Purpose. Assess and report the functional and post-operative outcomes of complex acute radial head fractures with elbow instability treated by arthroplasty using an uncemented modular anatomic prosthesis. Methods. Over a 3-year period (2007–2010), 21 patients (mean age 51.9 years) were treated primarily with modular radial head arthroplasty (mean follow up of 27.1 months). Data was collected retrospectively using clinical notes, operation documentation and prospectively using validated scoring systems namely the Oxford Elbow Index, Quick DASH and the Mayo Elbow Performance Score. Associated elbow fractures, ligamentous injury and short to mid term post-operative outcomes including radiographic assessment were recorded. Results. The mean Oxford Elbow Score was 34.80 (range 20–48). The mean Quick Dash score was 26.01 (range 0–68.2). The Mayo Performance score showed 6 scored excellent, 5 scored good, 3 scored fair and 2 scored poor. Regarding post-operative outcomes, 1 patient had a radial head dislocation, 1 patient had prosthesis removal for ongoing pain and 1 patient had a total elbow replacement due to associated proximal ulna fracture non-union. 11 patients had an associated ligamentous injury of which 6 had an associated coronoid fracture. Of note, 7 patient's radiographs showed early signs of implant loosening; this was mainly asymptomatic. Conclusions. With regard to complex radial head fractures with elbow instability, patient outcome measures showed good functionality and overall patient satisfaction despite radiographic evidence of loosening. Post-operative complication rates were low. These findings support the use of this radial head prosthesis in arthoplasty surgery for the treatment of complex acute radial head fractures with elbow instability

Background. Radial head arthroplasty (RHA) is a popular method of treatment for complex fractures of the radial head. The purpose of this study was to investigate patient outcomes and radiographic findings associated with a single anatomical monopolar press-fit radial head system commonly used for the treatment of radial head fractures. Methods. A retrospective review of prospectively collected data was performed for a consecutive series of patients treated with RHA between November 2007 and April 2014. Patients with a minimum of 12-month follow-up were included. Most recent radiographs were evaluated for loosening, stress shielding, and instability. Post-operative motion and outcomes were reported at most-recent follow-up. Results. At an average follow-up of 30 months, 7 of the 17 patients (41%) demonstrated radiographic loosening. Six of the 10 patients (60%) without loosening demonstrated stress shielding (average 6mm). Functional outcome scores included a mean ASES of 74, MEPS of 87, VAS Pain of 1, VAS Function of 8 and SANE of 79. Average flexion-extension arc was 13°–138°, and average pronation-supination was 77°–76° (Figure 1). Of the patients with radiographic loosening, 86% had undergone RHA with an associated ligamentous injury of the elbow. Satisfaction among patients was high, as no patient reported an unsatisfactory outcome. Conclusions. The use of an anatomic, press-fit monopolar RHA in the management of acute complex radial head fractures has yielded excellent clinical outcomes despite high rates of radiographic loosening and stress shielding. Press-fit RHA in the setting of ligamentous injury warrants further investigation due to a high rate of implant loosening observed