In the setting of a radial head fracture, fixation is preferred whenever possible, although resection can be still considered a potential option. However, recently there has been a growing international consensus that favors the use of a radial head replacement in patients with an unfixable radial head fracture, especially if there is associated complex elbow instability. The primary technical goal of a radial head prosthesis (RHP) is to replicate the physiologic radiocapitellar tracking and the mechanical function of the native radial head. For these reasons, anatomically shaped implants have been produced to closely replicate the kinematics and the biomechanics of the native radial head in the hopes of maximizing implant longevity. Since many of the patients treated with a RHP are young and active, they have many years during which the prosthesis must articulate with the capitellar articular cartilage. An anatomically shaped RHPs can improve biomechanics and balance the elbow while approximating the native contact area and forces and should therefore theoretically reduce the capitellar wear rate and improve elbow stability. Several biomechanical studies have discussed the potential long-term value of an anatomically shaped radial head prosthesis. The few reported clinical studies confirm promising results in short- to medium-term follow-up. Osteolysis around the stem is one of the reported complications. The reported studies, however, are not conclusive enough to demonstrate superiority of an anatomic RHP over nonanatomic models. Regardless of the used model, the current knowledge supports that correct prosthesis placement, the appropriate treatment of associated injuries, and the absence of significant heterotopic ossification formation are the most important prognostic elements to achieve good outcomes after a radial head replacement.