The treatment of complex radial head fractures: monopolar or bipolar prosthesis? An evidence-based decision.

Background: The goal of this study is to compare the results obtained in two cohorts of patients who were prospectively chosen and submitted to radial head arthroplasty because of complex radial head fractures, and were treated with two implants with different design. Methods: Twenty-one patients underwent unilateral radial head arthroplasty. Patients were prospectively divided in two groups: the first group received a monopolar radial head implant, and the second group received a bipolar radial head prosthesis (nine patients received a smooth-stemmed bipolar prosthesis and twelve patients received a press-fit monopolar prosthesis). Patient returned for follow-up, and a clinical and radiographic evaluation of implant function was made. Clinical outcome assessments included: arc of motion (flexion/extension, pronation/supination), MEPS (Mayo Elbow Performance Score), pain, grip strength and stability. Radiographically, periprosthetic osteolysis and arthritic changes were evaluated. Results: The Mayo scores were comparable between the two groups, as was the arc of motion. Periprosthetic osteolysis was much more common in patients who received a monopolar implant, but was not associated with a worse clinical outcome as measured via the MEPS. No correlation between patients’ age and clinical outcome was found. Conclusions: Clinical outcome at mid-term follow-up was generally good, and was similar with either implant type. Osteolysis didn’t seem to affect the clinical and functional result, but further studies are required in order to evaluate its potential impact at long-term. Other variables seemed to have an effect on the final outcome, and should thus be addressed in further studies.